This study investigates the relationship between the family type (two-parent and 4 different single-parent types, mainly divorced) during childhood up to 14 years of age and adult hospital-treated psychiatric disorders in a sample from the unselected, general population Northern Finland 1966 Birth Cohort (N = 11,017). Up to the end of 1994, a total of 387 individuals (3.5%) had a hospital-treated psychiatric disorder, with 3.1% in two-parent families and 5.4% in single-parent families (p < .001). The single-parent family was not associated with the child's schizophrenia or other psychotic disorders. The adjusted odds ratios (OR) for personality disorders were highest among individuals without a father before the age of 14 years (OR 4.8), or at birth only (OR 4.0), or with a history of parental divorce (OR 2.8). Parental divorce was also associated with alcoholism (OR 3.7) and parental death with depressive disorders (OR 3.4). In conclusion, we found an elevated risk of hospital-treated nonpsychotic disorder among individuals from a single-parent family background. It is likely that a combination of the single-parent family and psychosocial and/or genetic risk may influence the development of these disorders.