The only properly design ed , low bias and highly powered study found a weight increasing effect  of dronabinol in AN , while the other , using Δ9-THC at a high dose , found no effect and where the dose may have counteracted the weight gaining effects due to adverse events .
Anorexia nervosa ( AN ) is a psychiatric disorder with a high mortality and unknown etiology , and effective treatment is lacking .
For decades , cannabis has been known to cause physical effects on the human body , including increasing appetite , which may be beneficial in the treatment of AN .
To systematic ally review the literature for evidence of an effect of cannabinoids on ( 1 ) weight gain , and ( 2 ) other outcomes , in AN .
A double-blind trial of delta 9-tetrahydrocannabinol in primary anorexia nervosa.
Δ9-Tetrahydrocannabinol ( Δ9-THC ) , the most prominent psychoactive cannabinoid in Cannabis sativa L. ( marijuana ) , has been reported to have properties of appetite stimulation , promotion of weight gain , and antiemetic efficacy in selected patient population s. In this 4-week , double-blind , crossover study , 11 female patients with primary anorexia nervosa ( PAN ) were evaluated on Δ9-THC and on an active placebo , diazepam . All patients participated in a st and ardized behavior modification treatment program . The following data were obtained : ( 1 ) daily weight , ( 2 ) daily caloric intake , and ( 3 ) weekly psychiatric assessment s. The two groups were comparable on all measures at baseline except for two items on the behavioral rating scales . The only significant differences found between the changes over time on Δ9-THC versus diazepam were more pathology on Δ9-THC for somatization , interpersonal sensitivity , and sleep disturbance . Three patients experienced severe dysphoric reactions consisting of paranoid ideation and feelings of loss of control during Δ9-THC administration . One week after the study ended , each subject was given the highest dose level of Δ8-THC achieved in the study , and periodic blood sample s were obtained coincident with self-rated “ subjective high ” assessment s and pulse measurements . Quantitative analyses of these sample s indicated peak times of 1 to 5 hours postdose for Δ9- THC and for its primary active metabolite , 11-hydroxy-THC , which generally coincided with peak times for “ subjective high ” and pulse rate . The results of this clinical investigation suggest that Δ9-THC is not efficacious , in short-term administration , in the treatment of primary anorexia nervosa and is associated with significant psychic disturbance in some PAN patients
The only properly design ed , low bias and highly powered study found a weight increasing effect  of dronabinol in AN , while the other , using Δ9-THC at a high dose , found no effect and where the dose may have counteracted the weight gaining effects due to adverse events .
Anorexia nervosa ( AN ) is a psychiatric disorder with a high mortality and unknown etiology , and effective treatment is lacking .
For decades , cannabis has been known to cause physical effects on the human body , including increasing appetite , which may be beneficial in the treatment of AN .
To systematic ally review the literature for evidence of an effect of cannabinoids on ( 1 ) weight gain , and ( 2 ) other outcomes , in AN .