Personality related differences in response to 5-HT uptake inhibition

Conflicting results on clinical effects of serotonergic drugs gave rise to this investigation on the relationship between depression-related personality factors and effects of the 5-HT uptake inhibitor fluoxetine on psychomotor functions and emotional states. In a double-blind, balanced, crossover design, 24 healthy male subjects divided according to scales of "Experiencing of Stress" and "Neuroticism," were tested with a single dose of 60 mg fluoxetine or placebo. Reaction time and feelings of activation and energy of highly neurotic or stressed subjects were deteriorated by fluoxetine while emotionally stable subjects were improved by the drug. The findings were interpreted in terms of personality related differences in 5-HT neurotransmission and receptor sensitivity.