Clinical validity of the 12-item WHODAS-2.0 in a naturalistic sample of outpatients with psychotic disorders

Abstract

Background The World Health Organization Disability Assessment Schedule 2.0 (WHODAS-2.0) is a self-administered instrument to assess functional impairment. It is used in the general population as well as different patient groups. However, its application to patients with psychotic disorders may be hampered by disease-specific difficulties of self-estimation. This study aimed to examine the psychometric properties of the short (12-item) WHODAS-2.0 in a naturalistic sample of outpatients attending a psychosis clinic in Gothenburg, Sweden. Methods Annual data from two outpatient clinics registered 2016–2019 were analyzed retrospectively. The assessment of the short WHODAS-2.0 was based on the first questionnaire completed by 881 patients. Confirmatory factor analysis evaluated previously validated models. Item convergent and discriminant validity as well as internal reliability were computed. Construct validity was assessed by comparing mean differences in accord with previous research regarding patients’ characteristics associated with functioning such as advanced age, diagnosed comorbidities, antipsychotic treatment status, and symptom severity measured with PANSS-8 remission items. Results A heterogeneous sample was obtained in terms of age (range: 20–92), various living situations, and different geographic areas of birth. Most patients (75%) had been diagnosed with psychotic disorders more than 10 years ago and the majority (89%) were on antipsychotic medication. We confirmed an adjusted two-level factor model with a single second-order disability factor and six first-order factors representing the six IFC dimensions. The WHODAS-2.0 sum score measuring general disability showed good reliability (Cronbach's alpha = 0.89). Construct validity was confirmed as older patients, patients with comorbidities, and patients in assisted living had higher WHODAS-2.0 scores. Patients with no or mild psychotic symptoms had significantly lower WHODAS-2.0 sum scores than patients with more severe symptoms. Conclusions The findings further validate the 12-item WHODAS-2.0 in a naturalistic sample of outpatients with psychotic disorders. This study corroborates the clinical significance of the short, 12-item WHODAS-2.0 by demonstrating consistent associations between patients’ age, medical comorbidities, living situation, antipsychotic treatment status, and psychotic symptom severity.

Elevated pulse pressure and its associations with demographic and clinical parameters in a clinically representative sample of outpatients with psychotic disorders

“…11 Of particular interest for this population and the current study, the previous validation study showed that patients who were rated low on psychotic symptom severity generally also self-assessed as having lower functional impairments. 11 This indicates that the instrument accounts for psychotic symptomology.…”

“…At a few outpatient units, we also had information about patients' functioning, assessed using the 12 item World Health Organization Disability Assessment Schedule 2.0 (WHODAS-2.0), a self-administered questionnaire. 11 This is a general assessment instrument that can be used in both patient and general population settings and has been cross-culturally validated both in patients with mental disorders and in those with somatic disorders. 12 The questionnaire contains two items corresponding to each domain of functioning (cognition, mobility, household, self-care, social and society), and the domains are directly linked to disability concepts according to the International Classification of Functioning, Disability and Health.…”

“…12 The Swedish version has been psychometrically validated in the patient population. 11 Specifically, the Swedish instrument was validated against patients’ age, clinically diagnosed comorbidities, living conditions, antipsychotic treatment status and psychotic symptom severity. 11 Of particular interest for this population and the current study, the previous validation study showed that patients who were rated low on psychotic symptom severity generally also self-assessed as having lower functional impairments.…”

Investigating the Role of Insight, Decision-Making and Mentalizing in Functional Outcome in Schizophrenia: A Cross-Sectional Study

“…Of note, a recent study from our group showed the WHODAS 2.0 to adequately measure disability aspects in both severe and common mental disorders [ 43 ]. Moreover, in an independent sample of outpatients with psychotic disorders the WHODAS 2.0 total score showed good reliability (Cronbach’s α = 0.89) [ 44 ].…”

“…The Spanish version [ 46 ] of the Positive and Negative Syndrome Scale (PANSS) [ 44 ] was used to rate severity of five symptomatic dimensions, namely positive, negative, disorganization, mania and depression, based on a previous consensus of PANSS factor analysis studies [ 47 ].…”