People who have both post-traumatic stress disorder (PTSD) and a drug-abuse problem often say they suffered trauma during their childhood. Studies have also shown that starting to drink alcohol before adolescence or during early adolescence is also linked to traumatic experiences in early childhood. Researchers from Columbia University in New York studied 1,119 children of Puerto Rican background; some were from Puerto Rico itself while others were from the Bronx. The children - who were aged between 10 and 13 at the start of the study - were monitored over the next two years to see if they started drinking. Children who reported both being exposed to trauma and five or more PTSD symptoms were significantly more likely to have started drinking. However, children who were exposed to trauma but had not developed PTSD symptoms were no more likely to start drinking than children who had not suffered any trauma at all.
Wu, Ping - Trauma, posttraumatic stress symptoms, and alcohol-use initiation in children Journal of Studies on Alcohol and Drugs May 2010, 71(3), 326-334