Objectives : Novelty seeking (NS) represents a dopaminergically modulated tendency toward frequent exploratory activity. Considering the reports showing the relationship between exploratory activity and amygdalar function and structure, and the fact that amygdala is one of the key structures that constitute the dopaminergic pathway in the brain, amygdala might be closely related to NS tendencies. Amygdalar subregional analysis method, which has the enhanced sensitivity compared to the volumteric approach would be appropriate in investigating the subtle differences of amygdalar structures among healthy individuals. The aim of the current study was to examine whether amygdalar subregional morphometric characteristics are associated with the NS tendencies in healthy adults using the amygdalar subregional analysis method. Methods : Twenty-six healthy adults (12 males, 14 females ; mean age $29.8{\pm}6.2$ years) were screened for eligibility. All subjects completed the Korean version of the Temperament and Character Inventory (TCI) and underwent high-resolution brain magnetic resonance imaging. Individuals were divided into 2 groups according to NS scores of the TCI. Results : Individuals of the high NS group had significantly larger laterobasal subregions in right amygdala, after adjustment with the brain parenchymal volumes. Sensitivity analyses for each potential confounding factor such as age, education years and Hamilton Depression Rating Scale (HDRS) scores demonstrated consistent results. Conclusions : This study suggests that NS differences are associated with the laterobasal subregion of the amygdala.

Objectives : Although there have been studies that examine sex differences of the brain structures using magnetic resonance imaging, studies that specifically investigate cerebellar structural differences between men and women are scarce. The purpose of current study was to examine sex differences in structures of the cerebellum using cerebellar template and cerebellum analysis methods. Methods : Sixteen men and twenty women were included in the study. A MATLAB based program (MathWorks, Natick, MA, USA), Statistical Parametric Mapping 5 (SPM5) using the spatially unbiased infra-tentorial atlas template (SUIT) as the cerebellum template, was used to analyze the brain imaging data. Results : There was no significant difference in age between men (mean age=28.1) and women (mean age=27.2). Men showed higher gray matter density than women in two left cerebellar areas including the clusters in the lobules IV and V (a cluster located across the lobules IV and V), and the lobule VIIIb (lobules IV and V, t=4.75, p<0.001 ; lobule VIIIb, t=3.08, p=0.004). Conclusions : The current study found differences in cerebellar gray matter density between men and women. The current study holds its significance for applying the template specifically developed for the analysis of cerebellum.

Objectives : The purpose of this study was to examine the changes in metabolic parameters and Positive and Negative Syndrome Scale (PANSS) scores of patients previously treated with atypical antipsychotic drugs other than paliperidone, after 8 weeks of treatment with paliperidone. Methods : Changes in body weight, body mass index, leptin, lipid levels, fasting glucose, and PANSS scores of patients who switched from other atypical antipsychotic drugs to paliperidone were measured after 8 weeks of treatment with paliperidone. We compared these results with those of patients who had not been treated with antipsychotic drugs for at least 2 weeks prior to treatment with paliperidone (antipsychotic drug-free patients). Results : The antipsychotic drug-free group (n = 9) did not show significant changes in metabolic parameters, but showed a significant improvement in total and subscale scores of PANSS. In the group that switched from other atypical antipsychotic drugs to paliperidone (n = 13), body weight, body mass index and fasting glucose level significantly increased, while total and subscale scores of PANSS significantly improved. Conclusions : Paliperidone treatment will benefit patients with schizophrenia who have been antipsychotic drug-free or who have had difficulty with other atypical antipsychotic drugs, with regard to their psychopathological state. However, if patients have been treated with other atypical antipsychotic drugs before switching to paliperidone, they could gain body weight or their fasting glucose level could increase over a short period because of a change in receptor number and sensitivity caused by the previously prescribed antipsychotic drugs, and hence, paliperidone should be prescribed with caution for these patients.

