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serotonin illustration“A theory that is wrong is considered preferable to admitting our ignorance.” – Elliot Vallenstein, Ph.D.

The idea that depression and other mental health conditions are caused by an imbalance of chemicals in the brain is so deeply ingrained in our psyche that it seems almost sacrilegious to question it.

Direct-to-consumer-advertising (DCTA) campaigns, which have expanded the size of the antidepressant market (Donohue et al., 2004), revolve around the claim that SSRIs (the most popular class of antidepressants) alleviate depression by correcting a deficiency of serotonin in the brain.

For example, Pfizer’s television advertisement for Zoloft states that “depression is a serious medical condition that may be due to a chemical imbalance”, and that “Zoloft works to correct this imbalance.”

Other SSRI advertising campaigns make similar claims. The Effexor website even has a slick video explaining that “research suggests an important link between depression and an imbalance in some of the brain’s chemical messengers. Two neurotransmitters believed to be involved in depression are serotonin and norepinephrine.” The video goes on to explain that Effexor works by increasing serotonin levels in the synapse, which is “believed to relieve symptoms of depression over time.”

These days serotonin is widely promoted as the way to achieve just about every personality trait that is desirable, including self-confidence, creativity, emotional resilience, success, achievement, sociability and high energy. And the converse is also true. Low serotonin levels have been implicated in almost every undesirable mental state and behavioral pattern, such as depression, aggressiveness, suicide, stress, lack of self-confidence, failure, low impulse control, binge eating and other forms of substance abuse.

In fact, the idea that low levels of serotonin cause depression has become so widespread that it’s not uncommon to hear people speak of the need to “boost their serotonin levels” through exercise, herbal supplements or even sexual activity. The “chemical imbalance” theory is so well established that it is now part of the popular lexicon.

It is, after all, a neat theory. It takes a complex and heterogeneous condition (depression) and boils it down to a simple imbalance of two to three neurotransmitters (out of more than 100 that have been identified), which, as it happens, can be “corrected” by long-term drug treatment. This clear and easy-to-follow theory is the driving force behind the $12 billion worth of antidepressant drugs sold each year.

However, there is one (rather large) problem with this theory: there is absolutely no evidence to support it. Recent reviews of the research have demonstrated no link between depression, or any other mental disorder, and an imbalance of chemicals in the brain (Lacasse & Leo, 2005; (Valenstein, 1998).

The ineffectiveness of antidepressant drugs when compared to placebo cast even more doubt on the “chemical imbalance” theory. (See my recent articles Placebos as effective as antidepressants and A closer look at the evidence for more on this.)

Folks, at this point you might want to grab a cup of tea. It’s going to take a while to explain the history of this theory, why it is flawed, and how continues to persist in light of the complete lack of evidence to support it. I will try to be as concise as possible, but there’s a lot of material to cover and a lot of propaganda I need to disabuse you of.

Ready? Let’s start with a bit of history.

The history of the “chemical imbalance” theory

The first antidepressant, iproniazid, was discovered by accident in 1952 after it was observed that some tubercular patients became euphoric when treated with this drug. A bacteriologist named Albert Zeller found that iproniazid was effective in inhibiting the enzyme monoamine oxydase. As its name implies, monoamine oxydase plays an essential role in inactivating monoamines such as epinephrine and norepinephrine. Thus, iproniazid raised levels of epinephrine and norepinephrine which in turn led to stimulation of the sympathetic nervous system – an effect thought to be responsible for the antidepressant action of the drug.

At around the same time, an extract from the plant Rauwolfia serpentina was introduced into western psychiatry. This extract had been used medicinally in India for more than a thousand years and was thought to have a calming effect useful to quite babies, treat insomnia, high blood pressure, insanity and much more. In 1953 chemists at Ciba, a pharmaceutical company, isolated the active compound from this herb and called it reserpine.

In 1955 researchers at the National Institutes of Health reported that reserpine reduces the levels of serotonin in the brains of animals. It was later established that all three of the major biogenic amines in the brain, norepinephrine, serotonin, and dopamine, were all decreased by reserpine (again, in animals).

In animal studies conducted at around the same time, it was found that animals administered reserpine showed a short period of increased excitement and motor activity, followed by a prolonged period of inactivity. The animals often had a hunched posture and an immobility that was thought to resemble catatonia (Valenstein, 1998). Since reserpine lowered levels of serotonin, norepinephrine and dopamine, and caused the effects observed in animals, it was concluded that depression was a result of low levels of biogenic amines. Hence, the “chemical imbalance” theory is born.

However, it was later found that reserpine only rarely produces a true clinical depression. Despite high doses and many months of treatment with reserpine, only 6 percent of the patients developed symptoms even suggestive of depression. In addition, an examination of these 6 percent of patients revealed that all of them had a previous history of depression. (Mendels & Frazer, 1974) There were even reports from a few studies that reserpine could have an antidepressant effect (in spite of reducing levels of serotonin, norepinephrine and dopanmine).

As it turns out, that is only the tip of the iceberg when it comes to revealing the inadequacies of the “chemical imbalance” theory.

