Differential abnormalities in plasma 5-HIAA and platelet serotonin concentrations in violent suicide attempters - Relationships with impulsivity and depression

Brain serotonergic systems may participate in the regulation of mood, impul sivity and aggressive behavior. Because some monoaminergic mechanisms seem to be similar in the central nervous system and peripheral tissues, we test ed whether serotonergic or dopaminergic biochemical parameters in periphera l venous blood are related or not to violent suicide behavior. We simultane ously studied plasma serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA) and platelet 5-HT content in patients within 3 day s following a violent suicide attempt and in matched healthy controls. We e xamined their relationship with depression and impulsivity. Twenty seven dr ug-free suicide at tempters and controls were included. Plasma 5-HIAA and p latelet 5-HT concentrations were lower in suicide attempters than in contro ls. Fifteen patients were classified as impulsive (I), including all patien ts suffering from personality disorder and alcohol abuse, and 12 as non imp ulsive (NI), mostly melancholics. MADRS scores were similar in both I and N I suicide attempters. When controlling for age, plasma 5-HIAA was lower in I than in NI suicide attempters or controls; these findings are similar to those we observed recently with CSF 5-HIAA in I and NI violent suicide atte mpters. Contrarily, platelet 5-HT levels were lower in NI than in I patient s or controls. Plasma HVA was not associated with suicide behavior. Plasma 5-HIAA concentration was inversely associated with the degree of impulsivit y and platelet 5-HT with the intensity of depression. This study indicates that each peripheral serotonergic index is specifically related to a distin ct clinical feature and shows differential alteration according to the impu lsivity group. In I and NI drug-free violent suicide attempters an inverse figure between plasma 5-HIAA and platelet 5-HT data was observed indicating a non parallelism between these two peripheral variables. Further prospect ive studies are needed to investigate whether these peripheral serotonergic parameters may be used as helpful early predictors of violent suicide beha vior. (C) 2001 Elsevier Science Inc. All rights reserved.