Global statistics on addictive behaviours: 2014 status report.

Background And Aims: Addictive behaviours are among the greatest scourges on humankind. It is important to estimate the extent of the problem globally and in different geographical regions. Such estimates are available, but there is a need to collate and evaluate these to arrive at the best available synthetic figures.

Systematic review of the Hawthorne effect: new concepts are needed to study research participation effects.

Objectives: This study aims to (1) elucidate whether the Hawthorne effect exists, (2) explore under what conditions, and (3) estimate the size of any such effect.

Study Design And Setting: This systematic review summarizes and evaluates the strength of available evidence on the Hawthorne effect. An inclusive definition of any form of research artifact on behavior using this label, and without cointerventions, was adopted.

The effects of demand characteristics on research participant behaviours in non-laboratory settings: a systematic review.

Background: The concept of demand characteristics, which involves research participants being aware of what the researcher is investigating, is well known and widely used within psychology, particularly in laboratory-based studies. Studies of this phenomenon may make a useful contribution to broader consideration of the effects of taking part in research on participant behaviour. This systematic review seeks to summarise data from studies of the effects of demand characteristics on participant behaviours in non-laboratory settings.

Can research assessments themselves cause bias in behaviour change trials? A systematic review of evidence from solomon 4-group studies.

Background: The possible effects of research assessments on participant behaviour have attracted research interest, especially in studies with behavioural interventions and/or outcomes. Assessments may introduce bias in randomised controlled trials by altering receptivity to intervention in experimental groups and differentially impacting on the behaviour of control groups. In a Solomon 4-group design, participants are randomly allocated to one of four arms: (1) assessed experimental group; (2) unassessed experimental group (3) assessed control group; or (4) unassessed control group.

Factors associated with the prescribing of buprenorphine or methadone for treatment of opiate dependence.

The study investigates patient preferences and beliefs and treatment program factors related to the decision to prescribe either buprenorphine or methadone to opiate-dependent patients. The sample (N = 192) was recruited from 10 addiction treatment services in London. Data were collected by means of a single structured interview conducted with patients commencing a treatment episode at the participating agencies.

Cannabis use in adolescents: the impact of risk and protective factors and social functioning.

The study uses a school-based sample to test the social and familial risk and protective factors relating to cannabis use. Based on a self-completion survey of 2078 14-16-year-olds (mean age of 15 years) attending seven standard state-run secondary schools in south London, an assessment was made of rates and risk factors for cannabis use. Twenty-four per cent of the total sample had ever used cannabis, with 15% having done so in the month prior to assessment.

Reductions in criminal convictions after addiction treatment: 5-year follow-up.

Changes in criminal convictions were investigated among 1075 clients admitted to 54 drug misuse treatment services across England as part of the National Treatment Outcome Research Study (NTORS). Convictions data during the year prior to treatment, and at 1 year, 2 years, and 5 years after treatment intake were collected from the Home Office Offenders' Index, a national database of all convictions in adult and youth courts. Clinical data were collected by face-to-face interviews at intake to treatment, and at follow-up 1 year, 2 years, and 4-5 years after admission to treatment.

Causal association between cannabis and psychosis: examination of the evidence.

Background: Controversy remains as to whether cannabis acts as a causal risk factor for schizophrenia or other functional psychotic illnesses.

Aims: To examine critically the evidence that cannabis causes psychosis using established criteria of causality.

Method: We identified five studies that included a well-defined sample drawn from population-based registers or cohorts and used prospective measures of cannabis use and adult psychosis.

Cannabis use and the GP: brief motivational intervention increases clinical enquiry by GPs in a pilot study.

This preliminary test of a brief intervention designed to stimulate GP incorporation of cannabis enquiry was followed up after 2-3 months. Intervention comprised face-to-face discussion based on principles of motivational interviewing, with informational adjunct. Substantially more positive attitudes and greater clinical activity were observed following receipt of intervention.