Impact of Delusions and Hallucinations on Clinical Insight Dimensions in Schizophrenia Spectrum Disorders

Insight in psychosis has been conceptualized as a continuous, dynamic, and multidimensional phenomenon. This study aims to determine the impact of delusions and hallucinations in different dimensions of clinical insight in schizophrenia spectrum disorders.

Cross-sectional multicenter study including 516 patients (336 men) diagnosed with schizophrenia spectrum disorders. Based on dichotomized scores of Positive and Negative Syndrome Scale (PANSS) items P1 (delusions) and P3 (hallucinations), patients were assigned to four groups according to current clear presence of delusions (scores 4 or above 4 in PANSS item P1) and/or hallucinations (scores 4 or above 4 in PANNS item P3). Insight was assessed using the three main dimensions of the Scale of Unawareness of Mental Disorder (SUMD).

Around 40% of patients showed unawareness of illness; 30% unawareness of the need for treatment; and 45% unawareness of the social consequences of the disorder. Patients with current clear presence of delusions had higher overall lack of awareness, regardless of current clear presence of hallucinations. Similarly, the clear presence of delusions showed a greater predictive value on insight than the presence of hallucinations, although the implication of both in the prediction was modest.

Our results confirm that lack of insight is highly prevalent in schizophrenia spectrum disorders, particularly when patients experience delusions. This study adds insight-related data to the growing symptom-based research, where specific types of psychotic experiences such as hallucinations and delusions could form different psychopathological patterns, linking the phenomenology of delusions to a lack of clinical insight.