Shared psychotic disorder in children and young people: a systematic review.

This study aimed at searching the literature and reassessing the concept of shared psychotic disorder (SPD) in young people under 18 taking into account genetic vulnerability, social circumstances and family situation to have a better understanding of this condition. Published case reports from 1980 through to March 2017, which included children and adolescents meeting DSM-III/IV/IV-TR or ICD 10 criteria of SPD, were identified. Sociodemographic and clinical variables were collected and analysed; a post hoc analysis comparing inductors and induced was also conducted. Four hundred and eight articles were assessed for eligibility of which 27 were included in the qualitative and quantitative synthesis. Thirty families were described. Forty-eight children were identified including 6 inductors and 42 induced. Although delusional beliefs were presented in all subjects, hallucinations were only reported in 50% of the inductors and 27% of the inductees. Social isolation was the most common social context (83.3% of the inductors; 76.2% of the induced) and 18 out of 45 children (data missing for n = 3) were initially separated from adults involved although the outcome of the symptoms was not different from those who were not separated. Children who were inductors were more likely to meet criteria of major psychotic illness in the future. Most of the induced children involved in a case of shared psychosis were first-degree relatives of the inductor. Shared psychotic disorder probably occurs in premorbid predisposed individuals where genetic and environmental factors play an important role in the development of the psychotic episode.