A local authority estimates the prevalence of depression among adults in its area. Residents complete a self-report questionnaire, but questionnaires are delivered only to permanent home addresses. The authority compares the result with an estimate collected several decades ago using an earlier edition of the ICD.
Explain why the authority's findings may not show the true prevalence of depression or a true change over time.
144 exam-style questions on OCR GCSE Psychology 3.2 Theories/Explanations, covering 3.2.1 Clinical characteristics of schizophrenia, 3.2.2 Key statistics of schizophrenia, 3.2.3 Dopamine hypothesis of schizophrenia, 3.2.4 Brain structure and function in schizophrenia; criticisms, 3.2.5 Social drift theory of schizophrenia, 3.2.6 Schizophrenia research study: Daniel et al. (1991), 3.2.7 Clinical characteristics of clinical depression, 3.2.8 Key statistics of clinical depression, 3.2.9 Social rank theory of clinical depression, 3.2.10 ABC Model of clinical depression, and 3.2.11 Clinical Depression research study: Tandoc et al. (2015). Each one has a worked solution and a mark scheme showing where the marks go.