Sensitivity of cognitive tests in four cognitive domains in discriminating MDD patients from healthy controls: a meta-analysis.

BACKGROUND: We performed a meta-analysis in order to determine which neuropsychological domains and tasks would be most sensitive for discriminating between patients with major depressive disorder (MDD) and healthy controls. METHODS: Relevant articles were identified through a literature search of the PubMed and Cochrane Library databases for the period between January 1997 and May 2011. A meta-analysis was conducted using the standardized means of individual cognitive tests in each domain. The heterogeneity was assessed, and subgroup analyses according to age and medication status were performed to explore the sources of heterogeneity. RESULTS: A total of 22 trials involving 955 MDD patients and 7,664 healthy participants were selected for our meta-analysis. MDD patients showed significantly impaired results compared with healthy participants on the Digit Span and Continuous Performance Test in the attention domain; the Trail Making Test A (TMT-A) and the Digit Symbol Test in the processing speed domain; the Stroop Test, the Wisconsin Card Sorting Test, and Verbal Fluency in the executive function domain; and immediate verbal memory in the memory domain. The Finger Tapping Task, TMT-B, delayed verbal memory, and immediate and delayed visual memory failed to separate MDD patients from healthy controls. The results of subgroup analysis showed that performance of Verbal Fluency was significantly impaired in younger depressed patients (<60 years), and immediate visual memory was significantly reduced in depressed patients using antidepressants. CONCLUSIONS: Our findings have inevitable limitations arising from methodological issues inherent in the meta-analysis and we could not explain high heterogeneity between studies. Despite such limitations, current study has the strength of being the first meta-analysis which tried to specify cognitive function of depressed patients compared with healthy participants. And our findings may provide clinicians with further evidences that some cognitive tests in specific cognitive domains have sensitivity to discriminate MDD patients from healthy controls.

Neural substrates of affective face recognition in alexithymia: a functional magnetic resonance imaging study.

BACKGROUND: Alexithymia is a condition characterized by deficits in cognitive processing and the regulation of emotions. Several theories have been proposed for the underlying neurobiology, but the etiology of alexithymia remains unclear. METHODS: Using functional magnetic resonance imaging, we investigated brain activation measured on the scale of alexithymia in 38 individuals who were presented with neutral, sad, or angry affective facial stimuli. RESULTS: We found significant inverse correlations between the degree of alexithymia represented by the Korean version of the Toronto Alexithymia Scale (TAS-20K) and the intensity of the neural response to angry facial stimuli over neutral facial stimuli in the right caudate. This result was mainly due to the activations in factor 2 (difficulty describing feelings) in TAS-20K scale. CONCLUSIONS: The results suggest that functional impairments in the caudate of the fronto-striatal circuitry may play important roles in the pathophysiology of alexithymia.

Association between tryptophan hydroxylase 2 polymorphism and anger-related personality traits among young Korean women.

BACKGROUND/AIMS: It has been suggested that the serotonergic systems are associated with anger and aggressive behaviors. We investigated the association between several single nucleotide polymorphisms in the serotonergic genes and anger-related personality traits. METHODS: A total of 228 healthy female Korean women participated in this study. All subjects were assessed with the State-Trait Anger Expression Inventory (STAXI) and were genotyped for 3 polymorphisms: serotonin transporter (5-HTT) gene-linked polymorphic region (5-HTTLPR), tryptophan hydroxylase 1 (TPH1) A218C, and TPH2 G-703T. RESULTS: The Anger Expression-Out (AX-Out) subscale scores of the STAXI differed significantly between the genotypes for the TPH2 G-703T polymorphism (F = 4.825, p = 0.009). G/G homozygous subjects scored significantly higher on the AX-Out subscale than those with the G/T genotype. However, no significant differences were observed in the relationships between the STAXI subscale scores of subjects with other polymorphisms. CONCLUSIONS: This study suggests that the TPH2 G-703T polymorphism might contribute to anger-related traits, especially to the expression of anger.

Effect of bromocriptine on antipsychotic drug-induced hyperprolactinemia: eight-week randomized, single-blind, placebo-controlled, multicenter study.

