Psychiatric disorders: Why two is better than one.

摘要

Many depression and anxiety disorders are most effectively treated with a combination of psychotherapy and antidepressant drugs. The biological basis for this observation is not well understood, but Castren and colleagues now show that the antidepressant fluoxetine increases synaptic plasticity in the amygdala and thereby facilitates long-lasting fear extinction. The authors used a Pavlovian fear conditioning-extinction paradigm, in which mice are exposed to a painful stimulus together with a neutral conditioned stimulus (a tone). When mice are subsequently exposed to the tone alone they show a fear response, but repeated exposure to the tone in a different context can extinguish this response - reminiscent of exposure therapy in humans with anxiety disorders. Importantly, extinction is not permanent: the fear response can recover spontaneously and can also be re-induced by exposing the mice to the tone in the original, conditioning context.