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In my book Anatomy of an Epidemic, I investigated this puzzle: Why has the number of adults on government disability due to mental illness soared since Prozac's arrival on the market in 1987? Prozac was the first of the "second-generation" psychiatric drugs, and our society's use of these medications has exploded since that time, which presumably should result in a lessening of the burden of mental illness in our society. Yet, from 1987 to 2007, the number of adults on federal disability due to mental illness rose from 1.25 million to 4 million, begging this question: Could our drug-based paradigm of care be fueling this epidemic?
That, of course, is a provocative question, and I spent 260 pages in Anatomy of an Epidemic seeking to answer it. But recently, I came upon two new data sets that, at the very least, add new reason for our society to worry about this question.
I am giving a talk in Iceland later this month, and the organizers of that talk recently sent me a copy of a paper published last year in the Journal of Mental Health, titled "Increased incidence of disability due to mental and behavioural disorders in Iceland 1990-2007." The prescribing of psychiatric medications to the adult population steadily increased during this period, and so too the disability numbers. On a per-capita basis, the number of adults going onto disability annually due to mental and behavioural disorders more than doubled from 1990 to 2007. This was so even though there was "little evidence for a similar increase in the population prevalence of mental and behavioural disorders," the researchers noted.
In other words, the percentage of the population experiencing a psychiatric problem had remained the same, but the percentage ending up on disability had more than doubled. Iceland's experience is similar to ours.
I stumbled upon another data set of this sort during a recent psychiatry Grand Rounds at Massachusetts General Hospital in Boston. I had been asked to present at that Grand Rounds, and then Dr. Andrew Nierenberg "shared his perspective" about my book. (Anyone interested in reading more about his critique of Anatomy of an Epidemic, and my replies to it, can go here.) After I returned home from that event, I realized that Dr. Nierenberg had provided data in his presentation that provided a way to assess the link between the number of people treated and disability rates.
In his presentation, Dr. Nierenberg showed survey data that had found that 30% of the adult population in the U.S. suffered from a psychiatric disorder in 1990-92, and that this percentage was basically the same in 2001-2003. There was no increase in the prevalence of mental disorders during this 13-year period. However, the percentage of those with a disorder who were treated rose from 20.3% in 1990-1992 to 32.7% in 2001-2003. Now if you look up census data for the number of adults in 1990 and 2003, and do the relevant math (based on the survey data that Dr. Nierenberg cited,) you find that the number of people treated rose from 11.16 million adults in 1990 to 21.77 million in 2003. And what happened to the disability numbers during this period? The number of adults receiving SSI or SSDI due to mental illness more than doubled, from 1.47 million people in 1990 to 3.25 million in 2003.
There is one other way to parse this data. In 1990, there were 55 million adult Americans with a "psychiatric disorder," (based on the prevalence data cited by Dr. Nierenberg.) There were 1.47 million adults who were collecting a federal disability check that year due to mental illness. Thus, one in every 37 adults (2.7%) with a psychiatric disorder in 1990 was on long-term disability.
By 2003, the adult population had increased, and thus although the prevalence of psychiatric disorders had remained the same as in 1990, the number with a psychiatric disorder had risen to 66 million. There were 3.25 million adults who were collecting a federal disability payment that year due to mental illness, or one in every 20 with a psychiatric disorder (5%). Thus, during this period of markedly increased treatment, the percentage of those with a psychiatric disorder who ended up on long-term disability rose from 2.7% to 5%.
These data do not prove that psychiatric drugs increase the risk that a person with a "psychiatric disorder" will end up on long-term disability. But they sure beg the question of whether that is so, and that is a question that I think our society would want to answer.
