Monday, July 7, 2008

Depression As Neurodegenerative Disorder

The Boston Globe has a fascinating article about new views on the causes of depression. To summarize, there is a growing consensus that Prozac and other SSRIs do not work by changing brain chemistry, as had been thought. Instead, researchers have realized that the main impact of SSRIs is in re-generating atrophied neurons.
"The best way to think about depression is as a mild neurodegenerative disorder," says Ronald Duman, a professor of psychiatry and pharmacology at Yale. "Your brain cells atrophy, just like in other diseases [such as Alzheimer's and Parkinson's]. The only difference with depression is that it's reversible. The brain can recover."
The interesting thing about SSRIs is that nobody really know why they work. They were developed in response to research showing depressed patients had low levels of serotonin. Why low levels of serotonin led to depression, or how restoring those levels led to recovery have remained mysterious. At some point, everything has to get resolved to physiology. That connection has never been adequately made until this new theory came along.In addition to providing a plausible mechanism for the effectiveness of SSRIs, the new view also takes into account the less obvious symptoms such as sleep disturbance, learning, concentration and memory problems. As someone with severe, chronic depression, I can tell you that the cognitive impairments are far more disabling than the mood problems.For anyone interested in the subject, this is a short but interesting read.
photo from the Boston Globe article.



Another article on Psych Central takes issue with the Boston Globe article, calling the theory another fad. The author points out that several key bits of the article are problematic and illogical. Most persuasively, he argues that depression can't be a neurodegenertive disorder if traditional psychotherapy and cognitive behavioral therapy can work as treatments. These would have no impact on a purely physiological disorder.

The problem with both articles, a bit less so with the Boston Globe one, is that they tend to look at depression as a monolithic condition. My belief, based only on my own experience, is that what we call depression is really a number of different underlying disorders. These disorders have different causes, different impacts on the body and different treatments. The only things they share are a generally similar set of symptoms. This explains why no one treatment helps more than a slight majority of the patients that receive it.

In my case, SSRIs have worked inconsistently, CBT a bit, ECT a bit, psychotherapy a bit, exercise a bit, diet a bit, and mediation a bit. The main ingredient in my recovery so-far has been time. This suggests to me that our understanding of the problem is still elementary.