Pt. Mehlman et al., CORRELATION OF CSF 5-HIAA CONCENTRATION WITH SOCIALITY AND THE TIMINGOF EMIGRATION IN FREE-RANGING PRIMATES, The American journal of psychiatry, 152(6), 1995, pp. 907-913
Objective: The purpose of this study was to examine the relationship b
etween behavior and serotonin in nonhuman primates. Method: During a r
outine capture and medical examination, 26 adolescent male rhesus maca
ques (Macaca mulatta) were selected as subjects from a free-ranging po
pulation of 4,500 rhesus monkeys inhabiting a 475-acre sea island. Blo
od samples (N=23) and CSF samples (N=22) were obtained, and each subje
ct was fitted with a radio transmitter collar for rapid location. The
subjects were released into their social groups, and quantitative beha
vioral observations were made over a 3-month period. Results: CSF 5-hy
droxyindoleacetic acid (5-HIAA) concentration was positively correlate
d with three measures of sociality: 1) total time spent grooming other
s, 2) total time spent in close proximity to other group members, and
3) mean number of neighbors within a 5-m radius. In addition, CSF 5-HI
AA concentration was positively correlated with age at emigration from
the natal group (in months). Conclusions: In adolescent male rhesus m
acaques living in naturalistic settings, CSF 5-HIAA concentration is p
ositively correlated with affiliative sociality. Rhesus males with low
CSF 5-HIAA concentrations exhibit less social competence and emigrate
from their social groups at a younger age than do males with higher c
oncentrations of CSF 5-HIAA.