The fatal flaws of “chemical imbalance” theory

As Elliot Valenstein Ph.D., Professor Emeritus of psychology and neuroscience at Michigan University, points out in his seminal book Blaming the Brain, “Contrary to what is often claimed, no biochemical, anatomical or functional signs have been found that reliably distinguish the brains of mental patients.” (p. 125)

In his book, Valenstein clearly and systematically dismantles the chemical imbalance theory:

  1. Reducing levels of norepinephrine, serotonin and dopamine does not actually produce depression in humans, even though it appeared to do so in animals.
  2. The theory cannot explain why there are drugs that alleviate depression despite the fact that they have little or no effect on either serotonin or norepinephrine.
  3. Drugs that raise serotonin and norepinephrine levels, such as amphetamine and cocaine, do not alleviate depression.
  4. No one has explained why it takes a relatively long time before antidepressant drugs produce any elevation of mood. Antidepressants produce their maximum elevation of serotonin and norepinephrine in only a day or two, but it often takes several weeks before any improvement in mood occurs.
  5. Although some depressed patients have low levels of serotonin and norepinephrine, the majority do not. Estimates vary, but a reasonable average from several studies indicates that only about 25 percent of depressed patients actually have low levels of these metabolites.
  6. Some depressed patients actually have abnormally high levels of serotonin and norepinephrine, and some patients with no history of depression at all have low levels of these amines.
  7. Although there have been claims that depression may be caused by excessive levels of monoamine oxydase (the enzyme that breaks down serotonin and norepinephrine), this is only true in some depressed patients and not in others.
  8. Antidepressants produce a number of different effects other than increasing norepinephrine and serotonin activity that have not been accounted for when considering their activity on depression.

Another problem is that it is not now possible to measure serotonin and norepinephrine in the brains of patients. Estimates of brain neurotransmitters can only be inferred by measuring the biogenic amine breakdown products (metabolites) in the urine and cerebrospinal fluid. The assumption underlying this measurement is that the level of biogenic amine metabolites in the urine and cerebrospinal fluid reflects the amount of neurotransmitters in the brain. However, less than one-half of the serotonin and norepinephrine metabolites in the urine or cerebrospinal fluid come from the brain. The other half come from various organs in the body. Thus, there are serious problems with what is actually being measured.

Finally, there is not a single peer-reviewed article that can be accurately cited to support claims of serotonin deficiency in any mental disorder, while there are many articles that present counterevidence. Furthermore, the Diagnostic and Statistical Manual of Mental Disorders (DSM) does not list serotonin as the cause of any mental disorder. The American Psychiatric Press Textbook of Clinical Psychiatry addresses serotonin deficiency as an unconfirmed hypothesis, stating “Additional experience has not confirmed the monoamine depletion hypothesis” (Lacasse & Leo, 2005).

When all of this evidence is taken in full, it should be abundantly clear that depression is not caused by a chemical imbalance.

But, as Valenstein shrewdly observes, “there are few rewards waiting for the person who claims that “the emperor is really nude” or who claims that we really do not know what causes depression or why an antidepressant sometimes helps to relieve this condition.”

How have we been fooled?

There are several reasons the idea that mental disorders are caused by a chemical imbalance has become so widespread (and none of them have anything to do with the actual scientific evidence, as we have seen).

It is known that people suffering from mental disorders and especially their families prefer a diagnosis of “physical disease” because it does not convey the stigma and blame commonly associated with “psychological problems”. A “physical disease” may suggest a more optimistic prognosis, and mental patients are often more amenable to drug treatment when they are told they have a physical disease.

Patients are highly susceptible to Direct-to-Consumer-Advertising (DCTA). It has been reported that patients are now presenting to their doctors with a self-described “chemical imbalance” (Kramer, 2002). This is important because studies show that patients who are convinced they are suffering from a neurotransmitter defect are likely to request a prescription for antidepressants, and may be skeptical of physicians who suggest other interventions such as cognitive behavioral therapy (DeRubeis et al., 2005). It has also been shown that anxious and depressed patients “are probably more susceptible to the controlling influence of advertisements (Hollon MF, 2004).

The benefit of the chemical imbalance theory for insurance companies and the pharmaceutical industry is primarily economic. Medical insurers are primarily concerned with cost, and they want to discourage treatments (such as psychotherapy) that may involve many contact hours and considerable expense. Their control over payment schedules enables insurance companies to shift treatment toward drugs and away from psychotherapy.

The motivation of the pharmaceutical companies should be fairly obvious. As mentioned previously, the market for antidepressant drugs is now $12 billion. All publicly traded for-profit companies are required by law to increase the value of their investor’s stock. Perhaps it goes without saying, but it is a simple fact that pharmaceutical companies will do anything they legally (and sometimes illegally) can to maximize revenues.

Studies have shown that the advertisements placed by drug companies in professional journals or distributed directly to physicians are often exaggerated or misleading and do not accurately reflect scientific evidence (Lacasse & Leo, 2005). While physicians deny they are being influenced, it has been shown repeatedly that their prescription preferences are heavily affected by promotional material from drug companies (Moynihan, 2003). Research also suggests that doctors exposed to company reps are more likely to favor drugs over non-drug therapy, and more likely to prescribe expensive medications when equally effective but less costly ones are available (Lexchin, 1989). Some studies have even shown an association between the dose and response: in other words, the more contact between doctors and sales reps the more doctors latch on to the “commercial” messages as opposed to the “scientific” view of a product’s value (Wazana, 2000).

