Early life exposure to violence and substance misuse in adulthood-The first Brazilian national survey

Background: Substance misuse has been a major source of health and social problems in developing societies as it has been elsewhere. There is a growing body of evidence from developed nations linking early exposure to violence in childhood with substance misuse in adulthood. The role of depression on this association is not clear. This study estimates the association between early life exposure to violence, alcohol disorders and illegal substance use in adulthood and the role of depression on these associations using a national Brazilian sample. Methods: The first Brazilian National Alcohol Survey gathered information on early exposure to violence and use of psychoactive substances in 1880 participants aged 20 to 60. years old selected at random from the Brazilian household population. We used weighted logistic regression to calculate adjusted odds ratios for the associations between early exposure to violence and substance misuse. To assess the mediating effect of depression on these associations we used the Sobel-Goodman Mediation Test. Results: Witnessing violence during childhood or adolescence was reported by nearly 20% of the participants whilst over 8% reported having been victims of at least one form of violence. There was a statistically significant association between early exposure to violence and alcohol abuse and/or dependence and use of illegal substances in adulthood with a dose-response relationship. Depression partially explained the association between early exposure to violence with alcohol dependence (18.77% p< 0.001) and did not have a statistically significant mediating effect on the association with illegal substance use (5.83% p = 0.220). Conclusions: Adverse early life events may affect individual's susceptibility to substance misuse which can be partially mediated by depression. Prevalence of substance misuse in adulthood may be in part attributed to the prevalence of adverse childhood experience. While prevention is the ideal goal, detection and intervention with children exposed to violence must be prioritised.