Actigraphy studies and clinical and biobehavioural correlates in schizophrenia: a systematic review.

Actigraphy is a non-invasive method of monitoring circadian rhythms and motor activity. We systematically reviewed extant evidence until September 2018 pertaining to actigraphy use in schizophrenia, its clinical/biological correlates and posit future research directions. Within 38 included studies involving 2700 subjects, patients with schizophrenia generally have lower motor activity levels, poorer sleep quality and efficiency, increased sleep fragmentation and duration compared with healthy controls. Lowered motor activity and longer sleep duration in patients were associated with greater severity of negative symptoms. Less structured motor activity and decreased sleep quality were associated with greater severity of positive symptoms, worse cognitive functioning involving attention and processing speed, illness chronicity, higher antipsychotic dose, and poorer quality of life. Correlations of actigraphic measures with biological factors are sparse with inconclusive results. Future studies with larger sample sets may adopt a multimodal, longitudinal approach which examines both motor and sleep activity, triangulates clinical, actigraphic and biological measures to clarify their inter-relationships and inform risk prediction of illness onset, course, and treatment response over time.