The motivation of psychiatrists to accept the chemical imbalance theory is somewhat more subtle. Starting around 1930, psychiatrists became increasingly aware of growing competition from nonmedical therapists such as psychologists, social workers and counselors. Because of this, psychiatrists have been attracted to physical treatments like drugs and electroshock therapy that differentiate them from nonmedical practitioners. Psychiatry may be the least respected medical specialty (U.S. General Accounting Office report). Many Americans rejected Fruedian talk therapy as quackery, and the whole field of psychiatry lacks the quality of research (randomized, placebo-controlled, double-blind experiments) that serves as the gold-standard in other branches of medicine.

Dr. Colin Ross, a psychiatrist, describes it this way:

“I also saw how badly biological psychiatrists want to be regarded as doctors and accepted by the rest of the medical profession. In their desire to be accepted as real clinical scientists, these psychiatrists were building far too dogmatic an edifice… pushing their certainty far beyond what the data could support.”

Of course there are also many “benefits” to going along with the conventional “chemical imbalance” theory, such as free dinners, symphony tickets, and trips to the Caribbean; consultancy fees, honoraria and stock options from the pharmaceutical companies; and a much larger, growing private practice as the $20 billion spent by drug companies on advertising brings patients to the office. Psychiatrists are just human, like the rest of us, and not many of them can resist all of these benefits.

In sum, the idea that depression is caused by a chemical imbalance is a myth. Pharmaceutical ads for antidepressants assert that depression is a physical diseases because that serves as a natural and easy segue to promoting drug treatment. There may well be biological factors which predispose some individuals toward depression, but predisposition is not a cause. The theory that mental disorders are physical diseases ignores the relevance of psychosocial factors and implies by omission that such factors are of little importance.

Stay tuned for future articles on the psychosocial factors of depression, the loss of sadness as a normal response to life, and the branding of new psychological conditions as a means of increasing drug sales.

Recommended resources

  • Blaming the Brain, by Elliot Valenstein Ph.D.
  • Rethinking Psychiatric Drugs, by Grace Jackson M.D.
  • America Fooled: The truth about antidepressants, antipsychotics and how we’ve been deceived, by Timothy Scott Ph.D.
  • The Loss of Sadness, by Alan Horwitz and Jerome Wakefield
  • The Myth of the Chemical Cure, by Joanna Moncrieff

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magnifying glassI’d like to thank everyone for their comments, both online and “offline” about my recent “Placebos as Effective as Antidepressants” article. Some very good questions were raised in a comment from Stephan, author of the highly recommended Whole Health Blog that I would like to address in today’s article.

The tricky thing about doing scientific research, as I explained in last week’s article, is that conflicts of interest between doctors, researchers and pharmaceutical companies have become so prevalent that the results of even studies published in prominent, peer-reviewed journals cannot be taken at face value.

One must ask: was the study designed properly? Do the author’s conclusions match their own data? Have the authors reported all of the relevant results? Who funded the study, and what role did they have in choosing the subjects, overseeing the methodology and publishing the results?

When looking at a body of research, one must also consider whether there are unpublished studies on the topic and what the effect of those studies might be. This is particularly true in the case of antidepressants, where it has been estimated that approximately 23% of studies have not been published. Why? Because those studies had even less favorable results than those studies that have been published, and the drug companies who paid for them are under no legal obligation (currently – hopefully this might change in the future) to publish study results.

With that in mind, let’s consider Stephan’s comment and each of the points he brings up in turn:

“I fully agree with you about the “chemical imbalance” thing; it’s incredibly dense. They try to spin it like you were born with depression and there’s nothing you can do about it but take a drug. I have a friend who’s into mood disorder research and I’ve talked to him about that meta-analysis showing no significant effect of ADs.

First of all, he has no dog in the fight because his interest in mood disorders is purely academic. I can vouch for his lack of bias toward antidepressants. Here’s what he told me. Basically, what we call “depression” is actually a collection of related disorders. Antidepressants only work on a subset of them.

There are “responders” and “non-responders” in any group of people who receive antidepressants. For responders, antidepressants can be very effective. When you do a meta-analysis where you’re averaging everyone with “depression” together, the effect of an antidepressant will be small or nonexistent because of the heterogeneity. So this is a problem with saying that antidepressants aren’t effective based on that analysis.

I don’t have a problem believing that antidepressants work for some people. They certainly work in animal models of depression, where there is no placebo effect. I don’t think we should banish them from planet Earth. But I do think the fact that we use them so much points to a bigger problem that we should be addressing by other means.”

I want to thank Stephan again for his comment and for raising these important issues.

Let’s start with the parts that I agree with. Certainly, depression has become so broad a term that some have argued that it is an essentially meaningless clinical designation. Unlike other conditions that have measurable physiological markers, people that are diagnosed as depressed do not usually have any features that categorically distinguish them from other people. The sorts of problems that are diagnosed as depression can very considerably depending upon which diagnostic criteria are used, the interpretation of those criteria, and cultural and professional attitudes.

