Thomas S. Langner, the sociologist who helped lead the groundbreaking Midtown Manhattan Study in the 1960s, has died at 102. His research revealed that mental impairment was highly correlated with low socioeconomic status, challenging the prevailing belief that biological factors were the primary drivers of mental illness.

The study, which surveyed 1,660 Manhattan residents, found that only 18.5 percent could be considered psychologically well-adjusted. People with lower incomes showed more severe levels of mental impairment than their wealthier counterparts. Langner's work demonstrated that the accumulation of stressors like employment worries, social isolation, and family conflict, rather than any single factor, contributed to declining mental health.

Langner's findings helped launch the field of social psychiatry and influenced the 1963 Community Mental Health Act, which provided federal funding for neighborhood mental health clinics. Though the focus later shifted back to biological causes, his research remains a landmark in understanding how social and economic conditions shape mental health outcomes.