The prevalence of common mental disorders has not declined in high-income countries despite substantial increases in service provision. A possible reason for this lack of improvement is that greater willingness to disclose mental disorders might have led to increased reporting of psychiatric symptoms, thus masking reductions in prevalence. This masking hypothesis was tested using data from two trials of interventions that increased willingness to disclose and that also measured symptoms. Both interventions involved Mental Health First Aid (MHFA) training, which is known to reduce stigma, including unwillingness to disclose a mental health problem.
A cross-lagged panel analysis was carried out on data from two large Australian randomised controlled trials of MHFA training. The first trial involved 1643 high school students in Year 10 (mean age 15.87 years), who were randomised to receive either teen MHFA training or physical first aid training as the control. The second trial involved 608 Australia public servants who were randomised to receive either eLearning MHFA, blended eLearning MHFA or eLearning physical first aid as the control. In both trials, willingness to disclose a mental disorder as described in vignettes and psychiatric symptoms (K6 scale) were measured pre-training, post-training and at 12-month follow-up.
Both trials found that MHFA training increased willingness to disclose. However, a cross-lagged panel analysis showed no effect of this change on psychiatric symptom scores.
Greater willingness to disclose did not affect psychiatric symptom scores. Because the trials increased willingness to disclose through a randomly assigned intervention, they provide a strong causal test of the masking hypothesis. It is therefore unlikely that changes in willingness to disclose are masking reductions in prevalence in the population.