Assessment of patient life engagement in schizophrenia using items from the Positive and Negative Syndrome Scale

Abstract

BACKGROUND: Improved patient life engagement is a meaningful treatment goal in schizophrenia that cannot be satisfactorily measured using existing tools. This research aimed to determine whether certain items from the Positive and Negative Syndrome Scale (PANSS) can assess patient life engagement in schizophrenia.

METHODS: Three approaches were used to identify PANSS items that reflect patient life engagement: (1) a panel discussion with expert psychiatrists (n = 4); (2) interviews with patients with schizophrenia (n = 20); and (3) a principal component analysis to explore clustering of items (n = 954 from three randomized controlled trials). Internal consistency was assessed by Cronbach's alpha and item-total correlations. A minimal clinically important difference (MCID) was determined by anchor- and distribution-based methods.

RESULTS: Expert psychiatrists identified 11 relevant items, and patients rated 13 items as "very relevant" to patient life engagement, most of which clustered in the principal component analysis. Considering all results, a composite set of 14 PANSS items that may be relevant to patient life engagement in schizophrenia was devised: P2, N1, N2, N3, N4, N5, N6, N7, G6, G7, G11, G13, G15, G16 (Cronbach's alpha, 0.84; item-total correlations, 0.35-0.56, indicating acceptable correlation with the underlying concept; exception: G6 [depression], 0.19). An MCID of 5 points (small/moderate improvement) or 10 points (large improvement) may be appropriate.

CONCLUSIONS: A subset of 14 PANSS items may be used to reflect patient life engagement in clinical practice/trials in schizophrenia, complementing the results of traditional psychiatric symptom scales with a patient-centered outcome that is relevant to real-world treatment goals.