@article{ref1,
title="Free L-tryptophan plasma levels in antisocial violent offenders",
journal="Psychopharmacology",
year="2001",
author="Tiihonen, Jari and Virkkunen, Matti and Räsänen, P. and Pennanen, S. and Sainio, E. L. and Callaway, J. and Halonen, P. and Liesivuori, J.",
volume="157",
number="4",
pages="395-400",
abstract="RATIONALE: Several studies have shown that impulsive violent behavior is associated with reduced serotonin metabolism in the brain, but no data exist on possible alterations of the serotonin precursor (free L-tryptophan) levels among violent offenders. OBJECTIVES: To study free L-tryptophan and kynurenine plasma levels among antisocial violent offenders. METHODS: Free L-tryptophan and competing amino acid (CAA) plasma levels were measured among 19 male impulsive antisocial violent offenders and 19 age-matched healthy male controls. RESULTS: Mean free L-tryptophan/(CAA) plasma levels were 160% (95% CI 116%-204%) higher among offenders than controls (P=0.000). Seventeen of the 19 offenders (89.5%) had values of more than 2 SD above the mean value of controls. The levels of kynurenine, the major metabolite of tryptophan, were slightly increased in offenders. CONCLUSION: Free plasma L-tryptophan/CAA levels were markedly increased among antisocial violent offenders indicating a disturbed tryptophan metabolism.<p /><p>Language: en</p>",
language="en",
issn="0033-3158",
doi="10.1007/s002130100842",
url="http://dx.doi.org/10.1007/s002130100842"
}