Abstract: Objective To investigate the intellectual characteristics and related factors for patients with mental retardation. Methods 118 patients with mental retardation and 118 normal subjects were assessed with Wechsler Adult Intelligence Scale-fourth edition of Chinese (WAIS-Ⅳ). Results The full intelligence quotient (FIQ), index and scores of subtests were significantly lower in the patients than in the controls (P<0.01), especially for those of working memory and processing speed index. The difference in percentage of significance between verbal comprehension and working memory was higher (P<0.05). The FIQ and some index of patients positively correlated with age, education level and their parents' education level (P<0.01). Conclusion The patients with mental retardation present an overall decline in intelligence,especially in the working memory and processing speed. The mental development is unbalanced in some patients, that the verbal comprehension is relatively better than working memory. The intelligence of patients with mental retardation may be related with their age, education level and their parents' education level.

Key words: mental retardation, intelligence, Wechsler Adult Intelligence Scale