Serotonin concentrations and turnover in brains of depressed suicides

5-Hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) concentrations and 5-HT turnover (5-HIAA/5-HT) were determined in 6 brain regions from 19 suicide victims in whom a retrospective diagnosis of depression was established, and 19 age- and sex-matched control subjects. Thirteen of the suicides were free of psychoactive drugs at the time of death; 5 were receiving antidepressant drugs. 5-HT, 5-HIAA and 5-HT turnover did not differ significantly between the total, drug-free and antidepressant-treated suicides and controls in frontal and temporal cortex, caudate and hippocampus. 5-HIAA concentration was significantly higher in amygdala of drug-free suicides than controls, whereas 5-HT and 5-HT turnover did not differ. 5-HT concentration was significantly lower in putamen of the total and antidepressant-treated suicides and a similar reduction was also apparent in the drug-free suicides. 5-HT turnover in putamen was significantly higher in the total and drug-free suicides compared to controls. 5-HT and 5-HIAA concentrations in putamen were significantly lower in drug-free suicides who died by non-violent means than in those who died by violent means. Differences between controls and suicides could not be attributed to age, sex or postmortem delay. These results offer no support for the view that 5-HT turnover is reduced in depressed subjects who commit suicide.