Depression diversity: Brain studies reveal big differences among i...( ANN ARBOR Mich. - Depressed people m...),Health

ANN ARBOR, Mich. - Depressed people may have far fewer of the receptors for some of the brains feel good stress-response chemicals than non-depressed people, new University of Michigan Depression Center research shows.

And even among depressed people, the numbers of these receptors can vary greatly. Whats more, the number of receptors a depressed person has appears to be linked with the severity of their symptoms - and the chances that theyll feel better after taking a medication.

These preliminary findings, presented Tuesday at the American Psychiatric Associations annual meeting in Washington, D.C., amplify a growing understanding of depression as a condition that affects different people in different ways, and is solidly rooted in genetic and molecular factors that are unique to each individual.

The lead U-M researcher, Jon-Kar Zubieta, M.D., Ph.D., says these new results bolster what other researchers have been finding in recent years.

Theres a substantial amount of biological difference even among people who have major depression, which is just as important as the biological differences between people with depression and people without, he says. The more we can understand about these differences, the better we can address treatment to the individual and have the greatest effect on symptoms.

At the APA meeting, Zubieta presented data from positron emission tomography, or PET, scans of the brains of patients who met the criteria for major depression but had not yet received treatment for it. Those scans were compared with scans of the brains of non-depressed comparison volunteers.

In one group of depressed and non-depressed volunteers, the scans were made using a tracer that can reveal the location and concentration of a particular type of receptor. Called the 5HT1a receptor, it allows brain cells to receive signals from serotonin, a chemical neurotransmitter produced by the brain.

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