Brain serotonin-2 receptors in acute mania.

BACKGROUND Although 5-hydroxytryptamine (5-HT) has been implicated in mania, the precise alterations in the 5-HT system remain elusive. AIMS To assess brain 5-HT2 receptors in drug-free individuals experiencing a manic episode in comparison with healthy volunteers using positron emission tomography (PET). METHOD Participants (n = 10) with DSM-IV bipolar I disorder-manic episode and healthy controls (n = 10) underwent [18F]-setoperone scans. The differences in 5-HT2 receptor binding potential between the two groups were determined using statistical parametric mapping (SPM) analysis. RESULTS Age was a significant correlate with 5-HT2 receptor binding potential with a similar magnitude of correlation in both groups. The SPM analysis with age as a covariate showed that the individuals with current mania had significantly lower 5-HT2 receptor binding potential in frontal, temporal, parietal and occipital cortical regions, with changes more prominent in the right cortical regions compared with controls. CONCLUSIONS This study suggests that brain 5-HT2 receptors are decreased in people with acute mania.