Issues and developments related to assessing function in serious mental illness.

Serious mental illness (SMI) results in functional disability that imposes a significant burden on individuals, caregivers, and society. Development of novel treatments is under way in an effort to improve the illness domains of cognitive impairment and negative symptoms and subsequently to improve functional outcomes. The assessment of functional outcomes in SMI faces a number of challenges, including the proliferation of assessment instruments and the differential prioritization of functional goals among stakeholder groups. Functional assessments relying on self- and informant report present a number of limitations. Identifying alternative strategies to assess functioning that are reliable, valid, and sensitive to change is necessary for use in clinical trials. Measures of functional capacity have been proposed for clinical trials investigating compounds to treat cognitive impairment in schizophrenia. Alternative approaches employing effort-based decision making or daily activity recording using instruments such as the Daily Activity Report may be more appropriate for studies focused on improving negative symptoms.