3. The psychology of ageing
Psychological theories of ageing encompass mental health and emotional well-being as well as changes in these states, at individual as well as interpersonal levels, associated with increasing age. ‘The psychology of ageing’ reviews different ways of studying changes in functioning: cross-sectional, longitudinal, and sequential study designs; the varying psychological theories of ageing, including the disengagement theory, activity theory, continuity theory, socioemotional selectivity theory, convoy theory, and social identity theory; and the cognitive aspects of ageing, including changes in thinking and behaviour as a result of both primary and secondary ageing. It also considers how personality and emotions are expressed in later life and the treatment of mental disorders.