Limitations in activities of daily living: towards a better understanding of subthreshold mental disorders in old age.

Based on a representative sample of elderly subjects, a description of the limitations in activities of daily living (ADL) and instrumental ADL (IADL) at subthreshold levels of dementia and depression is presented and compared against a sample of psychiatric non-cases and samples with specified levels of the respective illnesses. Additionally, it was analyzed whether these limitations are useful diagnostic markers with regard to subdiagnostic psychiatric disorders. Even at subthreshold levels of depression and dementia, elderly people suffer quite extensively from ADL and IADL limitations. However, multifactorial analyses indicate little evidence that these limitations are specific for psychiatric morbidity, be it at subdiagnostic or specified levels. By and large, ADL and IADL limitations in an elderly sample have to be considered instead as consequences of physical health-related comorbidity. Thus, issues regarding the treatment of ADL and IADL limitations at subdiagnostic as well as specified levels of psychiatric morbidity may not be solved from a psychiatric point of view alone, and a multifactorial, i.e., multiprofessional, perspective is strongly recommended.