To retrospectively identify differences in antisocial and delinquent behavior between siblings discordant for serious substance use disorders.

Research has suggested that people who develop serious substance use disorders have delinquent traits as children prior to using any illicit drugs.

A retrospective survey was conducted of 50 pairs of adult siblings who were discordant for serious substance use disorders. The self-report early delinquency scale (SRED) was used to retrospectively assess delinquent traits in childhood and adolescence.

The mean SRED 29 (illegal item) score in treatment seeking opiate dependent people (mean age= 33.5 years) was 19.6 (SE=0.9) compared to 4.8 (SE=0.6) in same sex, non-substance dependent siblings (p< 0.0001; paired Wilcoxon test). The mean SRED 58 (norm violation) score in treatment seeking opiate dependent people was 36.8 (SE=1.7) compared to 10.5 (SE=1.4) in same sex siblings (p< 0.0001; paired Wilcoxon test). 40% of patients were expelled from school compared to 12% of siblings (Yates-corrected Chi2 = 8.78; p = 0.003). 96% of patients reported problems with the police as adolescence compared to 48% of controls (Yates-corrected Chi2 = 26.24; p < 0.0001). Police problems in substance users pre-dated first use of illicit substances by 5.5 years.

The study used a validated instrument and objective reports to confirm significantly higher rates of delinquent behavior and social dysfunction in childhood for substance users compared to non-substance dependent siblings. The delinquent behaviors usually predated serious substance misuse.