Sunday, July 03, 2011

The Illusions of Psychiatry?

Marcia Angell recently wrote a two-part article in the New York Review of Books containing numerous criticisms of the field of psychiatry. Angell's article contains a review of three books: The Emperor's New Drugs by Irving Kirsch; Robert Whitaker's Anatamoy of an Epidemic; and Daniel Carlat's Unhinged. I am interested primarily in discussing Irving Kirsch's claim that psychiatric drugs are no more effective than placebos, and Robert Whitaker's criticisms of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR).

Irving Kirsch gives two main arguments in defense of his claim that psychiatric drugs are no more effective than placebos. The first is that, when one takes into account all of the clinical trials conducted by pharmaceutical companies--not just those successful trials which are more likely to get published in medical journals--placebos are 82% as effective as the six psychiatric drugs approved by the FDA between 1987 and 1999 (Prozac, Paxil, Zoloft, Celexa, Serzone, and Effexor). This result shows that the drugs are at best not much more effective than placebos.

Kirsch's second main argument is that the apparent extra degree of effectiveness of psychiatric drugs over placebos is actually due to an enhanced placebo effect. Kirsch notes that the psychiatric drugs believed to be effective all have noticeable side effects. The problem is that the presence of noticeable side effects undermines the double-blind control put on the trials. Because the actual drug causes noticeable side effects, and because a placebo does not cause side effects, it is possible for a patient to figure out if he has been given the actual drug and not a placebo. The fact that the medications appear to work better in treating severe cases of mental illness may simply be due to the fact that higher doses tend to be given in severe cases, and the side effects are therefore more noticeable. When side effects are noticeable, it becomes more likely that the patient believes he is receiving the actual drug, and thus more likely that the placebo effect occurs. Thus, psychiatric drugs may out-perform placebos (by a small margin) just because they are better at producing a placebo effect.

Crucial to Kirsch's analysis is data from unpublished studies conducted by drug companies on the effectiveness of the psychiatric drugs in question. Kirsch had to use the Freedom of Information Act to get the FDA to release the data. The FDA requires drug companies to give them data on all of the trials conducted by drug companies--not just selected trials or trials which have been published in medical journals. However, the FDA only requires that two of the trials show clinical effectiveness before giving a drug approval. This is problematic, because drug companies can conduct any number of trials in an attempt to show effectiveness, and even if two of the trials do show effectiveness, these two trials do not necessarily reflect the overall data set. The FDA basically allows the drug companies to cherry-pick trials in determining the effectiveness of a drug.

The second part of Angell's article contains a discussion of Robert Whitaker's criticisms of the DSM-IV-TR and its predecessors. Angell portrays the DSM as largely the creation of one man, Robert Spitzer, a former professors of psychiatry at Columbia University. Angell portrays Spitzer as not giving sufficient weight to views other than his own in producing the DSM; Spitzer both hand-picked the 15-member task force who developed the DSM, and said in an interview in 1989 that "I could just get my way by sweet-talking and whatnot," for example. Angell claims that Spitzer's work on the DSM was biased by his goal of producing a diagnostic manual that would facilitate the use of psychiatric drugs to treat mental disorders. Finally, Angell notes that the DSM is free of citations to back up its decisions regarding the classification of and diagnostic criteria for mental disorders, which undermines its claims to represent an informed scientific consensus.

I would add that the DSM is inherently problematic in that its definitions of mental disorders and diagnostic criteria are generally symptom-based. My understanding is that it is preferable, perhaps essential, for a disease to be identified and diagnosed not on the basis of symptoms alone (especially behavioral symptoms, which are often hard to reliably assess), but rather on the basis of measurable physical indicators--such as the presence of antibodies in the blood in the case of a viral infection. The criteria proposed by the DSM seem to at best identify syndromes which consist of characteristic clusters of abnormal behaviors, and not true diseases with specific etiologies and biological markers.

I don't know enough about psychiatry to say whether Angell's article gives an accurate picture of the state of psychiatry as a whole, or whether she is exaggerating the problems the discipline faces. Nevertheless, I think she presents enough information to give reason for concern. I do think that psychiatry's medial model has great potential to help people with mental disorders, but it may be that this potential has been realized even less than we think.
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