Edinburgh Napier University

  Loneliness may be related to psychotic symptoms but a comprehensive synthesis of the literature in this area is lacking. The aim of the current study is to determine the magnitude and reliability of the loneliness-psychosis relationship in people diagnosed with schizophrenia or related disorders, taking into account study quality, and whether it is moderated by method of assessment. A search of electronic databases was conducted (PsychINFO, MEDLINE, EMBASE and Web of Science). A random effects meta-analysis was used to compute a pooled estimate of the correlation between loneliness and psychotic symptoms. Study and outcome quality were assessed using adapted versions of the Agency for Healthcare Research and Quality (AHRQ) tool and GRADE approach, respectively. Thirteen studies were included, providing data from 15,647 participants. A moderate association between psychosis and loneliness was observed (k=13, N=15,647, r=0.32, 95% CI 0.20, 0.44; I2 97.56%; moderate quality evidence). Whether loneliness was assessed by a single-item or a more comprehensive measure had no moderating effect on the estimate. Results indicate that there is a significant positive relationship between loneliness and psychosis. Further studies are needed to determine the causal status of this relationship, but this robust finding should be considered in clinical practice and treatment provision for those with psychotic disorders.