http://goo.gl/tg05GR
A drug being studied as a fast-acting mood-lifter restored pleasure-seeking behavior independent of - and ahead of - its other antidepressant effects, in a National Institutes of Health trial. Within 40 minutes after a single infusion of ketamine, treatment-resistant depressed bipolar disorder patients experienced a reversal of a key symptom - loss of interest in pleasurable activities - which lasted up to 14 days. Brain scans traced the agent's action to boosted activity in areas at the front and deep in the right hemisphere of the brain.
"Our findings help to deconstruct what has traditionally been lumped together as depression," explained Carlos Zarate, M.D., of the NIH's National Institute of Mental Health. "We break out a component that responds uniquely to a treatment that works through different brain systems than conventional antidepressants - and link that response to different circuitry than other depression symptoms."