Background: To determine whether the tryptophan hydroxylase gene (ie,
the gene that codes for the rate-limiting enzyme in the metabolic path
way of serotonin) may be a susceptibility factor for suicidal behavior
. Methods: Genotypic and allelic frequencies at a polymorphic Ava II r
estriction site were revealed with the use of the complementary DNA tr
yptophan hydroxylase probe C2-38 in 62 suicide attempters. The psychia
tric characteristics of these suicide attempters were determined using
the Schedule for Affective Disorders and Schizophrenia-Lifetime versi
on with modification for the study of anxiety disorders, and these cha
racteristics were compared with those in 52 healthy controls. Results:
No association between tryptophan hydroxylase and suicidal behavior w
as detected. Conclusion: The tryptophan hydroxylase gene was not a sus
ceptibility factor for suicidal. behaviors in the group of suicide att
empters in this study.