The prevalence of mental health factors and mental health service use varied widely across ethnic groups. Efforts are needed to better understand and address cultural and system-level barriers surrounding high unmet needs and to identify ethnically tailored and culturally appropriate clinical supports and practices to ensure equitable and timely mental health care.

The increasing acute care service use coupled with the reduction in outpatient visits suggest, overall, an increase in demand for mental health care that is not being met in ambulatory care settings.

Mental illness is widely perceived to be more of a public health issue now than in the past. Developed countries have reported increases of up to 40% in the use of acute care and ambulatory mental health services in the past 2 decades. [1][2][3][4][5] However, the prevalence of psychiatric disorders has remained stable over time in Canada,6,7 in the United States 5,8 and globally. [9][10][11] The stability in prevalence amid rising use of mental health services suggests that public perceptions and attitudes toward mental illness may have shifted.Major depression and psychological distress represent 2 of the most common mental health problems worldwide. Major depression, which includes symptoms such as depressed mood, diminished interests or pleasure, and feelings of worthlessness, 12 has a reported lifetime prevalence of 11.3% in Can-ada. 13 Psychological distress is more prevalent and is characterized by a combination of depressive and anxiety symptoms that do not meet the criteria for a diagnosis of major depressive disorder or anxiety-related disorder. 14 Measuring trends in these objectively measured conditions along with trends in perceived mental health -a subjective assessment of one's overall mental health status -can help to show whether attitudes toward mental health are changing. Although perceived mental health cannot directly correspond to objectively measured mental health conditions, evidence has shown increased service use among those self-reporting mental health issues, [15][16][17][18][19][20] indicating that this measure can play an important role in explaining changing patterns of mental health service use. To our knowledge, no previous study has concurrently RESEARCH MENTAL HEALTHTrends in objectively measured and perceived mental health and use of mental health services: a population-based study in Ontario, 2002Ontario, -2014