Abstract:
The objectives of the study were to determine the prevalence and correlates of depression in
adults of 25-45 years in the Kalutara Divisional Director of Health Services (DDHS) area
and to describe the conceptualization of depression among depressed patients and
psychiatrists. Study instruments were Composite International Diagnostic Interview (CIDI -
Core lifetime version 2.1) which assesses lifetime depression and Center for Epidemiologic
Studies Depression Scale (CES-D), which measures the depressive symptoms during the last
week. They were translated into Sinhala using rigorous qualitative methods and were
validated in the Psychiatric Clinic, General Hospital, Kalutara, against the consultant
psychiatrist's diagnosis made using ICD-10 Diagnostic Criteria for Research. Trained public
health midwives and public health nursing sisters collected data. The sample consisted of
960 adults selected by a two-stage cluster sampling method. The Sinhala versions of CIDI
and CES-D were found to be valid and reliable instruments based on validation against the
consultant psychiatrist's diagnosis. CIDI had the following validity and reliability measures:
sensitivity 92.7percent specificity 85.7 percent; positive predictive value 86.7 percent;
negative predictive value 92.3 percent; reliability between psychiatrist's diagnosis and CIDI
diagnosis (kappa) 0.786; internal consistency (Cronbach alpha reliability coefficient)
0.7936; Guttman split-half reliability 0.8281; inter-rater reliability (kappa) from 0.846 to
1.00; test-retest reliability (kappa) from 0.761 to 0.894. The overall response rate for the
prevalence survey was 97.8 percent. The adjusted prevalence of life-time depression of
depressive episode using CIDI and current depression of depressive symptoms using CES-D
were 7.8 percent (CI 6.1 percent - 9.5 percent) and 11.2 percent (CI 9.2 percent - 13.2
percent) respectively. Concurrent lifetime and current depression was seen in 3.9 percent
(CI 2.7-5.1 percent)
