Interrelationships of long-term changes in recovery domains among patients with schizophrenia spectrum disorders: a six-year follow-up study

BACKGROUND: 

Social functioning, symptoms, cognition and well-being are all considered important recovery domains for patients with schizophrenia spectrum disorders (SSD). In the current study, we investigated to what extent longitudinal changes in one recovery domain moderated changes in another recovery domain, and which personal, clinical or social patient characteristics influence changes in recovery domains for patients with SSD.

METHODS: 

We investigated data from GROUP, a prospective, longitudinal six-year study of patients with SSD. We analyzed longitudinal changes in 15 outcomes (i.e., subdomains of symptoms, social functioning, cognition, quality of life or well-being), through a linear mixed-effects model analysis. Changes in other outcomes, patients' duration of illness (DOI), and personal, clinical, or social patient characteristics at baseline were treated as covariates in the analyses. 

RESULTS: 

We observed long-term improvement in all outcomes, except for depressive symptoms and subjective well-being. Larger improvements in positive symptoms, social functioning and executive functioning were indicated for patients with a short DOI. We found multiple, moderating effects, mainly for patients with a short DOI, between changes in cognition, social functioning, symptoms and quality of life. Limited moderating effects were indicated between these recovery domains and well-being. Baseline levels of outcomes, schizophrenia diagnosis, education level, ethnicity, living situation, employment status and marital status were all moderators for changes in most outcomes. 

CONCLUSIONS: 

Symptoms, social functioning, cognition and quality of life often concurrently improved over the course of SSD. These longitudinal changes were mostly driven by social patient characteristics, such as education level, ethnicity, living situation, employment status and marital status. CLINICAL TRIAL NUMBER: Not applicable.