Neural responses to various rewards and feedback in the brains of adolescent Internet addicts detected by functional magnetic resonance imaging.

AIM: This study aimed to examine differences in brain activation for various types of reward and feedback in adolescent Internet addicts (AIA) and normal adolescents (NA) using functional magnetic resonance imaging (fMRI). METHODS: AIA (n = 15) and NA (n = 15) underwent fMRI while performing easy tasks for which performance feedback (PF), social reward (SR) (such as compliments), or monetary reward (MR) was given. Using the no reward (NR) condition, three types of contrasts (PF-NR, SR-NR, and MR-NR) were analyzed. RESULTS: In NA, we observed activation in the reward-related subcortical system, self-related brain region, and other brain areas for the three contrasts, but these brain areas showed almost no activation in AIA. Instead, AIA showed significant activation in the dorsolateral prefrontal cortex for the PF-NR contrast and the negative correlation was found between the level of activation in the left superior temporal gyrus (BA 22) and the duration of Internet game use per day in AIA. CONCLUSION: These findings suggest that AIA show reduced levels of self-related brain activation and decreased reward sensitivity irrespective of the type of reward and feedback. AIA may be only sensitive to error monitoring regardless of positive feelings, such as sense of satisfaction or achievement.

Prevalence, correlates, and comorbidity of 12-Month tobacco dependence among ever-smokers in South Korea, during 1984-2001.

The rate of dependence among ever-users of a drug indicates the risk of developing dependence once an individual has been exposed to the drug. This is the first study to investigate 12-month tobacco dependence (TD) among ever-smokers in a community-based population. Analyses were based on two national studies of representative samples aged 18-64 in 1984 (n=5,025) and in 2001 (n=6,275), conducted with household visits and face-to-face interviews. The rates of 12-month TD among ever-smokers in men showed no significant difference between 51.6% in 1984 and 50.6% in 2001. On the contrary, the rates in women significantly increased from 33.3% in 1984 to 52.8% in 2001. After adjusting for the sociodemographic variables, 'male gender' was significantly associated with 12-month TD among eversmokers in 1984, but not in 2001. 'Unmarried' was significantly associated in 2001 but not in 1984. 'Alcohol dependence' was the only psychiatric disorder associated with 12-month TD in both study years. In conclusion, 12-month TD was found in about 50% of ever-smokers, and gender differences between the rates of 12-month TD which was observed in 1984 disappeared in 2001. Individuals with 12-month TD showed higher comorbidity with alcohol dependence than ever-smokers without TD.

Lifetime and 12-month prevalence of DSM-IV psychiatric disorders among Korean adults.

The objective was to estimate the prevalence and correlates of psychiatric disorders in a nationwide sample of Korean adults. Face-to-face interviews were conducted with the Korean version of Composite International Diagnostic Interview 2.1/DSM-IV (N = 6275, response rate 79.8%). The lifetime and 12-month prevalences for all types of DSM-IV disorders were 33.5% and 20.6%, respectively. Those of specific disorders were as follows: 17.2% and 7.1% for alcohol use disorder, 11.2% and 7.4% for nicotine use disorder, 5.2% and 4.2% for specific phobia, 4.3% and 1.7% for major depressive disorder, and 2.3% and 1.0% for generalized anxiety disorder. Among the sociodemographic variables, widowed status, higher income, and rural residence were the risk factors for both lifetime major depressive disorder and alcohol use disorder after controlling for gender, age, and education. The prevalence of psychiatric disorders was higher than those observed in other East-Asian countries and most European countries, but lower than that in the United States. Alcohol use disorder was particularly high in Korea.

Community study of dementia in the older Korean rural population.

OBJECTIVE: This study aims to estimate the prevalence of all dementias, including Alzheimer's disease (AD) and vascular dementia (VaD) in a population of Korean elderly and to identify possible risk factors which correlated with specific types of dementia. METHOD: A two-phase survey, based on a door-to-door survey, was conducted. Initially, the Korean version of the Psychogeriatric Assessment Scale (PAS-K) was administered to all 1037 participants aged 65 years and older. Three hundred and seventy people sampled from the case groups (n = 320) of PAS-K subscales and the non-case group (n = 50) entered the second phase for clinical evaluation. Dementia was defined using the DSM-III-R, NINCDS-ADRDA and NINDS-AIREN criteria. RESULTS: Among 1037 elderly people aged 65-94 years who completed the interview, 74 cases of dementia were detected, giving an overall age-standardized prevalence (95% CI) of 6.8% (6.1-7.5) (male 6.3%[5.3-7.4]; female 7.1%[6.1-8.0]). The prevalence (95% CI) of AD was 4.2% (3.6-4.7) (male 2.4%[2.0-2.8]; female 5.3%[4.5-6.1]), and it increased with age. The prevalence (95% CI) of VaD was 2.4% (2.0-2.8) (male 3.5%[2.7-4.3]; female 1.6%[1.2-2.1]). Smoking for longer than 30 pack-years significantly increased the risk of VaD (OR = 11.5 [2.8-44,6]). CONCLUSION: Long-term smoking, much more prevalent in men, may be closely related to higher risk of cerebrovascular disease that leads to vascular dementia.