Childhood adversity and cannabis use are considered independent risk factors for psychosis, but whether different patterns of cannabis use may be acting as mediator between adversity and psychotic disorders has not yet been explored. The aim of this study is to examine whether cannabis use mediates the relationship between childhood adversity and psychosis.

Data were utilised on 881 first-episode psychosis patients and 1231 controls from the European network of national schizophrenia networks studying Gene–Environment Interactions (EU-GEI) study. Detailed history of cannabis use was collected with the Cannabis Experience Questionnaire. The Childhood Experience of Care and Abuse Questionnaire was used to assess exposure to household discord, sexual, physical or emotional abuse and bullying in two periods: early (0–11 years), and late (12–17 years). A path decomposition method was used to analyse whether the association between childhood adversity and psychosis was mediated by (1) lifetime cannabis use, (2) cannabis potency and (3) frequency of use.

The association between household discord and psychosis was partially mediated by lifetime use of cannabis (indirect effect coef. 0.078, s.e. 0.022, 17%), its potency (indirect effect coef. 0.059, s.e. 0.018, 14%) and by frequency (indirect effect coef. 0.117, s.e. 0.038, 29%). Similar findings were obtained when analyses were restricted to early exposure to household discord.

Harmful patterns of cannabis use mediated the association between specific childhood adversities, like household discord, with later psychosis. Children exposed to particularly challenging environments in their household could benefit from psychosocial interventions aimed at preventing cannabis misuse.

To describe the process by which the 12 community-based primary health care (CBPHC) research teams worked together and fostered cross-jurisdictional collaboration, including collection of common indicators with the goal of using the same measures and data sources.

A pan-Canadian mechanism for common measurement of the impact of primary care innovations across Canada is lacking. The Canadian Institutes for Health Research and its partners funded 12 teams to conduct research and collaborate on development of a set of commonly collected indicators.

A working group representing the 12 teams was established. They undertook an iterative process to consider existing primary care indicators identified from the literature and by stakeholders. Indicators were agreed upon with the intention of addressing three objectives across the 12 teams: (1) describing the impact of improving access to CBPHC; (2) examining the impact of alternative models of chronic disease prevention and management in CBPHC; and (3) describing the structures and context that influence the implementation, delivery, cost, and potential for scale-up of CBPHC innovations.

Nineteen common indicators within the core dimensions of primary care were identified: access, comprehensiveness, coordination, effectiveness, and equity. We also agreed to collect data on health care costs and utilization within each team. Data sources include surveys, health administrative data, interviews, focus groups, and case studies. Collaboration across these teams sets the foundation for a unique opportunity for new knowledge generation, over and above any knowledge developed by any one team. Keys to success are each team’s willingness to engage and commitment to working across teams, funding to support this collaboration, and distributed leadership across the working group. Reaching consensus on collection of common indicators is challenging but achievable.

Rapid reviews are of increasing importance within Health Technology Assessment (HTA) due to the need for timely evidence to underpin the assessment of new technologies as well as financial constraints. There are many rapid review methods available (1) although there is little guidance as to the most suitable methods (2). A recent paper outlines issues to consider when selecting rapid review methods (3). The aim of this presentation is to present key aspects to consider when selecting rapid review methods.

We searched the evidence base for guidance on the selection of rapid review methods. We also examined three recently completed systematic reviews to identify rapid review methods used, the reasons for selection and the strengths and weaknesses of each method. Finally we identified key aspects to consider when selecting rapid review methods.

The evidence on guidance identified for the selection of rapid review methods was very limited. The analysis of the three reviews found that each review had distinctly different challenges, such as large numbers of relevant trials and heterogeneity in terms of populations, interventions, comparators and outcomes. All reviews included at least ten randomized controlled trials and numerous outcome measures. Three different approaches to the rapid review of the evidence were used in the three reviews. Key themes to consider when selecting rapid review methods were identified. These include: the size and nature of the evidence base, the characteristics of included studies and the expectations of those commissioning the review.

Rapid review methods need to be chosen to fit the needs of the review, each of which may have different challenges. Collaboration between those producing rapid reviews and commissioners is crucial when choosing methods to ensure that the needs of commissioners are met and limitations associated with the chosen methods are understood.

Multiple databases are often searched in Health Technology Assessment systematic reviews. However in rapid reviews, time and resources are limited and modifications to the search methodology may be necessary. In this retrospective study, the impact of searching fewer databases for three completed rapid reviews (i) Severe Mental Illness (SMI), (ii) Cannabis Cessation (CC), iii) Premature Ejaculation (PE) for the United Kingdom National Institute for Health Research was investigated.

The database coverage and indexing of the study references from the reviews were initially identified. The impact of fewer databases searched was then tested by (i) the number of studies that might be missed, (ii) the number of records for sifting and (iii) the overall rapid review conclusions.

A total of 178 included study references were found in the reviews (SMI n = 14 for 13 studies, CC n = 34 for 33 studies, PE n = 130 for 102 studies). Searching Medline only for SMI, Medline+Embase for CC, Medline+Embase+Cochrane Library for PE, would result in 1902 (74 percent), 466 (43 percent) and 240 (11 percent) fewer records needed to sift, respectively. There would also be a total of ten ‘would be missed’ references (SMI n = 1, CC n = 5 and PE n = 4). However, nine out of the ten references were found to have no or minimal impact on the overall findings of the reviews. The ten references were secondary reports of an included study, papers that lacked sufficient data for meta-analysis such as a conference abstract or an ongoing trial.

From the three reviews examined, limiting the search to fewer databases had no or minimal impact on the review conclusions despite the variable number of studies that would be missed and records needed to sift. More exploration during the scoping search prior to commencing the review will aid the decision on whether to limit the search to fewer databases.