This paper reviews 18 surveys of mental health problems among homeless adolescents and reports on a pilot study of the same topic conducted in Amsterdam. Sampling methods and measures of mental health are discussed. The reported estimates of mental health problems vary greatly, very probably because of methodological differences. Despite the different methods used, there seems to be considerable research evidence to support a high prevalence of mental disorders among homeless adolescents. The results of the pilot study of 50 homeless adolescents in Amsterdam are consistent with the surveys reviewed. A highly structured interview was conducted at all four services sites for homeless adolescents in Amsterdam. Of the homeless adolescents interviewed, 78% had at least one lifetime DIS/DSM-III-R diagnosis, and 64% had at least one 1-month diagnosis.

Differences and similarities in homelessness in Amsterdam and New York City were examined, particularly in regard to persons most at risk for homelessness--those with mental illness and with substance abuse problems. The Netherlands is a welfare state where rents are controlled by the national government and more than half of the housing is public housing. Virtually all homeless people in Amsterdam are unemployed and receive some sort of social security benefit. Direct comparisons of the results of American and Dutch studies on homelessness are impossible, mainly because the estimates are uncertain. Because of the Dutch welfare system, Amsterdam has a smaller proportion of homeless people than New York City, although more people are homeless in Amsterdam today than 15 years ago. Neither a lack of affordable housing or sufficient income nor unemployment has been a direct cause of the increase of homelessness. As in New York City, many of the homeless in Amsterdam are mentally ill or have substance use disorders. The increase in the number of homeless people in Amsterdam consists largely of mentally ill people who would have been admitted to a mental hospital 20 years ago and of older, long-term heroin abusers who can no longer live independently. Thus institutional factors such as fragmentation of services and lack of community programs for difficult-to-serve people are a likely explanation of the growing number of homeless people in Amsterdam.