Coping psychologically and emotionally with such traumatic events is a challenge for everyone, and many people continue to feel greater stress and anxiety in their lives. Chronic stress and PTSD can trigger or exacerbate other problems such as alcohol and substance abuse. Research has shown a strong association between PTSD and alcohol consumption.

A study by the New York Academy of Medicine showed a marked increase among New York City residents in use of alcohol, cigarettes, and marijuana in the weeks following the September 11 attacks. In the five to eight weeks following the attacks, almost 29% of those interviewed increased their intake of these three substances. Almost 25% reported drinking more alcohol, 9.7% increased smoking, and 3.2% indicated an increase in marijuana use. Those who smoked more cigarettes and marijuana were dramatically more likely to experience PTSD than those who did not. Depression was also more common among those who increased cigarette smoking, alcohol consumption, and marijuana use.

(Vlahov D, Galea S, Resnick H, Ahern J, Boscarino JA, Bucuvalas M, Gold J, Kilpatrick D. Increased use of cigarettes, alcohol, and marijuana among Manhattan, New York, residents after the September 11th terrorist attacks. American Journal of Epidemiology. 2002:155(11):988-96.)