Serotonergic Function and Suicidal Behavior in Personality Disordersa

Many investigators have studied serotonergic function as reflected in concentrations of the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the cerebrospinal fluid (CSF) in patients suffering from various psychiatric and somatic illnesses,"" and also in recovered depressed patient^"-'^ and healthyThese studies suggest that serotonergic function is disturbed in subgroups of psychiatric patients.The results have not always been conclusive, which is probably due to the influence of confounding factors such as age, sex, body height, food intake, and diurnal and seasonal fluctuations (for an overview, see Reference 5).Low concentrations of CSF 5-HIAA have repeatedly been associated with suicidal behavior, and especially with serious suicide attempts and completed suicide regardless of the nature of the psychiatric disorder (for an overview, see Reference 17).Low concentrations of CSF 5-HIAA have also been reported in healthy volunteers, and in depressed patients after recovery.A low CSF 5-HIAA, rather than being a sign of illness, may thus reflect personality traits associated with increased vulnerability for psychiatric illness and suicidal behavior.A couple of studies indicate that this vulnerability may be genetically determined.Sedvall et al., found an increased incidence of affective illness in families of low CSF 5-HIAA healthy volunteer^.'^Similarly, affective disorders were more common in families of depressed patients with low CSF 5-HIAA.I8 aResearch funded by the Swedish Medical Research Council (5454, 4545, 714/85).