Cannabis use is associated with increased risk of later psychotic disorder but whether it affects incidence of the disorder remains unclear. We aimed to identify patterns of cannabis use with the strongest effect on odds of psychotic disorder across Europe and explore whether differences in such patterns contribute to variations in the incidence rates of psychotic disorder. We included patients aged 18-64 years who presented to psychiatric services in 11 sites across Europe and Brazil with first-episode psychosis and recruited controls representative of the local populations. We applied adjusted logistic regression models to the data to estimate which patterns of cannabis use carried the highest odds for psychotic disorder. Using Europe-wide and national data on the expected concentration of Δ9-tetrahydrocannabinol (THC) in the different types of cannabis available across the sites, we divided the types of cannabis used by participants into two categories: low potency (THC <10%) and high potency (THC ≥10%). Assuming causality, we calculated the population attributable fractions (PAFs) for the patterns of cannabis use associated with the highest odds of psychosis and the correlation between such patterns and the incidence rates for psychotic disorder across the study sites. Between May 1, 2010, and April 1, 2015, we obtained data from 901 patients with first-episode psychosis across 11 sites and 1237 population controls from those same sites. Daily cannabis use was associated with increased odds of psychotic disorder compared with never users (adjusted odds ratio [OR] 3·2, 95% CI 2·2-4·1), increasing to nearly five-times increased odds for daily use of high-potency types of cannabis (4·8, 2·5-6·3). The PAFs calculated indicated that if high-potency cannabis were no longer available, 12·2% (95% CI 3·0-16·1) of cases of first-episode psychosis could be prevented across the 11 sites, rising to 30·3% (15·2-40·0) in London and 50·3% (27·4-66·0) in Amsterdam. The adjusted incident rates for psychotic disorder were positively correlated with the prevalence in controls across the 11 sites of use of high-potency cannabis (r = 0·7; p=0·0286) and daily use (r = 0·8; p=0·0109). Differences in frequency of daily cannabis use and in use of high-potency cannabis contributed to the striking variation in the incidence of psychotic disorder across the 11 studied sites. Given the increasing availability of high-potency cannabis, this has important implications for public health. Medical Research Council, the European Community's Seventh Framework Program grant, São Paulo Research Foundation, National Institute for Health Research (NIHR) Biomedical Research Centre (BRC) at South London and Maudsley NHS Foundation Trust and King's College London and the NIHR BRC at University College London, Wellcome Trust.

The World Health Organization Ten-Country Study,¹ the most recent multicenter international study of the incidence of psychotic disorders, was widely interpreted as demonstrating worldwide homogeneity in rates of schizophrenia and other psychotic disorders. In fact, there was a 2.5-fold variation in broadly defined nonaffective psychoses.

Psychomotor agitation is associated with different psychiatric conditions and represents an important issue in psychiatry. Current recommendations on agitation in psychiatry are not univocal. Actually, an improper assessment and management may result in unnecessary coercive or sedative treatments. A thorough and balanced review plus an expert consensus can guide assessment and treatment decisions. An expert task force iteratively developed consensus using the Delphi method. Initial survey items were based on systematic review of the literature. Subsequent surveys included new, re-worded or re-rated items. Out of 2175 papers assessing psychomotor agitation, 124 were included in the review. Each component was assigned a level of evidence. Integrating the evidence and the experience of the task force members, a consensus was reached on 22 statements on this topic. Recommendations on the assessment of agitation emphasise the importance of identifying any possible medical cause. For its management, experts agreed in considering verbal de-escalation and environmental modification techniques as first choice, considering physical restraint as a last resort strategy. Regarding pharmacological treatment, the "ideal" medication should calm without over-sedate. Generally, oral or inhaled formulations should be preferred over i.m. routes in mildly agitated patients. Intravenous treatments should be avoided.