Development and Validation of a Culturally Adapted Screening Tool for Common Mental Disorders in Primary Healthcare Settings in South East Nigeria

Screening for common mental disorders in Nigerian primary healthcare settings is constrained by the absence of validated, culturally adapted instruments that accurately capture local symptom expressions and idioms of distress beyond Western diagnostic categories. This study develops and validates a culturally adapted screening tool for common mental disorders including depression, anxiety, and somatic distress syndromes in primary healthcare settings in South East Nigeria, drawing on Igbo cultural illness representations. A mixed-methods instrument development design is applied across three sequential phases: Phase 1 involves ethnographic qualitative data collection through 60 in-depth interviews and 12 focused group discussions with community members and traditional healers in Anambra, Enugu, and Abia States to document local idioms of distress and explanatory models. Phase 2 applies expert consensus methods using a 15-member Delphi panel of mental health professionals, linguists, and community health workers to develop initial instrument items. Phase 3 conducts a psychometric validation study with 840 primary healthcare attendees using the criterion standard of the Structured Clinical Interview for DSM-5 administered by trained psychiatrists, evaluating sensitivity, specificity, receiver operating characteristic curve performance, factor structure through confirmatory factor analysis, and test-retest reliability. The Cultural Formulation Interview framework and Medical Anthropology Theory of Explanatory Models provide the conceptual foundations. The original contribution is a validated, Igbo-language-anchored screening tool deployable by non-specialist primary healthcare workers. Findings directly address the mental health screening gap in South East Nigeria. Keywords: mental health screening tool, cultural adaptation, validation, primary healthcare, South East Nigeria.