The rising tide of drug-induced psychosis

Summary Recreational use of psychotogenic drugs has become more common in the last 30 years with consequent increase in drug-induced psychosis; 25–50% of such psychoses progress to schizophrenia within 5 years. Most cases result from abuse of methamphetamine or cannabis. The spread of methamphetamine psychosis has occurred without any liberalisation of laws; it is highly addictive and easy to make in small “kitchen” labs. The increase in cannabis use has been facilitated by a softening of attitudes towards the drug, and in some countries, especially in North America, by legalisation for so-called “medicinal use” and then recreational use. The potency of cannabis has greatly increased, especially in countries that have legalised its use, and the worldwide legal sales of cannabis for 2025 are estimated at $ 65 billion. The consequences are being seen with many reports of increases in the incidence of cannabis-psychosis and schizophrenia. In the 1980s some physicians predicted an epidemic of obesity and diabetes due to changes in diet and life style. Sadly, their predictions were correct. We are now at the beginning of a similar epidemic of drug-induced psychosis. Public education campaigns of the type that decreased tobacco smoking are necessary to avoid psychiatric services being overwhelmed.