AIM: The objective of the present study was to assess the efficacy and safety of bromocriptine treatment for patients with antipsychotic-drug-induced hyperprolactinemia in clinical practice. METHODS: This was an 8-week randomized, single-blind, placebo-controlled, multicenter study. Sixty female schizophrenia patients were enrolled and were randomly assigned to one of four treatment groups: bromocriptine 2.5 mg/day, 5 mg/day, 10 mg/day, and placebo. Serum levels of prolactin, estradiol (E2), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were evaluated on three occasions (baseline, and 4 and 8 weeks after commencement of the treatment paradigm). Extrapyramidal symptoms (EPS) and clinical symptoms were assessed using the Simpson-Angus scale and the Positive and Negative Syndrome Scale (PANSS), respectively. RESULTS: Of the 60 subjects who were enrolled, 48 completed the study (n = 14, 13, 11, and 10 in the bromocriptine 2.5 mg/day, 5 mg/day, and 10 mg/day, and placebo groups, respectively). Four patients in the 10-mg/day group, two in the 5-mg/day group, and one in the placebo group resumed menses during the study. The mean level of prolactin significantly decreased from baseline to week 4, and then plateaued, showing no significant change for the remaining 4 weeks of the study. No significant changes in LH, FSH, or E2 levels were observed throughout the 8-week study period, either within or between groups. CONCLUSION: Administration of bromocriptine is a safe method for treating antipsychotic-drug-induced hyperprolactinemia without exacerbating either psychotic symptoms or EPS.

Psychometric properties of the Patient Health Questionnaire-15 (PHQ-15) for measuring the somatic symptoms of psychiatric outpatients.

BACKGROUND: About 2% to 5% of all primary-care patients have a somatization disorder, and somatic symptoms are strongly associated with comorbid depression and anxiety disorders. OBJECTIVE: The authors evaluated the validity of the 15-item Somatization module of the Patient Health Questionnaire (PHQ-15) among psychiatric outpatients. METHOD: The PHQ-15 was administered to patients with somatic complaints; it was compared with the Beck Depression Inventory (BDI) and the General Health Questionnaire-12 (GHQ-12). Fifty-seven Korean subjects completed the survey. RESULTS: The PHQ-15 exhibited significant internal consistency, and test-retest reliability. Convergent validity with the BDI and GHQ-12 were positive. CONCLUSION: These results indicate that the Korean version of the PHQ-15 is appropriate for measuring the severity of somatic symptoms in a psychiatric outpatient setting.

An interaction between the norepinephrine transporter and monoamine oxidase A polymorphisms, and novelty-seeking personality traits in Korean females.

The personality traits associated with the noradrenergic system have not yet been clearly established. In the present study, we investigated the variable number of tandem repeats (VNTR) polymorphism of the norepinephrine transporter (NET) and monoamine oxidase A (MAOA), which are major components of the adrenergic system, to elucidate their relationship with personality. A total of 245 normal female Koreans (age 23.05+/-3.07 years, mean+/-SD) volunteered to take part in this study. They filled out a Korean version of the Temperament and Character Inventory (TCI) and were genotyped for the NET and MAOA-VNTR; the NET T-182C and MAOA-uVNTR polymorphisms were checked. We found significant main effect of NET genotype on novelty seeking (NS) score (F=5.43, p=0.021) and significant interaction between the NET and MAOA-uVNTR polymorphisms on NS score (F=11.06, p=0.001). However, there were no relationship between MAOA-uVNTR polymorphisms and NS score, and no association with other temperamental dimensions and these two polymorphisms. Our findings suggest that this functional polymorphism in the noradrenergic gene is associated with novelty seeking in Korean females.

Fluoxetine versus sertraline in the treatment of patients with undifferentiated somatoform disorder: a randomized, open-label, 12-week, parallel-group trial.