In their book The Loss of Sadness, Horwitz and Wakefield point out that the diagnosis of depression has now come to include transient and completely appropriate responses to life such as sadness after the passing of a loved one, disappointment after the loss of a job or anxiety about financial troubles. They argue, very convincingly, that the DSM IV criteria for depression do not adequately distinguish between what they call “normal sadness” and depression, and the result has been the almost complete medicalization of our emotional response to life. I will be writing an article on this very soon, as I believe it’s a critical perspective to understand in our exploration of depression and antidepressants.

Secondly, I certainly cannot argue with the statement that “antidepressants work for some people”. However, the important questions to ask in relation to that statement are:

  • Why do antidepressants work
  • How do antidepressants work?
  • Whom do they work for?

Why are these questions important? Because if it turns out that antidepressants do not have any specific drug effects (raising serotonin, for example), and work only because people expect or desire them to work (like placebos), or because of non-specific drug effects (such as sedation or stimulation), then the logic behind prescribing antidepressants at all becomes quite tenuous to say the least – especially when their side effects and risks are taken into consideration.

Now let’s consider each point in turn.

“Basically, what we call “depression” is actually a collection of related disorders. Antidepressants only work on a subset of them. There are “responders” and “non-responders” in any group of people who receive antidepressants. For responders, antidepressants can be very effective. When you do a meta-analysis where you’re averaging everyone with “depression” together, the effect of an antidepressant will be small or nonexistent because of the heterogeneity. So this is a problem with saying that antidepressants aren’t effective based on that analysis.”

What Stephan says about the dangers of meta-analysis are true. However, the same danger applies to overestimating the efficacy of antidepressants. There may be some people who are “responders” who have a response to the drug that is significantly higher than placebo; however, there may also be “nonresponders” whose response to the drug was significantly lower than placebo. There is no indication that antidepressants work on a particular subset of people, and no one has identified who this subset is and why they are helped by antidepressants when others are not.

Kirsch’s analysis that antidepressants do not have a clinically meaningful advantage over placebo (“The Emperor’s New Drugs“) has been almost universally accepted within the scientific community. Kirsch’s and his colleagues invoked the Freedom of Information Act to obtain access to the FDA database of controlled trials used in the initial approval for the most popular antidepressants. According to researcher David O. Antonuccio in his article “Antidepressants: A Triumph of Marketing Over Science?“, it is difficult to imagine a database that would offer a more fair opportunity to evaluate the efficacy of antidepressants.

The fact that Kirsch found that antidepressants were no more effective than placebo is surprising, in a way, because these results come from studies that were underwritten and designed by the drug companies themselves under conditions most favorable to the active drug condition. In other words, the deck was stacked from the start in favor of the drugs, and they still didn’t come out ahead.

Since a drug must be shown to be superior to placebo in order to be approved, placebo effects are incredibly annoying to drug companies and they do everything they can to minimize the impact of placebo in their studies. The fact that the FDA allows them to use these techniques is, in my mind, blatant corruption. Consider the following methods used in the studies Kirsch analyzed (and most studies, for that matter):

  1. Placebo washout period: During the first two weeks of the study, everyone is on a placebo. The subjects that respond best to placebo are eliminated from the study. This potentially removes both antidepressant nonresponders (i.e. those that were on an antidepressant before the study starts who get better when they are taken off of it) and placebo resopnders (i.e. those that are not on antidepressants before the study and who respond to placebo). Imagine the converse: an antidepressant washout procedure that eliminates all of the antidepressant responders before a study begins! Such a procedure would surely be considered bias.
  2. Penetration of the blind: the double-blind in these studies (where neither the patients nor doctors are supposed to know who is taking the drug and who is taking the placebo) is likely to be unintentionally broken because of the pattern of side effects in the active and inactive drug conditions (Greenberg & Fisher, 1997). When efforts are made to ensure the integrity of the blind, drug effects are diminished. For example, a recent review of the Cochrane database of antidepressant studies using “active placebos” (making side effects more difficult to detect) found very small, non-significant differences between drug and placebo, suggesting that trials using inert placebos overestimate drug effects (Moncrieff, Wessely & Hardy, 2001)
  3. Replacement of non-responders: at least six of the studies Kirsch reviewed (of 38) allowed replacement of nonresponders. This means that during the first two weeks of the study, those that were not responding to the drug were removed from the study!
  4. Use of sedative medication: Most studies allowed the prescription of a sedative concurrent with the antidepressant. Since other studies have shown that sedatives are as effective in treating depression as antidepressants, how can we possibly know whether the antidepressant effect obtained (if there was one) in these studies was due to the antidepressant drug or the sedative? There are at least 6 points on the 52-point HAM-D scale that the doctors use to determine whether a patient is depressed or not that are related to sleep and favor medications with sedative properties. Since the mean difference between patients taking drugs and patients taking placebos in the studies Kirsch analyzed was only 2 points, it is entirely possible that this small difference is only due to the effects of the sedatives used in the studies and has nothing to do with a true antidepressant drug effect.
  5. Reliance on clinician ratings: Given that patients tend to report smaller differences than clinicians (Moncrieff, 2001) one certainly wonders how the pattern of results would change using self-report measures like the Beck Depression Inventory.

