From the Editor—The WHO World Mental Health Survey: Its Strengths and Weaknesses

“Most people with mental illness are not treated” is the take-home message from the most recent report about the World Health Organization (WHO) World Mental Health Survey Initiative ([Wang et al., 2007]). WHO began its ambitious project, involving coordinated surveys across the globe about mental and substance disorders, in 1998. Although data collection remains incomplete in 11 of the 28 selected countries, Wang and colleagues have analyzed the data from the first 17 (Belgium, China, Colombia, France, Germany, Israel, Italy, Japan, Lebanon, Mexico, Netherlands, New Zealand, Nigeria, South Africa, Spain, Ukraine, and United States).

Certainly a strength of the study is the inclusion of both developed and developing countries. Another strength is the face-to-face interview methodology, through which 84,850 adults were surveyed. The study has several other laudable characteristics. Stratified multistage clustered area probability sampling was used, with just a few exceptions (e.g., countries, such as Belgium, with population registries). The average response rate across countries (71%) was excellent. DSM-IV criteria ([American Psychiatric Association, 1994]) were used to establish diagnoses of anxiety, mood, and substance disorders. To stimulate participant recall and accurate reporting about treatment, data collectors showed interviewees a booklet depicting diverse caregivers (mental health professionals, family doctors, religious counselors, traditional healers) and asked them about number of visits during the previous year.

The multiple strengths of the study contribute to a reader's confidence in the researchers' conclusions: (1) there is a huge worldwide problem with regard to delivery of mental health services to consumers; (2) even in developed countries, the number of consumers receiving services is shockingly low (e.g., 18% in the United States); (3) most of those who do receive treatment do not receive adequate treatment ([Wang et al., 2007]).

However, I want to make a few comments about weaknesses of the study that must be taken into account. A major weakness is that schizophrenia was not included, because the researchers did not believe that this disorder could be adequately assessed by the laypeople used to collect study data. Another concern is the reliability and validity of the diagnoses made by the lay interviewers. Some clinicians may even question the appropriateness of DSM-IV diagnoses for such diverse cultures. Underestimation of many disorders is likely, because of interviewee reluctance to acknowledge stigmatized conditions such as alcoholism. Even admitting to problems with “nerves” or depression takes courage in many cultures. Another weakness is the low statistical power in some of the analyses about treatment, because there were too few treated respondents. Moreover, there are no data to corroborate self-reports about treatment. To the researchers' credit, they have acknowledged most of these weaknesses.

This is an important report, and I hope that it generates considerable attention from researchers, politicians, and policymakers. I encourage you to read it carefully.