Katrina Witt
Monash University
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Featured researches published by Katrina Witt.
PLOS ONE | 2013
Katrina Witt; Richard A. Van Dorn; Seena Fazel
Background Previous 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. Method We 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. Findings There 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. Conclusion Certain 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.
Schizophrenia Research | 2014
Katrina Witt; Keith Hawton; Seena Fazel
Background Suicide and violence often co-occur in the general population as well as in mentally ill individuals. Few studies, however, have assessed whether these suicidal behaviors are predictive of violence risk in mental illness. Aims The aim of this study is to investigate whether suicidal behaviors, including suicidal ideation, threats, and attempts, are significantly associated with increased violence risk in individuals with schizophrenia. Method Data for these analyses were obtained from the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) trial, a randomized controlled trial of antipsychotic medication in 1460 adults with schizophrenia. Univariate Cox regression analyses were used to calculate hazard ratios (HRs) for suicidal ideation, threats, and attempts. Multivariate analyses were conducted to adjust for common confounding factors, including: age, alcohol or drug misuse, major depression, antisocial personality disorder, depression, hostility, positive symptom, and poor impulse control scores. Tests of discrimination, calibration, and reclassification assessed the incremental predictive validity of suicidal behaviors for the prediction of violence risk. Results Suicidal threats and attempts were significantly associated with violence in both males and females with schizophrenia with little change following adjustment for common confounders. Only suicidal threats, however, were associated with a significant increase in incremental validity beyond age, diagnosis with a comorbid substance use disorder, and recent violent behavior. Conclusions Suicidal threats are independently associated with violence risk in both males and females with schizophrenia, and may improve violence risk prediction.
Journal of Occupational and Environmental Medicine | 2016
Allison Milner; Kathryn M. Page; Katrina Witt; Anthony D. LaMontagne
Objectives: This study examined the relationship between psychosocial working factors such as job control, job demands, job insecurity, supervisor support, and workplace bullying as risk factors for suicide ideation. Methods: We used a logistic analytic approach to assess risk factors for thoughts of suicide in a cross-sectional sample of working Australians. Potential predictors included psychosocial job stressors (described above); we also controlled for age, gender, occupational skill level, and psychological distress. Results: We found that workplace bullying or harassment was associated with 1.54 greater odds of suicide ideation (95% confidence interval 1.64 to 2.05) in the model including psychological distress. Results also suggest that higher job control and security were associated with lower odds of suicide ideation. Conclusions: These results suggest the need for organizational level intervention to address psychosocial job stressors, including bullying.
Psychiatry Research-neuroimaging | 2014
Jiansong Zhou; Katrina Witt; Yingdong Zhang; Chen Chen; Changjian Qiu; Liping Cao; Xiaoping Wang
The present investigation aims to identify the factors which differentiate violent from non-violent juvenile offenders, with a particular emphasis on the association between internalizing psychiatric morbidity (i.e. anxiety and depression), impulsivity, substance misuse, and violence. A total of 323 incarcerated male juvenile offenders from one of three Youth Detention Centers (YDCs) in China were recruited between August 2007 and November 2008. Interviews were conducted by trained psychiatrists using the Barratt Impulsivity Scale (BIS-11), the Screen for Child Anxiety Related Emotional Disorders (SCARED), and the Birleson Depression Self-Rating Scale (DSRS) to assess impulsivity, anxiety and depression, respectively. The Schedule for Affective Disorder and Schizophrenia for School-Age Children Present and Lifetime (K-SADS-PL) was also used to assess psychiatric diagnoses. Violent offenders had significantly higher BIS-11 total scores, and attention and nonplanning subscale scores (p<0.05). In the multiple logistic regression model, substance use disorders (SUD) and BIS-11 total scores independently predicted violence. Prison-based treatment services designed to reduce impulsivity and substance misuse in juvenile detention facilities should be prioritized.
