Psychological distress is a widespread indicator of mental health and mental illness in research and clinical settings. A recurrent finding from epidemiological studies and population surveys is that women report a higher mean level and a higher prevalence of psychological distress than men. These differences may reflect, to some extent, cultural norms associated with the expression of distress in women and men. Assuming that these norms differ across age groups and that they evolve over time, one would expect gender differences in psychological distress to vary over the life-course and over time. The objective of this study was to investigate the construct validity of a psychological distress scale, the K6, across gender in different age groups and over a twelve-year period. This study is based on data from the Canadian National Population Health Survey (C-NPHS). Psychological distress was assessed with the K6, a scale developed by Kessler and his colleagues. Data were examined through multi-group confirmatory factor analyses. Increasing levels of measurement and structural invariance across gender were assessed cross-sectionally with data from cycle 1 (n = 13019) of the C-NPHS and longitudinally with cycles 1 (1994-1995), 4 (2000-2001) and 7 (2006-2007). Higher levels of measurement and structural invariance across gender were reached only after the constraint of equivalence was relaxed for various parameters of a few items of the K6. Some items had a different pattern of gender non invariance across age groups and over the course of the study. Gender differences in the expression of psychological distress may vary over the lifespan and over a 12-year period without markedly affecting the construct validity of the K6. This study confirms the cross-gender construct validity of psychological distress as assessed with the K6 despite differences in the expression of some symptoms in women and in men over the life-course and over time. Findings suggest that the higher mean level of psychological distress observed in women reflects a true difference in distress and is unlikely to be gender-biased. Gender differences in psychological distress are an important public health and clinical issue and further researches are needed to decipher the factors underlying these differences.

Population surveys and health services registers are the main source of data for the management of public health. Yet, the validity of survey data on the use of mental health services has been questioned repeatedly due to the sensitive nature of mental illness and to the risk of recall bias. The main objectives of this study were to compare data on the use of mental health services from a large scale population survey and a national health services register and to identify the factors associated with the discrepancies observed between these two sources of data.

Workplace violence can lead to serious consequences for victims, organizations, and society. Most workplace violence prevention programs aim to train staff to better recognize and safely manage at-risk situations. The Omega education and training program was developed in Canada in 1999, and has since been used to teach healthcare and mental health workers the skills needed to effectively intervene in situations of aggression. The present study was designed to assess the impact of Omega on employee psychological distress, confidence in coping, and perceived exposure to violence. This program was offered to 105 employees in a psychiatric hospital in Montreal, Canada. Eighty-nine of them accepted to participate. Questionnaires were completed before the training, after a short period of time (M = 109 days) and at follow-up (M = 441 days). Repeated-measures ANOVAs and Cohen’s d effect sizes were calculated. Results demonstrated statistically significant improvements in short-term and follow-up posttest scores of psychological distress, confidence in coping, and in levels of exposure to violence. This study is one of very few to demonstrate the positive impact of this training program. Further research is needed to understand how to improve the effectiveness of the program, especially among participants resistant to change.