The answer is relatively straightforward: Research has established a direct and potent association between trauma and addictive behaviours. As an example, nearly two-thirds of people diagnosed with Post-Traumatic Stress Disorder (PTSD) develop issues with substance use and dependence. And more importantly, the symptoms of trauma typically arise before the substance use disorder. The evidence also suggests that the likelihood of having a substance use disorder increases with the amount of trauma people experience in their lives and that the earlier the trauma occurs, the more complex the substance use issues can become.