Frankly, considering the bias against placebo described above, it is simply amazing that placebo still nearly matched the effects of the drug. Imagine what the results might look like if the trials had been performed without these “anti-placebo” measures!

Also, Kirsch et al. pointed out that the overall active drug effects may have been further inflated because mean results were not reported from several studies that found nonsignificant differences between placebo and active drugs.

The advantage to using the FDA database for analysis is considerable. It contains all of the data from initial trials, published or not, and therefore is not subject to the usual publication bias. (As I mentioned earlier in the article, drug companies simply don’t publish negative results. This is known as the “file drawer” phenomenon, since they probably just stuff those studies in some file drawer hoping they will never be found). Antidepressants are significantly more effective than inert placebos in about two-thirds of published trials. However, in the FDA database which includes unpublished trials, Kirsch found that medication outperformed placebo less than half of the time (in 20 of 46 trials).

Although Kirsch’s study is a meta-analyses, he is also looking directly at the results of individual trials. When less than half of individual trials show any advantage for the active drug over placebo, one must really wonder whether these drugs have any specific “antidepressant” effects.

Now on to the next point.

“I don’t have a problem believing that antidepressants work for some people. They certainly work in animal models of depression, where there is no placebo effect.”

Actually, it’s not the case that antidepressants work in animal models. According to Joanna Moncrieff in her book The Myth of the Chemical Cure, it is rarely mentioned that all animal models of depression produce variable results according to where they are conducted. “In other words,” she says, “they are unreliable.” In addition to this, they fail to select specifically for antidepressants and responses are obtained with drugs that are not generally considered to be antidepressants (i.e. amphetamines, opiates, antihistamines, antipsychotics, atropine, pentobarbital, zinc and antibiotics).

Also, the SSRIs (the most popular class of antidepressant drugs) typically fail to have any response in the forced swim test, which is one of the most common antidepressant screening tests. In this test, rats are placed in a tank of water from which they cannot escape. The time until they give up trying to escape is measured, on the assumption that the state of giving up is akin to depression. It is thought that antidepressants should prolong the time to giving up. However, the SSRIs have no such effect.

Finally, other tests for depression also frequently show that non-antidepressant drugs (sedatives, stimulants, antihistamines, etc) yield “false positive” results.

“I don’t think we should banish them from planet Earth. But I do think the fact that we use them so much points to a bigger problem that we should be addressing by other means.”

I’m not so sure we shouldn’t banish them from planet Earth, to tell you the truth.

Longitudinal follow-up studies (which study the effects of antidepresants over the long term – not just the 6-8 week periods the clinical trials look at) show very poor outcomes for people treated for depression both in the hospital and in the community, and the overall prevalence of depression is rising despite increased use of antidepressants (Moncrieff & Kirsch, 2006). Two studies that assessed outcome in depressed patients treated with and without drugs found that people prescribed antidepressants had a slightly worse outcome than those not prescribed them, even after baseline severity had been taken into account (Brugha TS et al, 1992; Ronalds C et al., 1997). No comparable studies exist that show a better outcome in people prescribed antidepressants.

Outside short-term randomized clinical trials there is virtually no evidence that antidepressants have changed the outcome of depression. The evidence that does exist suggests that they may have possibly made it worse. Depression is more common today than before antidepressants were introduced and the outcome has not improved. Epidemiological trends show that the more antidepressants are prescribed, the more prevalent depression is. Sharply rising levels of antidepressant prescribing since the 1990s have been accompanied by increased prevalence of depressive episodes (Patten 2004) and by rising levels of sickness absence for depression (Moncrieff & Pomerleau 2000).

Finally, there is a growing body of research suggesting that antidepressants worsen the chronicity, if not severity, of depression in many patients. Even relatively short-term exposure to antidepressants has been shown to cause chemical and even anatomical changes in the body and brain that could predispose patients to further depressive episodes (Jackson, “Rethinking Psychiatric Drugs“)

Some might argue that antidepressants are important to stave off suicide in very depressed patients. However, there is no evidence that antidepressants reduce the risk of suicide or suicide attempts in comparison with a placebo in clinical trials (Kahn et al. 2000). In fact, rates have actually increased in some age groups and in some countries despite increased antidepressant prescribing (Moncrieff & Kirsch 2006), and when antidepressant trials have been re-analyzed to compensate for erroneous methodologies, the SSRIs have consistently revealed a risk of suicide (completed or attempted) of between two to four times higher than placebo (ackson, “Rethinking Psychiatric Drugs“)

And we haven’t even talked about side effects yet! Since this article is already very long, I’ll save that for another day. Suffice to say that these are not harmless drugs and the side effects can be severe and potentially fatal.

So I ask you, fair readers, when you add all of this up, should doctors continue to prescribe antidepressants? Let’s see what researchers who have been studying antidepressants and depression for decades have to say:

“The SSRIs produce no effects that look likely to be useful in depression. They cause unpleasant agitation in a proportion of patients and, although it is difficult to prove conclusively, an increase in suicidal and violent tendencies may be associated with this effect. Therefore, I can think of no goo reason to prescribe them at all.” – Joanna Moncrieff, 2008

Moncrieff has actually suggested that the term “antidepressant” is a misnomer, because the drugs have not been demonstrated to have a consistent and specific effect against depression.

