Original Research Construct Validity of an Instrument to Assess Major Depression in Parents in Epidemiologic Studies

community study of children that examines the risk factors, such as parental depression, linked to childhood psychopathology and maladaptive functioning. Our goal was to test the construct validity of an instrument to assess major depression in the parents. Method: Parents of a representative sample of 2120 infants born in the province of Quebec in 1998 were selected. The major depression instrument was administered to the parents when the infants were aged 29 months. We tested the construct validity of the instrument by examining 1) sex differences in symptoms and prevalence, 2) the rank order of the prevalence of symptoms, 3) the clustering of symptoms, and 4) the association of depression with functional impairment and treatment-seeking behaviour. Results: Depression was twice as common in mothers as in fathers. Most mothers and fathers who reported ever being depressed for 2 or more weeks had also experienced at least 4 additional depression symptoms. The rank order of symptom prevalence was comparable to that found in other studies. At least 50 % of parents reported having talked to a professional and that suffering from depression had interfered with their functioning. Conclusions: The expected sex differences, the rank order of symptom prevalence, the symptom clustering, and the associations with functional impairment and treatment-seeking behaviour support the construct validity of a brief questionnaire on parental major depression. (Can J Psychiatry 2005;50:784–791) Information on funding and support and author affiliations appears at the end of the article