The assessment of disability in patients with psychotic disorders: an application of the ICIDH-2

Objectives: To describe the application of the International Classification of Functioning and Disability (ICIDH-2) in the assessment of disability in patients with psychotic disorders. Method: The study was conducted at the inpatient unit of St Vincent's Mental Health Service, Melbourne. Twenty inpatients with psychotic disorders were concurrently assessed by two raters. An evaluation of the feasibility of the instrument was made during this process. Inter-rater agreement was determined using raw agreement percentages and weighted kappas. Results: The ICIDH-2 provides a comprehensive framework for the description and measurement of disability, including the dimensions of impairments in body structures and functions, activity limitations, participation restrictions and environmental factors. Certain codes are difficult for clinicians to rate because of the subjective manner in which they are defined. Our inter-rater reliability assessment varied across the dimensions from poor to almost perfect agreement. Conclusions: The ICIDH-2 is potentially useful in the clinical assessment of disability in patients with psychotic disorders although modifications are needed. These could include the use of anchor points defined for each dimension or code to assist the rating process and an alternative rating scale in which categories for rating are more broadly defined. Formal training may also be necessary to enable standardization of the rating process. There is also a need to augment measurements by clinicians with the assessment of the subjective experience of patients using self-rated disability and assessment of quality of life.