ABSTRACT

Cannabis is well-known appetite stimulant (Abel 1971; Mattes et al. 1994; Fride 2002b). It is possible that the enhancement of appetite is selective for snack foods (Foltin et al. 1986; Mattes, Shaw, and Engelman 1994. A role of the endocannabinoid system in the primitive invertebrate Hydra vulgaris has been demonstrated (De Petrocellis et al. 1999), thus pointing at a very widespread stimulatory role for cannabinoids in feeding. This, for most cannabis users, undesirable “side effect” has been clinically utilized for a number of years to combat a reduction in appetite and consequent weight reduction and wasting, as seen in conditions including AIDS and cancer (Mechoulam et al. 1998). However, few controlled clinical studies have been performed (Bennett and Bennett 1999). In open pilot studies, dronabinol (Δ9-THC) caused weight gain in the majority of subjects (Plasse et al. 1991). A relatively low dose of dronabinol, 2.5 mg twice daily, enhanced appetite and stabilized body weight in AIDS patients suffering from anorexia (Beal et al. 1997) for at least seven months. In another study on AIDS patients, no weight gain was reported over the course of 12 weeks of dronabinol administration (2.5 mg twice a day), whereas a dose of 750 mg/day of megestrol acetate (a synthetic progestational drug), effected significant weight gain (Timpone et al. 1999). In that study, a high dose of megestrol (with potential adverse effects including dyspnea and hypertension) and a low dose of dronabinol were used. Higher doses of dronabinol may be more effective, although side effects such as weakness, confusion, memory impairment and anxiety are a concern.