People who struggle with substance use disorders often struggle in other areas as well. Much of the time, an additional mental disorder such as depression, anxiety or even an eating disorder accompany the problems of substance addiction. Conduct disorder also often plays a role with substance use disorder, with both disorders frequently co-occurring in families across generations.
A recent study by Jon Randolph Haber and colleagues examined the effect of paternal alcohol and drug dependence on offspring conduct disorder, looking at the gene-environment interplay in the comorbidity of the two disorders. The study used an offspring-of-twins design.
Conduct disorder is characterized by a pattern of behavior that violates social norms or violates the rights of others. It may be manifested in behaviors such as verbal or physical aggression or destructive behavior like lying, stealing or vandalism.
Because the comorbidity of substance use disorders and conduct disorder often occur across generations of families, the researchers wanted to understand the relationship between paternal patterns with the substance use disorders and offspring conduct disorder.
The researchers recruited 1,774 male twins from the Vietnam Era Twin Registry and their 1,917 offspring. They also included mothers of the offspring, totaling 1,202. The twins had a history of drug dependence, alcohol dependence, or neither. Based on the father’s and his twin’s history, risk groups were formed to reflect different levels of genetic and environmental risk. These groups were used to predict the conduct disorder of the offspring group.
The results show that after controlling for confounding variables, the rates of conduct disorder were much higher for the offspring of men who had a history of drug dependence or alcohol dependence when compared with men who had not had a substance abuse disorder.
The offspring at higher genetic risk also had higher rates of conduct disorder. There was a lower rate of conduct disorder among offspring with a lower environmental risk for those with a high risk paternal history, but it only applied to those with a paternal drug-dependence risk.
The results of the study show the high risk associated with having a paternal history of drug or alcohol dependence. The offspring of men with high rates of drug and alcohol dependence significantly raised the risk of developing conduct disorder.
The findings of the study highlight the lasting effects of choices regarding alcohol and drug use. Not only does making the decision to drink or use drugs affect an individual’s family, social and professional relationships, but their offspring can be affected for generations if the cycle is not broken.
