Scientists Find a Connection Between 9/11 and Substance Abuse

First published 2007. To view the latest Heads Up content, click here.

untitled.JPGHow do traumatic events—such as the September 11, 2001 terrorist attacks—affect people in the area where the events occurred? In 2001, NIDA-funded researchers Dr. David Vlahov and his colleagues interviewed residents of New York City to find out. Dr. Vlahov explained the researchers’ purpose: “[9/11] was an event that affected everyone in a major way. We asked, how do people cope with the stress of a disaster? Do they turn to cigarettes, alcohol, or marijuana? What are the implications for public health planning and delivery?”

In 2001, five to eight weeks after 9/11, Dr. Vlahov investigated stress, depression, and substance abuse levels in people living in an area of New York City directly affected by the attacks. The results of this initial study showed that many of the 1,008 residents surveyed had developed symptoms of post-traumatic stress disorder (PTSD). PTSD is an anxiety disorder that can emerge in some people after exposure to a terrifying ordeal. Other residents experienced depression, an illness in which long-lasting feelings of sadness and hopelessness come to dominate a person’s life. There was also indication of an increased usage of cigarettes, alcohol, and marijuana after 9/11, particularly in those who had used these substances before 9/11.

The actual survey results showed that the rates of depression and PTSD were almost twice that of the national baseline. Some 9.7 percent of people had symptoms of depression, compared with a national baseline level of 4.9, while 7.5 could be diagnosed with PTSD, compared with a national baseline level of 3.6. Regarding the increase in substance use that was documented, the number of respondents who smoked cigarettes increased 9.7 percent, those who consumed alcohol increased 24.6 percent, and those who smoked marijuana increased 3.2 percent. (See the bar graphs on this page that show these statistics.) Researchers estimated that, within five to eight weeks after 9/ll, 265,000 people had increased their use of any of the substances in question, with 226,000 consuming more alcohol and 29,000 abusing more marijuana.

Six to nine months after this first study, Vlahov conducted an additional study among randomly selected adults in New York City to see if the rates of substance abuse, depression, and PTSD remained high. While rates of depression and PTSD were drastically reduced, substance abuse rates had not declined substantially. The results of both studies suggest that an increase in substance abuse after a disaster may be a cause for public health concern in the long term. “This study is one of the first to capture data on the effects of traumatic events on substance abuse patterns,” says Dr. Jacques Normand of NIDA. “This study reminds counselors and treatment providers to be alert to increased abuse of alcohol, tobacco, and marijuana in the wake of such events.”

Learn more about stress and drug abuse.




National Institute on Drug Abuse, “Trauma-Related Substance Abuse Persists After Mental Health Symptoms Abate,” NIDA Notes Bulletin Board, Vol. 20, No. 2 (August 2005). Accessed at
Williams, Jill S., “Depression, PTSD, Substance Abuse Increase in Wake of September 11 Attacks,” NIDA Notes Research Findings, Vol. 17, No. 4 (November 2002). Accessed at

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