Drugs and violence are often observed as bedfellows; both have been associated with psychosis but the nature and timing of their relationships remains unclear. As part of the UK Prisoner Cohort Study, Keers et al prospectively followed up 967 prisoners convicted of sexual or violent offences (about a quarter of whom had a psychotic illness) in the community after release. Schizophrenia was associated with greater rates of violence, but the risk was mediated by untreated psychosis or when presenting with persecutory delusions – and no other definable psychopathology. Interestingly, drug-induced psychosis did not increase the risk of violence per se, once the substance misuse itself was accounted for. Does treatment have an impact on risk of violence in a population-based sample of patients with psychosis? Fazel et al demonstrated reductions in violent crime in patients during the time they were prescribed antipsychotics. Interestingly, the rates of violent crime were also reduced in patients with bipolar disorder who received mood stabilisers. Therefore, in addition to the effects of antipsychotics and mood stabilisers on relapse rates, their potential effects on violence and crime could be used to make decisions about management for these groups of patients. There is a clearer need for the appropriate treatment of prisoners with psychotic illnesses if their risk of violence is to be moderated. Cannabis is one of the most commonly used social drugs worldwide; it increases risk of psychosis, but there has been little to offer pharmacologically to those dependent upon this most prevalent illicit drug, and various trials of mood stabilisers, antidepressants and α2 adrenergic agonists have generally been disappointing. Allsop et al evaluated the novel cannabis extract nabiximols, containing cannabidiol – which has been shown to attenuate paranoia and euphoria – and tetrahydrocannabinol, delivered as a buccal spray. The active drug group showed statistically significant benefits in reduced withdrawal irritability, depression and cravings and remained longer in treatment. However, both placebo and drug groups showed reduced cannabis use at follow-up, with placebo being as effective as nabiximols in promoting longer-term cessation.
