The metabolic implications of long term cannabis use in patients with psychosis

The aim of this paper is to summarise the effects of cannabis use on appetite and energy balance, and to subsequently investigate the possible implications this may have in patients with psychosis, in whom a high prevalence of cannabis use has been reported.

A narrative review based on the recent literature regarding cannabis use in the general population and patients with psychosis.

The short-term abilities of cannabis to increase appetite and body weight, through actions on the endogenous endocannabinoid system, have been well characterised throughout the literature. The long term effects of cannabis use are however unclear and only a minority of studies have been conducted in the general population with overall conflicting results. In terms of the effects of cannabis in patients with psychosis, there has only been one study to date that has investigated this and interestingly found cannabis use to be associated with increased body weight and blood glucose levels, thus providing evidence that cannabis use may be an important contributing factor to the reduced life expectancy, as is currently observed in this vulnerable patient group.

It is clear from the literature that patients with psychosis are at a high risk of metabolic and cardiovascular disease in comparison to the general population. However the contribution of cannabis use to this risk is as of yet undetermined and further long term studies are need to confirm current findings and evaluate hypothesised mechanisms.