“There is good evidence that taking cannabis leads to acute adverse mental effects in a high proportion of regular users. Many of these effects are dose-related, but adverse symptoms may be aggravated by constitutional factors including youthfulness, personality attributes and vulnerability to serious mental illness…
An appreciable proportion of cannabis users report short-lived adverse effects, including psychotic states following heavy consumption, and regular users are at risk of dependence…
The untoward mental effects of cannabis may be classified:
- Psychological responses such as panic, anxiety, depression or psychosis. These effects may be described as ‘toxic’ in that they generally relate to excess consumption of the drug.
- Effects of cannabis on pre-existing mental illness and cannabis as a risk-factor for mental illness.
- Dependency or withdrawal effects.”