RESUMEN
OBJECTIVES: This study was designed to assess the present conditions of the mental retardation in a rural area by identifying the prevalence, socioeconomic characteristics and combined diseases of the subjects with mental retardation. METHODS: For this survey, four regions of a rural area with total population of 17,235 persons were chosen. The surveys were divided into 2 steps. After Key Informant Research(KIR) at first survey, one psychiatric specialist, two psychiatric residents and five clinical psychologists interviewed the high risk group who had been selected in KIR. By this two-step process, final diagnosis and degree of severity were confirmed. Diagnostic criteria of Mental Retardation by DSM-IV(Diagnostic and Statistical Manual of Mental Disorders-IV), K-WAIS, Social Maturation Scale were used as diagnositc tools. RESULTS: Prevalence of Mental Retardation in survey areas was 0.42%. The prevalences in male and female were 0.37% and 0.47%, respectively, which were of no significant statistical difference. The relative ratio of each degree of mental retardation-mild, moderate, severe and profound mental retardation-was 33:47:18:3 respectively. The prevalence of moderate mental retardation was higher than that of any other degrees. By age groups, the prevalence in twenties and thirties was 0.69%, which was the highest of all age groups. The prevalence in forties and over was 0.35%, which was the lower than that of twenties and thirties(x2-18.64, p=0.00002). CONCLUSIONS: Prevalence of mental retardation in survey areas was 0.42%, which was higher than any other previous studies in Korea. The prevalence of mild mental retardation was relatively lower than that of other previous studies, which means that the key informants may not have detected the subjects with mild mental retardations who were relatively socially adaptive in rural areas, because they might have focused on the ability of social adaptation as an important feature in detecting the mental retardations. The prevalence of moderate mental retardation was 0.20%, higher than any other groups, which resulted from low rate of failure in the detection of the moderate mental retardations because of their severe deficits in social adaptation and from the higher prevalence than severe and profound mental retardation in reality. The prevalence of severe and profound mental retardation was low rate because they used to be short-lived due to combined medical illnesses and congenital anomalies. The persons with mental reatardation were in low socioeconomic status and had poor supporting systems.