“There is no doubt that antidepressants have a biochemical impact on the brain, but the valence of that impact is open for considerable debate, and whether it corrects a chemical imbalance is in grave doubt… One day we may look back and marvel at the stroke of marketing genius that led to calling these medications antidepressants in the first place. Kirsch et al. have demonstrated that just because a pill is called an antidepressant, it doesn’t necessarily make it so.” – David Antonuccio, 2002

If antidepressant drugs were the only option for treating depression, one might still be able to make an argument for their use in spite of their lack of efficacy and risks. However, it has repeatedly been shown that aerobic exercise, light therapy, Cognitive Behavioral Therapy, St. John’s Wort, bibliotherapy (prayer) and perhaps acupuncture (more studies are needed) are just as effective for treating depression as antidepressants – with few, if any, adverse effects. In fact, in the case of exercise many of the side effects produced are beneficial (e.g. better overall health and wellness).

Considering that antidepressants are likely no more effective than placebos, have not improved (and perhaps worsened) long-term outcomes, may increase the risk of suicidal and violent behavior and have significant many other significant side effects and risks, including potentially permanent changes in the brain which predispose patients to further depression… and considering that there are well-established alternatives that are just as effective, if not more so, in treating depression with almost no adverse effects and significantly fewer costs, I see no compelling reason to continue prescribing antidepressants.

Obviously many other people are posing this question, particularly in the medical community. Kirsch’s research has been so widely accepted that the debate has not centered around his conclusions, but on the implications of those conclusions. Ironically, it has been suggested by more than one commentator that although we now know that antidepressants aren’t effective, we should continue to prescribe them – if only in an attempt to elicit a placebo effect.

Huh? Let me explain. One major reason people respond to placebo in antidepressant trials is that they expect the drug to work. They expect it to work because of all of the promotion they’ve seen, newspaper and magazine articles they’ve read, and personal testimonials they’ve heard. What would happen if it became known that antidepressants are, in fact, not effective and that they could actually make depression worse. Bye bye placebo effect.

So some researchers and doctors have actually suggested that we should go on promoting the delusion that antidepressants are effective so that people who are taking them will continue to believe that they are working, which of course significantly increases the chance that they will work.

If these drugs were not so potentially dangerous and harmful, and if there were not proven alternatives, I could almost go along with this deception – although it does raise some very interesting ethical questions. However, the drugs are potentially dangerous and harmful, and there are proven alternatives, so I cannot agree with this approach.

In closing, I just want to remind anyone who is currently taking an antidepressant and thinking about stopping that it is essential you do so under your doctor’s supervision. You will have to gradually taper off of your medication – do not stop abruptly!

As always, I welcome your comments and questions.

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money in pill bottleI’m preparing for an upcoming presentation in September called “The (Hidden) Truth About Antidepressants”, so I will be writing frequently about issues related to the definition, cause and treatment of depression in the weeks to come.

Much of what I write may challenge your current beliefs and contradict what you’ve heard about depression and antidepressants. My hope is that today’s post about the influence of the pharmaceutical industry on doctors, researchers and patients will inspire you to re-examine what you’ve been told so far and approach everything you hear in the future with a “healthy skepticism”.

The truth is that all of our beliefs about depression have been tainted, quite intentionally, by the more than $20 billion spent each year by pharmaceutical companies to promote their drugs (an amount greater than the gross domestic product of all but 70 of the world’s richest nations). In 2000, the pharmaceutical industry had a combined lobbying and campaign contribution budget of $200 million – larger than any other industry (Wayne & Peterson, 2001). The industry has 625 registered lobbyists, more than there are members of congress (Wayne & Peterson, 2001). The industry also underwrites about 70% of clinical drug trials in the United States (DeAngelis et al., 2001).

Consumer Reports has detailed the marketing strategies used by drug companies, including:

  • giving free samples and information to doctors
  • advertising in medical journals
  • using “ask your doctor” media advertisements aimed directly at the consumer (the U.S. and New Zealand are the only two countries that allow this)
  • sponsoring promotional dinner meetings with substantial gifts or even cash provided for attendees
  • paying consultants to speak at scientific meetings where it is possible to circumvent FDA guidelines that require disclosure of side effects
  • funding only those research projects that have a high likelihood of producing favorable results for a particular drug company’s product
  • terminating negative studies before they are ready for publication
  • not publishing studies with negative results
  • offering to pay journalists to cover their products
  • helping to fund patient advocacy and other public interest groups so the consumer group appears to be publicly carrying the banner of a particular drug

How can we possibly rely on information that is so inexorably intertwined with corporate interests? Corporations have very little motivation to share information that could harm sales of their products, as they are required by law to maximize profits for their shareholders. On the contrary, they have much incentive to do everything in their power to suppress such information. Several studies have shown that researchers who produce data that is contrary to the interests of the pharmaceutical industry risk legal, professional, or even personal attack – directly or indirectly financed by the industry. (Bosley, 2002; Healy, 2002; Monbiot, 2002).

