SEROTONIN DYSFUNCTION DISORDERS - A BEHAVIORAL NEUROCHEMISTRY PERSPECTIVE

The spectrum of efficacy of the serotonin selective reuptake inhibitor (SSRI) antidepressant drugs continues to expand. In fact, no psychiat ric syndrome seems to worsen with these agents, and few studies fail t o demonstrate clinical improvement in some patients, regardless of any nosologic nicety, such as precise DSM diagnosis. This suggests that t he biological rubric of psychopathology is dimensional rather than cat egorical. New research using in vivo microdialysis shows differences i n neurochemistry among SSRIs, wherein fluoxetine blocks reuptake of do pamine and norepinephrine, as well as serotonin, in medial prefrontal cortex, and fluvoxamine has a relatively more selective neurochemical profile. In the animal model of learned helplessness, which is a biobe havioral model for stress-induced anxiety causing depression, the SSRI s including fluvoxamine prevent helplessness. From these and other dat a, a neurotransmitter balance theory of biopsychopathology is formulat ed. In this hypothetical construct, dopamine, norepinephrine, and GABA modulate thought, anxiety, and mood, respectively. Serotonin is a sta bilizing agent, which assists in returning the mind to its homeostatic setpoint.