ABSTRACT
Several human studies have investigated whether such serotonin findings might apply in forensic psychiatric cases. A relatively convenient way to index central serotonin levels is by performing lumbar puncture and measuring the cerebrospinal fluid (CSF) level of the serotonin metabolite 5-hydroxyindolacetic acid (5-HIAA, shown in Figure 2.3). An increase in the ratio of CSF concentration of homovanillic acid (HVA, a dopamine metabolite shown in Figure 2.2) to 5-HIAA has been reported to be correlated with psychopathic personality traits, particularly those related to disinhibited behaviors and a lack of emotionality/empathy.4-6
In 1976, Åsberg and colleagues published their finding of a bimodal distribution of the CSF 5-HIAA concentration in a cohort of 68 depressed patients, with 29% having a concentration below 15 ng mL-1.7 This lower concentration modal group was found to have a higher incidence of suicide attempts than the higher modal group, and the patients in the former group had used more violent means; two of the 20 patients in the lower modal group, compared with none of the 48 patients in the higher modal group, had died from suicide.8 It was suggested that the CSF 5-HIAA concentration might be a “biochemical suicide predictor.”
