Talk therapy and drug therapy both combat major depression, but an imaging study shows that the two treatments have distinctly different effects on specific parts of the brain.
Cognitive behavioral therapy (CBT) changes metabolic activity in the cortex, the thinking brain, to modulate mood states. It works from the top down, altering how people monitor and react to negative emotional stimuli in their environment. Drugs, by contrast, work from the bottom up, modulating neurotransmitters in the brainstem, which drive basic emotional behaviors.
Reporting in the Archives of General Psychiatry, neurologist Helen Mayberg and colleagues at the University of Toronto found that the unique metabolic changes produced by CBT in the cortex reflect newly learned ability to detect troubling emotional stimuli and to keep them out of working memory, where they get amplified by rumination. Such changes may make a relapse of depression far less likely.
The effects produced by both types of therapy point to a larger, complex circuit of depression in the brain. "Our imaging study shows that you can correct the depression network along a variety of pathways," says Mayberg. "Drugs change the chemical balance in the brain through effects at very specific target sites. Cognitive therapy is tapping into a different part of the same depression circuit board."