July 5, 2016
Tobacco and cannabis are two of the world's most popular drugs, used respectively by 1 billion and 182 million people worldwide (World Health Organization; United Nations Office on Drugs and Crime). The adverse health effects of tobacco are well known. Short-term effects of cannabis are transient impairments in motor function and working memory, planning, and decision-making, while possible long-term health effects of heavy cannabis use include physical and psychological dependence, permanent reductionsin cognitive performance, cardiovascular and respiratory diseases, and some cancers (WHO).
Many users mix cannabis with tobacco, not only to save money but also because tobacco can increase the efficiency of cannabis inhalation. But such mixing can increase the risk of dependence, suggests a new study in Frontiers in Psychiatry.
"Cannabis dependence and tobacco dependence manifest in similar ways, so it is often difficult to separate these out in people who use both drugs," says lead author Chandni Hindocha, a doctoral student at the Clinical Psychopharmacology Unit of University College London. "Cannabis is less addictive than tobacco, but we show here that mixing tobacco with cannabis lowers the motivation to quit using these drugs."