The assessment of capacity limitations in psychiatric work disability evaluations by the social functioning scale Mini-ICF-APP

Objective: Insurers frequently commission medical experts to estimate the degree of the remaining work capacity (RWC) in claimants for disability benefits. The social functioning scale Mini-ICF-APP allows for a rating of activity and participation limitations in thirteen capacity domains, considered as particularly relevant for work ability. The current study sought to evaluate the role of the Mini-ICF-APP ratings in psychiatric work disability evaluations, by examining how the capacity limitation ratings varied with the claimants' primary psychiatric diagnoses and how the ratings were related to RWC estimates.

Methods: Medical experts estimated the RWC of 946 claimants with mental disorders and rated their activity and participation limitations using the Mini-ICF-APP, with higher ratings reflecting more severe limitations. The ratings were compared between claimants with different psychiatric diagnoses by analyses of variance. The mean Mini-ICF-APP rating across all capacity domains as well as all capacity-specific ratings were entered in simple or multiple regression models to predict the RWC in an alternative job.

Results: The Mini-ICF-APP capacity limitation ratings in all domains but mobility were higher for claimants with personality and behavior disorders as compared to those with mood disorders or with neurotic, stress-related and somatoform disorders. The largest differences were observed in social capacities (e.g. group integration: F _{2, 847} = 78.300, P < 0.001). In claimants with depression, all ratings increased with the severity of the diagnosis (all Fs _{2, 203} > 16.393, all Ps < 0.001). In the overall sample, the mean Mini-ICF-APP rating showed a strong negative correlation with the estimated RWC (r = -.720, P < 0.001). Adding the capacity-specific ratings to the prediction model improved this prediction only marginally.

Discussion: The Mini-ICF-APP allows for documenting claimants' activity and participation limitations, which is likely to increase the transparency of medical experts' RWC estimates and enables them to check the plausibility of such estimates. However, our study showed that despite the strong association between RWC and Mini-ICF-APP ratings, half of the RWC variance was unrelated to the capacity limitations documented in the Mini-ICF-APP.