Increased Symptom Consolidation Preceding Transition to Psychosis: A Phenomenological Network Study

Abstract

Background: Recent network approaches suggest that transition to psychiatric disorders arise from divergent causal interactions among symptoms, whereby the emergence of one central symptom activates an interconnected set of other symptoms. Methods: Here, we used network analysis to test whether the transition to psychosis is preceded by aberrant symptom organisation. 63 at-risk mental state (ARMS) individuals without later transition to psychosis (ARMS-NT), 16 ARMS individuals with later transition to psychosis (ARMS-T), and 38 antipsychotic-free patients with first-episode psychosis (FEP group) were included. Symptoms were measured using Brief Psychiatric Rating Scale (BPRS) and graph theory was used to quantify global and local network properties. Group differences in symptom connectivity were assessed using functional data analysis and network-based statistics (NBS). Outcomes: While severity of BPRS items did not allow to differentiate ARMS-T and ARMS-NT patients, ARMS-T patients exhibited a widespread connectivity increase among symptoms relative to ARMS-NT individuals. AMRS-T and FEP patients also displayed highly segregated symptoms compared to ARMS-NT individuals. Furthermore, in both ARMS-T and FEP patients anxiety was the most binding (central) symptom. Interpretation: Our findings suggest that the risk of transition to psychosis relates to the consolidation of relationship among symptoms, but appears to be unrelated to the severity of symptoms per se. Phenomenological network approaches provide insight into novel prevention targets such as deconsolidation of symptom clustering. Funding Statement: This study was funded by CIHR Foundation Grant (375104/2017) to LP; AMOSO Opportunities fund to LP; Bucke Family Fund and Arcangelo Rea Family Foundation (London, Ontario). Declarations of Interests: LP reports personal fees from Otsuka Canada, SPMM Course Limited, UK, Canadian Psychiatric Association; book royalties from Oxford University Press; investigator-initiated educational grants from Janssen Canada, Sunovion and Otsuka Canada outside the submitted work. All other authors report no competing interests. Ethical Approval Statement: All participants provided written informed consent, and the study had research ethics committee permission.