Eric Kandel on biological psychiatry

The new (?) science of mind:

In a recent study of people with depression, Professor Mayberg gave each person one of two types of treatment: cognitive behavioral therapy, a form of psychotherapy that trains people to view their feelings in more positive terms, or an antidepressant medication. She found that people who started with below-average baseline activity in the right anterior insula responded well to cognitive behavioral therapy, but not to the antidepressant. People with above-average activity responded to the antidepressant, but not to cognitive behavioral therapy. Thus, Professor Mayberg found that she could predict a depressed person’s response to specific treatments from the baseline activity in the right anterior insula.

These results show us four very important things about the biology of mental disorders. First, the neural circuits disturbed by psychiatric disorders are likely to be very complex.

Second, we can identify specific, measurable markers of a mental disorder, and those biomarkers can predict the outcome of two different treatments: psychotherapy and medication.

Third, psychotherapy is a biological treatment, a brain therapy. It produces lasting, detectable physical changes in our brain, much as learning does…

Matthew State, at the University of California, San Francisco, has discovered a remarkable copy number variation involving chromosome 7. An extra copy of a particular segment of this chromosome greatly increases the risk of autism, which is characterized by social isolation. Yet the loss of that same segment results in Williams syndrome, a disorder characterized by intense sociability.

This single segment of chromosome 7 contains about 25 of the 21,000 or so genes in our genome, yet an extra copy or a missing copy has profound, and radically different, effects on social behavior.

The second finding is de novo point mutations, which arise spontaneously in the sperm of adult men. Sperm divide every 15 days. This continuous division and copying of DNA leads to errors, and the rate of error increases significantly with age: a 20-year-old will have an average of 25 de novo point mutations in his sperm, whereas a 40-year-old will have 65. These mutations are one reason older fathers are more likely to have children with autism and schizophrenia.

The State paper is here. Of course, we should all remember the nature vs nurture debates: the expression of these genes are often influenced by the (social) environment.  I would argue that this intersection will be the most fruitful line of medical research in the coming decades.

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