The Cannabinoid CB1 receptors were found to decrease by 20% in the brains of smokers. This may be an unhealthy trend since these receptors are associated by memory and stress coping mechanisms.
The study, carried out by the National Institute of Health, Maryland, USA, consisted of 46 participants, 18 of whom were frequent smokers. A drug that blocks CB1 receptors, called rimonabant, has been tested in clinical trials for smoking cessation. Although the drug seemed to help people quit smoking, it caused problematic psychiatric side effects.