title: Total plasma l-tryptophan, free l-tryptophan and competing amino acid levels in a homicidal male adolescent with conduct disorder.
abstract: OBJECTIVE
  Several studies have shown abnormal findings in human serotonin metabolism, such as increased total plasma l-tryptophan and free l-tryptophan levels among habitually violent antisocial offenders. It is not clear if these increased l-tryptophan levels are associated with adult antisocial personality disorder (ASP) or history of substance abuse, or if these levels are already present in adolescent subjects with conduct disorder (CD).
  
  
  METHODS
  Total plasma and free l-tryptophan and competing amino acids (CAAs) were measured in a 15-year-old adolescent offender, who was convicted for two homicides, and in 10 healthy male controls of similar age and body mass index (BMI).
  
  
  RESULTS
  In the juvenile offender, plasma total l-tryptophan/CAA was 84% and free l-tryptophan/CAA 143% higher than average mean among controls.
  
  
  CONCLUSIONS
  From this very aggressive boy with CD, findings of free l- and total l-tryptophan/CAA values were similar to those of habitually violent adult ASP offenders. As severe CDs in adolescence tend to develop into adults with ASP, increased l-tryptophan/CAA and free l-tryptophan/CAA values may serve as early indicators for the development of habitually violent adult offenders.
authors.affiliation: Department of Psychiatry, University of Helsinki, Helsinki, Finland. matti.virkkunen@hus.fi
authors.forename: M
authors.initials: M
authors.lastname: Virkkunen
authors.forename: H
authors.initials: H
authors.lastname: Ebeling
authors.forename: I
authors.initials: I
authors.lastname: Moilanen
authors.forename: P
authors.initials: P
authors.lastname: Tani
authors.forename: S
authors.initials: S
authors.lastname: Pennanen
authors.forename: J
authors.initials: J
authors.lastname: Liesivuori
authors.forename: J
authors.initials: J
authors.lastname: Tiihonen
mesh_terms: D000293:Adolescent; D000596:Amino Acids / Q000097:blood*; D019955:Conduct Disorder / Q000097:blood* / Q000523:psychology*; D006708:Homicide / Q000523:psychology*; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D012016:Reference Values; D014364:Tryptophan / Q000097:blood*
chemical_list: D000596:Amino Acids; D014364:Tryptophan