Which came first, the mental illness or the drug? While in other areas of medicine this is a no-brainer (no pun intended), some argue that certain psychiatric conditions are created and classified because of the effects particular drugs have on the body, and not the other way around.

Three new books, reviewed in Dr. Marcia Angell's article "The Epidemic of Mental Illness: Why?" in The New York Review of Books, raise startling possibilities about the truth behind the explosion of prescriptions of pharmaceutical treatments for mental illness. (Dr. Angell, by the way, was the first woman to ever be editor-in-chief of the prestigious New England Journal of Medicine).
All of the authors of the new books agree on two thought-provoking viewpoints:
1. Our understanding of categories of mental illness and their treatments has been influenced by drug companies, through both legal and illegal marketing.
2. Mental illness is not caused by chemical imbalances in the brain.
These views, however controversial, are documented well, Angell says.
For instance, even though the goal of psychoactive drugs is to alter levels of neurotransmitters - brain chemicals - which affect mood, scientists have not found good evidence that it's the chemicals themselves that cause the mental illness. Before treatment, neurotransmitter function seems to be normal, they say.
"By this same logic one could argue that the cause of all pain conditions is a deficiency of opiates, since narcotic pain medications activate opiate receptors in the brain," writes Daniel Carlat, author of "Unhinged: The Trouble With Psychiatry - A Doctor’s Revelations About a Profession in Crisis."
So if drugs don't treat the cause of mental illness, what are they doing? Irving Kirsch argues in "The Emperor’s New Drugs: Exploding the Antidepressant Myth" that antidepressants work merely because patients believe they work, and the pills' side effects reinforce that belief.
As I wrote earlier this month, the placebo effect is the idea that a sham medical treatment, with no inherent healing properties, can sometimes operate as if it were an actual drug in alleviating pain and changing blood pressure, digestion and other involuntary functions. The more complex and involved the fake treatment, the more effective it's likely to be.
So keep that in mind when you consider that, according to Kirsch's research on Food and Drug Administration reviews of clinical trials of antidepressants, placebos were about 82% as effective as the drugs. And non-antidepressant treatments such as sedatives and opiates were just as effective. In fact, he found that "nearly any pill with side effects was slightly more effective in treating depression than an inert placebo," Angell writes. Kirsch speculates that, in fact, the side effects themselves are what convince patients that their antidepressants are working, and lead to them saying they feel less depressed.
Our CNNHealth.com mental health expert - Dr. Charles Raison, a psychiatrist at Emory University School of Medicine - says there is some truth to the idea that antidepressants work at least in part by the placebo effect, and science has borne that out. And that's not necessarily a bad thing, as physicians can harness this effect - for instance, in terms of the doctor-patient relationship itself being therapeutic - he says. But in patients with more severe depression, the placebo effect diminishes, so the drug must be doing something. You could even look at it like this: antidepressants may potentiate the placebo effect.
"Antidepressants are not perfect, but they definitely have saved many people’s lives," he says.
And if the myth of the chemical imbalance suggests that depressed people simply need more or less of certain brain chemicals, that's right, Raison says: "It’s pretty clear that depression is not like you’re running out of gas." But, of course, all emotions and thoughts are generated by physical interactions in the brain and the body, so at its core, depression is indeed a biologically based disorder. The brain is obviously quite complex, and antidepressants seem to help reset and recalibrate systems in the brain to help you feel better.
Angell will address the "wonder drug" popularity of mental illness treatments in the second part of her series.