Is family size related to adolescence mental hospitalization?

The aim of this study was to investigate the association between family size and psychiatric disorders of underage adolescent psychiatric inpatients. The study sample consisted of 508 adolescents (age 12–17) admitted to psychiatric impatient care between April 2001 and March 2006. Diagnostic and Statistical Manual of Mental Disorders, fourth edition-based psychiatric diagnoses and variables measuring family size were obtained from the Schedule for Affective Disorder and Schizophrenia for School-Age Children Present and Lifetime (K-SADS-PL). The family size of the general Finnish population was used as a reference population. There was a significant difference between the family size of the inpatient adolescents and the general population: 17.0% of adolescents came from large families (with 6 or more children) while the percentage in the general population was 3.3. A girl from a large family had an about 4-fold risk of psychosis other than schizophrenia. However, large family size was not associated with a risk for schizophrenia. Large family size was overrepresented among underage adolescents admitted for psychiatric hospitalization in Northern Finland.