Am J Psychiatry 1995; 152:850-855
Copyright © 1995 by American Psychiatric Association
Platelet serotonin-2A receptors: a potential biological marker for suicidal behavior
GN Pandey, SC Pandey, Y Dwivedi, RP Sharma, PG Janicak and JM Davis
Department of Psychiatry, University of Illinois at Chicago 60612, USA.
OBJECTIVE: Abnormalities in the serotonergic system have been implicated in
suicidal behavior. Higher numbers of serotonin-2 (5-HT2) receptors have
been reported in the post-mortem brain of suicide victims. In order to
further examine the role of 5-HT2A receptors in suicidal behavior, the
authors studied 5-HT2A receptors in platelets of suicidal and nonsuicidal
patients as well as normal comparison subjects. METHOD: 5-HT2A receptor
levels were determined by using [125I]LSD as a radioligand in platelets
obtained from hospitalized psychiatric patients (N = 131) and
nonhospitalized normal comparison subjects (N = 40) during a drug-free
baseline period. Patients were diagnosed according to DSM-III-R criteria,
and suicidal behavior was identified by using the Hamilton Depression
Rating Scale. RESULTS: The mean maximum number of binding sites (Bmax) of
platelet 5-HT2A receptors for all suicidal patients was significantly
higher than for nonsuicidal patients or normal comparison subjects. This
significant difference remained when subgroups of suicidal patients with
depression, schizophrenia, schizoaffective disorder, or bipolar illness
were compared to the other two subject groups. The higher number of
platelet 5-HT2A receptors in suicidal patients was independent of
diagnosis. While there was no significant difference in Bmax between
patients with serious suicidal ideation and those who made suicidal
attempts, both groups had significantly higher Bmax than normal comparison
subjects. CONCLUSIONS: The observed higher number of platelet 5-HT2A
receptors in suicidal patients is independent of diagnosis and appears to
be associated with both the brain and the platelets of suicidal patients.
These results thus suggest the potential usefulness of platelet 5-HT2A
receptors as a biological marker for identifying suicide-prone patients.
