Psychiatric disorders occur in a complex context of human relations in its social and psychological aspects. Family functioning is closely related to physical and psychological well-being of family members and its impairment affects the family as a whole.

To evaluate family functioning in two groups of adolescents (13–18 years): cases (with major depressive disorder) and controls (with no DSM-IV psychiatric disorders based on the Brazilian version of the Schedule for Affective Disorders and Schizophrenia for School Age Children-Present and Lifetime/K-SADS-PL).

Families of cases (N = 9) and controls (N = 9) were matched by adolescent's age, gender and education, number and age of siblings, parental marital status and occupational activity, and family income. An experienced systemic family therapist applied the Structured Family Interview to each family. Nine dimensions of family functioning were evaluated: communication, rules, roles, leadership, conflict, aggressiveness, affect, individuation and integration. Session transcripts were independently evaluated by two other systemic family therapists blind to the family case-control category.

Raters scored all interview items using a standardized coding system (overall agreement = 83.5%). Cases exhibited lower mean scores in seven family dimensions, specially affect (p = 0.0078). Differences were not found regarding rules and leadership.

Difficulty in expressing affect in parent-child relationships was the main characteristic of families with a depressive adolescent. Improvement of family functioning can contribute to minimize the negative influence of psychosocial and family factors on the reoccurrence, and severity of depressive episodes among depressed adolescents.