title: Increased plasma concentrations of the 5-HT precursor amino acid tryptophan and other large neutral amino acids in violent criminals.
abstract: BACKGROUND
  Aggression has been suggested to be related to abnormal brain 5-HT activity. This amine is synthesized in brain from tryptophan, which is transported through the blood-brain barrier in competition with other amino acids. The relationship between tryptophan and its endogenous amino acid competitors in plasma might thus influence the availability of tryptophan in the brain and consequently brain 5-HT activity.
  
  
  METHODS
  Plasma amino acids were determined in 89 offenders who had committed various violent and non-violent crimes and in 14 healthy controls.
  
  
  RESULTS
  Both tryptophan and its competitors were higher in offenders who had committed violent crimes compared both with non-violent offenders and with controls. No difference was, however, seen in the relationship between tryptophan and its competitors.
  
  
  CONCLUSIONS
  The results support the contention that violent behaviour is related to biochemical deviations but could not explain a possible decreased brain 5-HT activity.
authors.affiliation: Department of Pharmacology, Göteborg University, Sweden.
authors.forename: T
authors.initials: T
authors.lastname: Eriksson
authors.forename: L
authors.initials: L
authors.lastname: Lidberg
mesh_terms: D000328:Adult; D000374:Aggression / Q000502:physiology; D000596:Amino Acids / Q000097:blood*; D001921:Brain / Q000503:physiopathology; D003415:Crime / Q000523:psychology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012701:Serotonin / Q000502:physiology*; D014364:Tryptophan / Q000097:blood*; D014754:Violence / Q000523:psychology*
chemical_list: D000596:Amino Acids; D012701:Serotonin; D014364:Tryptophan