As researcher David Antonuccio points out in his excellent article Antidepressants: A Triumph of Marketing over Science?:

“Company-sponsored experts, whether they are researchers or educators, are by definition company employees. They will be retained only if they offer consistently favorable treatment to the company’s products. It could be argued that their efforts on behalf of antidepressants often fit more properly under the rubric of marketing or advertising, not science or education.”

Clinical trials are the basis of approval of new drugs by the FDA, but their reliability is seriously in doubt because of three major flaws: conflicts of interest on the part of investigators; inappropriate involvement of research sponsors in their design and management; and publication bias in disseminating their results. (Quick, 2001)

The situation has become so dire that in September of 2001 the editors of 13 leading medical journals published a joint editorial in which they said:

“Research contracts should give the researchers a substantial say in trial design, access to the raw data, responsibility for data analysis and interpretation, and the right to publish”

Huh? Wouldn’t you expect researchers to have these rights already? In many cases, they don’t.

The editor of the prestigious New England Journal of Medicine argued in a separate editorial that the editors didn’t go far enough in their rebuke:

“The entire system of clinical investigation is driven by profit. We are seeing the corruption of a system of research that used to have high ideals and be clearly in the public interest.”

The conflicts of interest between researchers and drug companies is bad enough. But what’s even more distressing is that many doctors do not even read the research to learn about the drugs they are prescribing. Jerry Avorn, a Harvard Medical School professor and drug researcher is a leading authority on how physicians are educated about new drugs. He acknowledges that most physicians have only minimal knowledge about drug studies. Instead, Dr. Avorn has this to say about where most physicians get their knowledge about drugs:

“Pharmaceutical marketing is about the most important source of knowledge about new drugs for most physicians, and a major form of continuing education as well.”

There are now over 90,000 pharmaceutical reps walking the halls of medical offices around the U.S. Since there are less than 600,000 office-based doctors in the U.S. today, there is approximately one full-time drug rep for every six physicians. The drug reps bring free food for office staff, free samples for distribution to patients, free pens, free textbooks and other free gifts. They are also sometimes authorized to provide free vacations for physicians who would enjoy spending a weekend with other physicians in places like Hawaii or the Caribbean hearing the latest “research” on the effectiveness of a drug. In 2006, the pharmaceutical industry spent $2 billion on these types of events alone.

Does all of this advertising and promotion actually influence doctors? You bet it does. A government report found that in just one year the most heavily advertised drugs had prescription increases of 25% (U.S. General Accounting Office, 2002). There is even a formula that generally applies to drug advertising: each dollar spent on advertising increases sales by $4.

Even more discouraging than the influence of drug companies on doctors is the influence of patients who’ve been subjected to drug company advertising on doctors! A study published in the Journal of the American Board of Family Practitioners reported that 49% of patient requests for drugs or other requests prompted by “direct-to-consumer” advertising were not clinically appropriate. Yet 7 out of 10 times, physicians gave into the requests. (And that is by their own admission; there is likely a percentage of physicians who do not want to admit they write prescriptions or order tests on the basis of patient requests.)

The influence of advertising on doctors and patients is particularly relevant in the case of antidepressants. By a wide margin the largest amount spent on advertising by drug companies was on antidepressant promotion – a whopping $367 million dollars per week!(U.S. General Accounting Office, 2002) In fact, it appears that DTC advertising may be the single most effective way a drug company can increase the number of people who are diagnosed with depression and then will begin taking antidepressants (Donohue, 2004).

I could go on, but I think you get the point. As consumers and patients we simply cannot rely on profit-driven drug companies to give us accurate information about their products. And unfortunately, because of the massive conflicts of interest that exist between researchers, physicians and the pharmaceutical industry – we cannot necessarily rely on our doctors or even scientific studies to show us the way.

Luckily for us, there are still studies being done by independent researchers and those brave enough to risk the ire of the drug companies that we can turn to for honest, unbiased data. Unsurprisingly, these studies often have very different results than those sponsored by the industry. Thanks to the Freedom of Information Act, some researchers have even been able to access the studies done by the drug companies that they never published (obviously the ones that were least favorable to their drugs).

When these independent and unpublished studies are analyzed, a very different picture of depression and the efficacy of antidepressants begins to emerge.

Contrary to popular belief:

  1. There is no evidence that depression is caused by a “chemical imbalance” (which is the rationale behind prescribing antidepressants).
  2. Recent meta-analyses of the research data show that antidepressants have no clinically meaningful advantage over placebo. Therefore, the term “antidepressant” is a misnomer and should be abandoned.
  3. Poor study design may account for the small degree of superiority shown over placebo
  4. Claims that antidepressants are more effective in more severe conditions have little evidence to support them.
  5. Antidepressants have not been shown to affect the long-term outcome of depression or suicide rates.
  6. It is now recognized that SSRIs (the most widely used class of antidepressants) increase the risk of suicidal behavior in children and adolescents, and there is legitimate concern that the same is true for adults.
  7. Given doubt about their benefits and concern about their risks, current recommendations for prescribing antidepressants should be reconsidered.

You might be shocked by some of these statements. Though I was already very skeptical about antidepressants before beginning this research, I myself have been blown away by the complete lack of evidence supporting the theory that depression is a biological disease and the very strong evidence that antidepressants are no more effective than placebo.

