Abstract
BackgroundPrevious reviews on risk and protective factors for violence in psychosis have produced contrasting findings. There is therefore a need to clarify the direction and strength of association of risk and protective factors for violent outcomes in individuals with psychosis.MethodWe conducted a systematic review and meta-analysis using 6 electronic databases (CINAHL, EBSCO, EMBASE, Global Health, PsycINFO, PUBMED) and Google Scholar. Studies were identified that reported factors associated with violence in adults diagnosed, using DSM or ICD criteria, with schizophrenia and other psychoses. We considered non-English language studies and dissertations. Risk and protective factors were meta-analysed if reported in three or more primary studies. Meta-regression examined sources of heterogeneity. A novel meta-epidemiological approach was used to group similar risk factors into one of 10 domains. Sub-group analyses were then used to investigate whether risk domains differed for studies reporting severe violence (rather than aggression or hostility) and studies based in inpatient (rather than outpatient) settings.FindingsThere were 110 eligible studies reporting on 45,533 individuals, 8,439 (18.5%) of whom were violent. A total of 39,995 (87.8%) were diagnosed with schizophrenia, 209 (0.4%) were diagnosed with bipolar disorder, and 5,329 (11.8%) were diagnosed with other psychoses. Dynamic (or modifiable) risk factors included hostile behaviour, recent drug misuse, non-adherence with psychological therapies (p values<0.001), higher poor impulse control scores, recent substance misuse, recent alcohol misuse (p values<0.01), and non-adherence with medication (p value <0.05). We also examined a number of static factors, the strongest of which were criminal history factors. When restricting outcomes to severe violence, these associations did not change materially. In studies investigating inpatient violence, associations differed in strength but not direction.ConclusionCertain dynamic risk factors are strongly associated with increased violence risk in individuals with psychosis and their role in risk assessment and management warrants further examination.
Highlights
At least twenty studies have reported a positive association between schizophrenia and violence [1]
One narrative review emphasises the contribution of positive symptoms and comorbid substance misuse [8], whilst another emphasises the contribution of socio-demographic factors, theory of mind, and personality disorders in addition to positive symptoms and comorbid substance misuse [9]
Search Strategy We searched for studies indexed in six databases from their start dates: CINAHL (1 January 1982–31 December 2011), EBSCO (1 January 1980–31 December 2011), EMBASE (1 January 1980–31 December 2011), Global Health (1 January 1973–31 December 2011), PsycINFO (1 January1960–31 December 2011), PUBMED (1 January 1960–31 December 2011), as well as Google Scholar (1 January 2004–2011) using keywords that were inclusive for psychosis and violence
Summary
At least twenty studies have reported a positive association between schizophrenia and violence [1]. Less is known about risk and protective factors and the mechanisms mediating this relationship. Notable individual studies have reported contrasting findings over the role of different factors such as threat/control override symptoms [2,3], substance misuse [4,5] and positive symptoms [6,7]. Certain socio-demographic factors, were not associated with severe violence in a recent systematic review which found that a previous criminal history, a longer duration of untreated psychosis, and psychotic symptoms to be potentially important [10]. Previous reviews on risk and protective factors for violence in psychosis have produced contrasting findings. There is a need to clarify the direction and strength of association of risk and protective factors for violent outcomes in individuals with psychosis
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