Methodology of China's national study on the evaluation, early recognition, and treatment of psychological problems in the elderly: the China Longitudinal Aging Study (CLAS).

Cognitive and depressive disorders are common in elderly Chinese and are becoming an increasingly important public health problem, partly because of the rapid aging of the population. To help address this issue China's national government has funded a major study to establish national standards for the early identification, evaluation and treatment of common psychological disorders in the elderly. The present paper describes the overall methodology of this study. Fifteen centers in eight provinces will recruit representative samples of subjects aged 60 and over, collect a detailed history, conduct a physical and neurological examination, administer a comprehensive battery of psychological tests, and carry out a diagnostic exam using the Structured Clinical Interview for DSM-IV (SCID). These subjects will participate in follow-up evaluations one year and three years after the initial evaluation. Subsamples of subjects with mild cognitive impairment (MCI) and subclinical depression will be enrolled in randomized controlled trials of a cognitive training program (for MCI) or group cognitive behavioral therapy (for subclinical depression). The results of the study will be used to estimate the prevalence of cognitive and affective disorders in the elderly, to develop a standard screening procedure for these conditions that can be promulgated nationally, and to promote the use of specific interventions that can prevent the development of dementia in persons with MCI and the development of depressive episodes in elderly individuals with subclinical depression.