British Journal of Psychiatry | 2015
Katrina Witt; Paul Lichtenstein; Seena Fazel
Background Violence risk assessment in schizophrenia relies heavily on criminal history factors. Aims To investigate which criminal history factors are most strongly associated with violent crime in schizophrenia. Method A total of 13 806 individuals (8891 men and 4915 women) with two or more hospital admissions for schizophrenia were followed up for violent convictions. Multivariate hazard ratios for 15 criminal history factors included in different risk assessment tools were calculated. The incremental predictive validity of these factors was estimated using tests of discrimination, calibration and reclassification. Results Over a mean follow-up of 12.0 years, 17.3% of men (n = 1535) and 5.7% of women (n = 281) were convicted of a violent offence. Criminal history factors most strongly associated with subsequent violence for both men and women were a previous conviction for a violent offence; for assault, illegal threats and/or intimidation; and imprisonment. However, only a previous conviction for a violent offence was associated with incremental predictive validity in both genders following adjustment for young age and comorbid substance use disorder. Conclusions Clinical and actuarial approaches to assess violence risk can be improved if included risk factors are tested using multiple measures of performance.
Australian and New Zealand Journal of Psychiatry | 2016
Jiansong Zhou; Katrina Witt; Yu-Tao Xiang; Xiao-Min Zhu; Xiaoping Wang; Seena Fazel
Objectives: The aim of this study was to undertake a systematic review on violence risk assessment instruments used for psychiatric patients in China. Methods: A systematic search was conducted from 1980 until 2014 to identify studies that used psychometric tools or structured instruments to assess aggression and violence risk. Information from primary studies was extracted, including demographic characteristics of the samples used, study design characteristics, and reliability and validity estimates. Results: A total of 30 primary studies were identified that investigated aggression or violence; 6 reported on tools assessing aggression while an additional 24 studies reported on structured instruments designed to predict violence. Although measures of reliability were typically good, estimates of predictive validity were mostly in the range of poor to moderate, with only 1 study finding good validity. These estimates were typically lower than that found in previous work for Western samples. Conclusion: There is currently little evidence to support the use of current violence risk assessment instruments in psychiatric patients in China. Developing more accurate and scalable approaches are research priorities.
Comprehensive Psychiatry | 2014
Jiansong Zhou; Katrina Witt; Chen Chen; Simei Zhang; Yingdong Zhang; Changjian Qiu; Liping Cao; Xiaoping Wang
BACKGROUND Whilst impulsivity is most commonly linked to the development of internalizing disorders, high levels of impulsivity, anxiety, and depression have been found in detained juvenile offenders. We therefore sought to determine whether impulsivity is associated with the development of self-reported anxiety or depression in a sample of detained juvenile offenders. METHODS 323 male juvenile offenders and 86 typically developing controls, aged 15-17 were assessed. The Schedule for Affective Disorder and Schizophrenia for School-Age Children Present and Lifetime (SADS-PL) was used to assess psychiatric diagnoses, the Barratt Impulsivity Scale (BIS-11) was used to measure impulsivity, and the Screen for Child Anxiety Related Emotional Disorders (SCARED) and the Birleson Depression Self-Rating Scale (DSRS) were used to assess self-reported anxiety and depression respectively. RESULTS Compared to controls, juvenile offenders had significantly higher scores on the BIS-11 total, as well as on the motor and nonplanning subscales (all p values <0.001), as well as higher DSRS (p<0.001) and SCARED (p<0.05) scores. Within the juvenile offender group, scores on the SCARED correlated positively with BIS-11 total, attention subscale, motor subscale, and total DSRS (all p values <0.01). DSRS scores correlated positively with BIS-11 total, attention subscale, nonplanning subscale, and total SCARED scores (all p values <0.01). Participants were then categorized low, middle or high impulsivity according to scores on the BIS-11. One-way ANOVAs demonstrated a significant difference between these tertiles on DSRS [F(2,320)=4.862, p<0.05] and SCARED total scores [F(2,320)=3.581, p<0.05]. Specifically, post-hoc analyses found that the high impulsivity tertile scored significant higher than the remaining tertiles on both DSRS (16.1 ± 0.3 vs. 14.0 ± 0.6, p<0.05) and SCARED (23.3 ± 0.9 vs. 18.4 ± 1.4, p<0.05) scores. Using multiple linear regression, BIS-11 attention scores, number of months served in custody, age, and BIS-11 nonplanning scores predicted higher levels of anxiety, whilst only BIS-11 attention and nonplanning scores predicted higher levels of depression. CONCLUSIONS In detained juvenile offenders, high impulsivity may be an important risk factor not only for the externalizing disorders, but also for anxiety and depression. Results of this study, therefore, suggest that specific facets of impulsivity may represent one mechanism underlying the emergence of anxiety and depression in this population.
