Latest Research Shows Marijuana Use May Be A Gateway To Relapse

August 5, 2005

New York, NY—August 5, 2005— Results of a study released in this month’s American Journal of Psychiatry suggest that using cannabis or marijuana after treatment for cocaine or alcohol dependence is a significant predictor of relapse to previous drug/alcohol use. The study, which was carried out by researchers at the New York State Psychiatric Institute at Columbia University Medical Center, is believed to be the first such study to address the effects of cannabis use on post-discharge outcome of inpatients treated for alcohol, cocaine, and/or heroin.

While marijuana has long been considered a gateway drug, its use implicated in the subsequent graduation to the abuse of more addictive drugs like cocaine, this study now suggests marijuana may be a gateway drug to relapse.

Dr. Efrat Aharonovich, the lead investigator, and colleagues interviewed 250 adults who had received treatment for substance abuse in an inpatient setting. At the beginning of the study, 75% of the participants met the criteria for alcohol dependence, 58% met the criteria for cocaine dependence and 20% met the criteria for heroin dependence. Fifteen percent of the participants were marijuana dependent. (Dependency suggests an obsessive preoccupation in addition to chemical activity in the brain.)

Follow up interviews were conducted at six, 12 and 18 months following the initial meeting. The authors were particularly interested in determining (1) participants’ use of substances after discharge, (2) the number of participants who remained in remission (determined to be at least 26 weeks without substance use) and (3) the number of participants who relapsed, that is used marijuana one or more weeks after remission.

“We found that not only was marijuana use in those who relapsed five times greater than those who did not, but low remission rates in participants were associated with high rates of marijuana use,” said Dr. Aharonovich, a psychologist and research scientist. The findings related to heroin were far less significant, with marijuana showing no effect on relapse to the drug. “I believe our study indicates that marijuana use is not quite as harmless as one would like to think,” Dr. Aharanovich added.

While the authors concur that more studies need to be done, these findings are important in their potential implementation in the care of recovering substance abusers. In addition, Dr. Aharonovich and her colleagues point to the increased potency of marijuana and its increased abuse and dependence as even greater incentive for mental health providers to consider its role in treatment outcome.


Columbia University Medical Center provides international leadership in basic, pre-clinical and clinical research, medical education, and health care. The medical center trains future leaders in health care and includes the dedicated work of many physicians, scientists, nurses, dentists, and other health professionals at the College of Physicians & Surgeons, the School of Dental & Oral Surgery, the School of Nursing, the Mailman School of Public Health, the biomedical departments of the Graduate School of Arts and Sciences, and allied research centers and institutions. With a strong history of some of the most important advances and discoveries in health care, its researchers are leading the development of novel therapies and advances to address a wide range of health conditions.

Founded in 1896, the New York State Psychiatric Institute (PI) continues to contribute importantly to knowledge about understanding and treating psychiatric disorder and is ranked among the best psychiatric research facilities in the world today. Noted for its research on depression and suicide, schizophrenia, anxiety and child psychiatric disorders, PI is also at the forefront of research dedicated to unraveling the brain’s mysteries. Its scientists constitute the core of the Department of Psychiatry at Columbia University. In 2000, Dr. Eric Kandel was awarded the Nobel Prize in Physiology or Medicine for research in his labs at PI on the cellular basis of memory.


Efrat Aharonovich, Mailman School, Nobel Prize, PI