Objectives: To determine risk factors associated with presence of depression in young adults (20-35 years). Methods: Case-control design in 6 health centers. Subjects: Young adult, visited in the past two years in primary health care. Cases: Diagnosis of depression <12 months. Controls: no diagnosis of depression or related treatment. Diagnosis confirmed by CIDI questionnaire. Random selection of controls. Measurements: Personal interview. Dependent variable: depressive syndrome present or absent. Independent: demographic, labor, economic, social, health, drug abuse and life events. Results: 95 cases and 93 controls. Response rate 57.7% and 45.0% respectively. Variables associated with depression: being female, being separated/divorced/widow, income <1000 €/month, difficulties at work, spending free time alone, have problems getting or maintaining relationships, sexual dissatisfaction, worse perceived health status, marijuana use, sedentary lifestyle, having suffered some form of discrimination, child abuse, a family member with serious psychological problems (last year). Conclusions: The risk factors found are similar to those of other studies with wide age range. Differentiating factors are abuse in childhood, spending time alone, problems with relationships. [ABSTRACT FROM AUTHOR]