Occupational and Environmental Medicine | 2017
Allison Milner; Katrina Witt; Anthony D. LaMontagne; Isabelle Niedhammer
Objectives Job stressors are known determinants of common mental disorders. Over the past 10 years, there has been evidence that job stressors may also be risk factors for suicidality. The current paper sought to examine this topic through the first comprehensive systematic review and meta-analysis of the literature to date. Methods We used a three-tier search strategy of seven electronic databases. Studies were included if they reported on a job stressor or job-related stress as an exposure and suicide ideation, self-harm, suicide attempt or suicide as an outcome. Two researchers independently screened articles. All extracted effect estimates were converted to log-transformed ORs. Results There were 22 studies that were included in meta-analysis. Overall, exposure to job stressors was associated with elevated risk of suicide ideation and behaviours. The OR for suicide ideation (14 studies) ranged from 1.45 (95% CI 1.01 to 2.08) for poor supervisor and colleague support to 1.91 (95% CI 1.22 to 2.99) for job insecurity. For suicide (six studies), exposure to lower supervisor and collegial support produced an OR of 1.16 (95% CI 0.98 to 1.38), while low job control resulted in an OR of 1.23 (95% CI 1.00 to 1.50). There were only two studies that examined suicide attempt, both of which suggested an adverse effect of exposure to job stressors. Conclusions This study provides some evidence that job stressors may be related to suicidal outcomes. However, as most studies in the area were cross-sectional and observational in design, there is a need for longitudinal research to assess the robustness of observed associations.
BMC Psychiatry | 2017
Katrina Witt; Matthew J. Spittal; Gregory Carter; Jane Pirkis; Sarah Hetrick; Dianne Currier; Jo Robinson; Allison Milner
BackgroundOnline and mobile telephone applications (‘apps’) have the potential to improve the scalability of effective interventions for suicidal ideation and self-harm. The aim of this review was therefore to investigate the effectiveness of digital interventions for the self-management of suicidal ideation or self-harm.MethodsSeven databases (Applied Science & Technology; CENTRAL; CRESP; Embase; Global Health; PsycARTICLES; PsycINFO; Medline) were searched to 31 March, 2017. Studies that examined the effectiveness of digital interventions for suicidal ideation and/or self-harm, or which reported outcome data for suicidal ideation and/or self-harm, within a randomised controlled trial (RCT), pseudo-RCT, or observational pre-test/post-test design were included in the review.ResultsFourteen non-overlapping studies were included, reporting data from a total of 3,356 participants. Overall, digital interventions were associated with reductions for suicidal ideation scores at post-intervention. There was no evidence of a treatment effect for self-harm or attempted suicide.ConclusionsMost studies were biased in relation to at least one aspect of study design, and particularly the domains of participant, clinical personnel, and outcome assessor blinding. Performance and detection bias therefore cannot be ruled out. Digital interventions for suicidal ideation and self-harm may be more effective than waitlist control. It is unclear whether these reductions would be clinically meaningful at present. Further evidence, particularly with regards to the potential mechanisms of action of these interventions, as well as safety, is required before these interventions could recommended.
American Journal of Industrial Medicine | 2017
Katrina Witt; Allison Milner; Amanda Allisey; Lauren J. Davenport; Anthony D. LaMontagne
BACKGROUND This brief report summarizes the international literature on the effectiveness of suicide prevention programs for protective and emergency services employees. METHODS A systematic search of 11 electronic databases was undertaken until June 30, 2015. Quantitative meta-analysis was undertaken to investigate the effectiveness of these programs on suicide rates at post-intervention. Qualitative analyses were also used to identify program components that may be associated with reductions in suicide rates. RESULTS A total of 13 studies were included. Only six reported sufficient information on suicide rates to enable inclusion in quantitative analyses, however. On average, these programs were associated with an approximate halving in suicide rates over an average follow-up period of 5.25 years (SD = 4.2; range: 1-11) (Incidence Rate Ratio 0.45, 95%CI 0.31-0.65; five studies; I2 14.8%). Few programs integrated activities at the primary prevention level. CONCLUSION A greater focus on the relatively neglected area of workplace primary prevention could further improve suicide prevention effectiveness. Am. J. Ind. Med. 60:394-407, 2017.