We aimed to describe aggression according to the subscales formed in the Life History of Aggression (LHA) in relation to life-time psychiatric diagnoses.

178 adults referred for psychiatric evaluations of childhood-onset neuropsychiatric disorders (outpatients) and 92 perpetrators of violent crimes referred to pre-trial forensic psychiatric investigations had comprehensive, instrument-based, psychiatric assessments, including the LHA scales. Total and subscale LHA scores were compared to the categorical and dimensional diagnoses of childhood and adult DSM-IV axis I and II mental disorders, general intelligence, GAF, and personality traits according to Cloninger's biopsychosocial model.

The two groups had similar LHA scores (despite higher scores on the Antisocial scale in the offender group). Higher total LHA scores were independently associated with the hyperactivity facet of attention-deficit/hyperactivity disorder (AD/HD), childhood conduct disorder, substance-related disorders, and low scores on the Cooperativeness character dimension according to the Temperament and Character Inventory. IQ and GAF-scores were negatively correlated with the LHA subscale Self-directed aggression. Autistic traits were inversely correlated with aggression among outpatients, while the opposite pattern was noted in the forensic group.

In these study groups, aggression was predicted by childhood behaviour aberrations, adult substance-related problems, and character immaturity rather than by symptoms associated with the major mental disorders. AD/HD in combined or hyperactive, but not inattentive, forms, was associated with high scores on aggressive behaviours.