Objectives : The aim of this study was to examine the effects of brain-derived neurotrophic factor (BDNF) genetic polymorphism and job stress on the severity of alcohol drinking. It was hypothesized that individuals with the Met/Met BDNF genotype would be more vulnerable than those carrying the Val allele. Methods : Participants were 133 healthy Korean adults (mean age $28.2{\pm}1.1$). Job stress and the severity index of drinking were investigated through self-reported questionnaires. BDNF (rs6265) gene was genotyped. Results : There was no significant association between job stress and the severity of alcohol drinking. Although the severity of alcohol drinking was not associated with BDNF genetic polymorphism, there was a significant difference in men according to genotype and job stress. Men with homozygous BDNF Met allele were more severe in alcohol drinking when job stress was high, less severe in alcohol drinking when job stress was low than those carrying the Val allele (F = 4.47, p = 0.038). Also higher level of job stress was correlated with higher severity of alcohol drinking in men homozygous for BDNF Met allele (rs = 0.620, p = 0.005). Conclusions : These findings suggest the possibility that Met allele could have differential susceptibility, with men homozygous for BDNF Met allele being more susceptible to both more adverse and less adverse environmental influences.

Objectives : This study aims to identify temperament and characteristics of cannabis and methamphetamine abusers for elucidating psycho-biological variables related to certain substance abuse. Methods : A total of 320 patients who registered in the 'Hepatitis C cohorts study of intravenous drug users' between March 2006 and March 2010 participated in this study. Data on demographic variables were obtained and the Temperament and Character Inventory (TCI) and measures for nicotine dependence, alcohol dependence, depression and anxiety were assessed. After comparing TCI between cannabis, methamphetamine, and co-abusers, correlations between TCI and other clinical variables were examined. Results : The methamphetamine abuser group showed significantly higher scores in Novelty Seeking (NS2) and Harm Avoidance (HA3) in temperament than the cannabis abuser and co-abuser groups, whereas the cannabis abuser group had higher scores in purposefulness (SD2), congruent second nature (SD5), and self-directedness (SD) in character than the methamphetamine abuser group. In addition, temperaments and characters correlated with various psychiatric symptoms. Conclusions : We found the differences in temperament and characters among cannabis abusers, methamphetamine abusers. These findings might contribute to further understanding of mechanisms of cannabis and methamphetamine abuse.

Objectives : The purpose of this study is to investigate the relationship between the triallelic serotonin transporter gene and stressful life events to determine their effect on depression with alcohol dependence. Methods : Ninety-five hospitalized patients with alcohol dependence (73 male, 22 female) were enrolled in this study. Thirty-two (33.7%) of the total patients were diagnosed with major depressive disorder and dysthymic disorder by Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders-IV. The characteristics of stress were evaluated using the stressful life events scale, and depressive symptoms were assessed using the depression scale (Beck Depression Inventory, BDI). Alcoholism with depression (n = 32) and alcoholism without depression (n = 63) were genotyped for the triallelic serotonin transporter gene ($L_A$ : higher expressing allele, $L_G$/S : lower expressing allele). Results : There was no significant difference in the allele frequency between the depression group and the non-depression group (${\chi}^2$ = 0.345, p = 0.619). $L_G$/S alleles had more comorbid depression in the higher score of stressful life events scale [Mental-Haenszel (MH)-${\chi}^2$ = 4.477, p = 0.034]. But there was no significant difference in the comorbidity according to the scores from the stressful life event scale in the $L_A$ alleles (MH-${\chi}^2$ = 0.741, p = 0.399). In the results, alcohol-dependent individuals with $L_G$/S alleles had more comorbid depression than those with $L_A$ alleles when they had experienced severe stressful life events (MH-odds ratio = 2.699, p = 0.028). Conclusions : These results suggest that there is no direct relationship between triallelic serotonin transporter gene and depression in the alcohol dependent patients. But alcohol dependent individuals with the lower expressing alleles of the serotonin transporter gene were more susceptible to depression than those with the higher expressing alleles in response to stressful life events.