Standard quality-of-life measures miss important aspects of life for people with schizophrenia and cannabis use | Research

The takeaway

In 103 patients with schizophrenia and cannabis abuse, the generic EQ-5D quality measure only moderately correlated with psychiatric-specific quality measures, missing important domains like relationships and finances.

Read this if you work in mental health research or policy and want to understand measurement challenges for quality of life.

Only moderate correlation (0.358) between generic and psychiatric quality measures

What the researchers found

Researchers tested whether the EQ-5D (a widely used generic health measure recommended for economic evaluations) adequately captured quality of life in patients with schizophrenia and cannabis abuse.

The EQ-5D showed only moderate correlation with the Manchester Short Assessment of Quality of Life (MANSA), a psychiatric-specific measure (rho = 0.358). Three of the five EQ-5D dimensions (Mobility, Self-Care, and Pain/Discomfort) were not sensitive in this population.

Only the "Usual Activities" and "Anxiety/Depression" dimensions showed moderate correlation with MANSA. Both measures correlated moderately with clinical scales (PANSS, GAF, WHO-DAS).

The authors recommended using EQ-5D alongside psychiatric-specific quality of life measures, as mental health interventions often target domains (relationships, finances, employment, housing) that EQ-5D does not capture.

Why it matters

Health economic evaluations using only generic measures could undervalue mental health interventions, particularly those addressing social functioning, relationships, and community integration in patients with dual diagnoses.

The numbers in context

103 patients with schizophrenia and cannabis abuse. EQ-5D vs MANSA correlation: rho = 0.358. Mobility, Self-Care, and Pain/Discomfort dimensions were insensitive. Both measures correlated moderately with PANSS, GAF, and WHO-DAS.

How the study worked

Cross-sectional analysis of 103 patients with schizophrenia and cannabis abuse from a randomized controlled trial. Correlation analysis between EQ-5D and MANSA using Spearman's coefficient, with additional correlations to PANSS, GAF, and WHO-DAS.

What this study cannot tell us

Relatively small sample (103 patients). Specific to schizophrenia with cannabis comorbidity. Correlation analysis cannot establish which measure better captures true quality of life changes.

How to read the evidence

Psychometric validation study with relevant clinical sample but relatively small size.

When this study was published

Published in 2011. Debate about appropriate quality-of-life measures in mental health continues.

The bigger picture

This methodological study highlighted a broader concern about how health economic evaluations assess value in mental health care, where treatment goals often extend beyond symptom reduction.

Questions still open

Should health economic guidelines recommend condition-specific quality measures alongside EQ-5D for mental health evaluations? How should economic evaluations capture improvements in relationships and social integration?

Common questions

Why does this matter for patients?

If standard health measures miss what matters to people with schizophrenia (relationships, housing, employment), treatments that improve these areas may be undervalued by health economists, potentially affecting funding and access.

What did the EQ-5D miss?

The EQ-5D focuses on mobility, self-care, usual activities, pain, and anxiety/depression. It missed quality-of-life domains important to this population: relationship quality, financial situation, employment, and accommodation.

Read the original research

Does the EQ-5D measure quality of life in schizophrenia?

The journal of mental health policy and economics, 14(4), 187-96

View on PubMed ↗

Citation

Halling Hastrup, Lene; Nordentoft, Merete; Hjorthøj, Carsten; Gyrd-Hansen, Dorte. (2011). Does the EQ-5D measure quality of life in schizophrenia?. The journal of mental health policy and economics, 14(4), 187-96.