I’ll be writing in more detail about several of the points to come in the coming weeks, so please stay tuned!

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pills on spoon

THS reader Chad sent in this question:

Antidepressants – effective or placebo?

The use of antidepressant medication has become so widespread and commonly accepted that it seems almost sacrilegious to question it. But alas, questioning is the name of the game here at The Healthy Skeptic!

And what do you know? Antidepressants aren’t all they’re cracked up to be. In fact, a recent meta-review of published studies on the efficacy of antidepressant drugs revealed that selective serotonin reuptake inhibitors (SSRIs), which are the most commonly prescribed drugs to treat depression, have no clinically meaningful advantage over placebo.

What that means is that in most of the trials reviewed, patients who took a sugar pill recovered from depression just as often as those who took the active drug. This study may come as some surprise to both physicians and the general public, whose faith in the efficacy of these drugs has led to over 118 million prescriptions in 2007 and over $16 billion in sales.

But should this really come as a surprise? Antidepressant drugs are thought to act by altering levels of brain neurotransmitters; however, it takes several weeks before these changes can be measured. Yet patients often report symptomatic relief within hours or days of receiving an antidepressant.

Available data suggests, in fact, that SSRIs are no more effective than placebos and have considerable adverse effects and risks, including increased suicidality amongst both children and adults. Sapirstein and Kirsch conducted a meta-analysis of 3,000 patients who received either antidepressants, psychotherapy, placebo or no treatment at all. They found that 27% of therapeutic responses were attributable to drug activities, 50% to psychological factors, and 23% to “non-specific” factors. In other words, 73% of the response to the drug was unrelated to its pharmacological activities – and antidepressants may be no better or more specific than placebos.

This of course raises grave questions about why the National Institute for Health and Clinical Excellence (NICE) still recommends that antidepressants should the be first line treatment for moderate or severe depression. Their message is identical to that of the Defeat Depression Campaign in the early 90s, which contributed to the 253% rise in antidepressant prescribing in 10 years.

In a review published in the British Medical Journal in February of 2006, researchers Joanna Moncrieff and Irving Kirsch point out that the NICE recommendations ignore even their own study data. Although the NICE meta-analysis of placebo controlled trials of SSRIs found statistically significant differences in levels of symptoms, these were so small that the effects were deemed “unlikely to be clinically important.”

After analyzing several published studies and reviews, Moncrieff and Kirsch reached the following conclusions:

Summary points

  1. SSRIs have no clinically meaningful advantage over placebo
  2. Claims that antidepressants are more effective in more severe conditions have little evidence to support them
  3. Methodological artifacts may account for the small degree of superiority shown over placebo
  4. Antidepressants have not been convincingly shown to affect the long-term outcome of depression or suicide rates

The response to a drug or placebo in a clinical trial for depression is often measured using the Hamilton rating scale, a multiple choice questionnaire which doctors use to rate the severity of a patient’s condition. The questionnaire rates the severity of symptoms observed in depression such as low mood, insomnia, agitation, anxiety and weight-loss; it is considered to be a highly reliable physician-rated scale and has been reported to be more sensitive than patient-rated scales to drug/placebo differences. (Murray, 1989)

In the NICE meta-analysis, the difference between drug and placebo groups was one point. The most commonly used 17 item version of the Hamilton scale has a maximum score of 52. It is highly unlikely that a difference of one point on a 52-point scale is clinically significant, a fact that the FDA has admitted in memoranda (Laughren, 1998; Leber, 1998) reviewed by Moncrieff and Kirsch.

Other studies have yielded similar results. A study by Khan et al. found a 10% difference in levels of symptoms between placebo and active drugs in two different meta-analyses. In a more recent review, Kirsch et al. invoked the Freedom of Information (FOA) act to obtain access to previously unpublished studies (the drug companies are under no requirement to publish a study they have sponsored if the results don’t suit them). The overall difference between drugs and placebos in that analyses was 1.7 points on the Hamilton scale.

Moncrieff and Kirsch also point out that the Hamilton scale contains seven items concerning sleep and anxiety, with each item on sleep scoring up to six points. Therefore any drug with some sedative properties, including many antidepressants, could produce a difference of two points or more without exerting any specific antidepressant effect.

Follow-up studies that track patients for a significant length of time have also shown very poor outcomes for people treated for depression both in the hospital and in outpatient settings, and the overall prevalence of depression is rising despite increased use of antidepressants. Suicide rates have increased in some groups and some countries, despite increased prescribing of antidepressant, and there are continuing concerns that SSRIs may increase the risk of suicidal behavior in obht cildren and adults.

In children, the balance of benefits to risks in antidepressant treatment is already recognized as “unfavorable”. The analyses performed by Moncrieff and Kirsch strongly suggests that the same is the case for adults, and that the ongoing uncertainty about the possible risk of increased suicidality as well as the adverse effects of antidepressant drugs warrant a “thorough re-evaluation of our current approach” to treating depression.

I couldn’t agree more. One question the authors failed to pose, which I believe to be at the root of the matter, is why are so many more children and adults depressed now than before? You might not be surprised to learn that I have some thoughts about this. But I’ll save them for another post.

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