Anticipatory pleasure for future experiences in schizophrenia spectrum disorders and major depression: a systematic review and meta-analysis

OBJECTIVES: Deficits in anticipating pleasure may be an important dimension of anhedonia and functioning in psychiatric disorders, particularly schizophrenia and depression; however, inconsistent findings have limited the conclusions that can be drawn. We conducted the first systemic review and meta-analysis of the extant literature for research comparing psychiatric groups to healthy control groups on anticipatory pleasure. METHODS: Academic Search Complete, Science Direct, and CINAHL databases were systematically searched up to 9 June 2018 for relevant peer-reviewed articles, book chapters, and dissertations. Reference lists were also hand searched. A total of 36 studies were included in the review. RESULTS: A moderate-sized deficit was observed in schizophrenia spectrum disorders (k = 32, 1,851 patients and 1,449 controls, g = -0.42 [95% CI = -0.53 to -0.31], p < .001), and a large deficit in major depression (k = 415 patients and 506 controls, g = -0.87 [95% CI = -1.23 to -0.51], p < .001), with this effect being significantly larger for depression (p < .05). Meta-regression showed that heterogeneity was partially explained in schizophrenia spectrum by longer duration of illness and lower cognitive functioning predicting larger deficits. In depression, some evidence was found that ruling out a history of psychiatric illness in controls may be related to larger effects. There was evidence for small study bias inflating estimates in schizophrenia spectrum disorders. CONCLUSIONS: Deficits in anticipatory pleasure are manifest in these disorders, and significantly more so in major depression. These findings indicate a possible therapeutic target to link cognitive, affective, and behavioural factors that precipitate and maintain disorder. PRACTITIONER POINTS: Anticipatory pleasure is impaired in schizophrenia spectrum and major depression. A particular focus on enhancing anticipatory pleasure may improve motivation for rewarding behaviour and psychosocial functioning. The review contained only a small number of studies for major depression. Given the heterogeneity in effects, there are likely to be more moderators of anticipatory pleasure that require examination.