The present study was conducted to compare the effectiveness and tolerability of fluoxetine and sertraline in the treatment of undifferentiated somatoform disorder (USD), using the Patient Health Questionnaire (PHQ-15), which was specifically designed for assessing the severity of somatic symptoms. A randomized, 12-week, open-label trial of fluoxetine (10-60 mg/d) and sertraline (25-350 mg/d) in patients with USD was conducted. Six visits, at baseline and weeks 1, 2, 4, 8, and 12, were scheduled. Assessments for effectiveness and tolerability were conducted at each visit. The primary effectiveness measure was the mean change in PHQ-15 total score, from baseline to the end of treatment. Secondary effectiveness measures were the mean changes in total scores on the Beck Depression Inventory (BDI) and the 12-item General Health Questionnaire (GHQ-12), from baseline to the end of treatment. A total of 45 subjects were enrolled; of them, 28 were randomly assigned to receive fluoxetine and 17 to receive sertraline. The total score on the PHQ-15 from baseline to the end of treatment significantly decreased in the fluoxetine (-10.7, p<0.0001) and sertraline (-10.3, p<0.0001) treatment groups, with no between-group difference (F=0.0701, p=0.7924). Overall, both treatments were well tolerated and no serious adverse event was reported. This study suggests that both agents may have a potential role in the treatment of USD. A double-blind, placebo-controlled trial and/or head-to-head comparison study with larger samples are required to draw more definite conclusions.

No association between the brain-derived neurotrophic factor gene Val66Met polymorphism and tardive dyskinesia in schizophrenic patients.

OBJECTIVE: This study investigated whether the brain-derived neurotrophic factor (BDNF) gene Val66Met single-nucleotide polymorphism (SNP) is associated with antipsychotic-induced tardive dyskinesia (TD) in schizophrenia. METHODS: Genotyping was performed for the BDNF gene Val66Met SNP in Korean schizophrenic patients with (n=83) and without TD (n=126) who were matched for antipsychotic drug exposure and other relevant variables. RESULTS: The frequencies of genotypes (chi2=2.37, p=0.306) and alleles (chi2=0.03, p=0.867) did not differ significantly between these two groups. CONCLUSION: These findings suggest that the BDNF polymorphism does not play a major role in the susceptibility to TD in schizophrenic patients.

Possible association between the -2548A/G polymorphism of the leptin gene and olanzapine-induced weight gain.

Antipsychotic-induced weight gain has important effects on treatment compliance and long-term health. Several reports have indicated that a -2548A/G single-nucleotide polymorphism (SNP) of the leptin gene is associated with antipsychotic-induced weight gain. We hypothesized that there is a similar relationship between the -2548A/G SNP and olanzapine-induced weight gain. A total of 74 Korean schizophrenic patients were examined. Their weight was measured before starting olanzapine and after long-term treatment lasting for at least 3 months. The weight gain was significantly higher for patients with the AG genotype than for those with the AA genotype (p=0.029). Analysis of covariance also showed the difference of weight gain was still significant when adjusted for sex and treatment duration (p=0.046). This finding supports the presence of a relationship between the -2548A/G SNP of the leptin gene and weight gain in Korean schizophrenic patients receiving olanzapine treatment.

Manganese superoxide dismutase gene Ala-9Val polymorphism might be related to the severity of abnormal involuntary movements in Korean schizophrenic patients.

OBJECTIVE: This study examined whether the manganese superoxide dismutase (MnSOD) gene Ala-9Val single-nucleotide polymorphism (SNP) is associated with neuroleptic-induced tardive dyskinesia (TD) and the severity of the abnormal involuntary movements in Korean schizophrenic patients. METHOD: We investigated whether the MnSOD gene Ala-9Val SNP is associated with TD in Korean schizophrenic patients with (n=83) and without (n=126) TD who were matched for exposure to antipsychotics and other relevant variables. RESULTS: Logistic regression analysis revealed that being older (p=0.026) was a risk factor for TD, but that there was no significant association between MnSOD gene and TD. Abnormal involuntary movements were more severe in carriers of the Ala allele than in noncarriers (p=0.044). CONCLUSION: These findings do not support that the MnSOD gene Ala-9Val SNP is associated with TD in Korean schizophrenic patients. However, this polymorphism might be related to the severity of abnormal involuntary movements in this population.

Val158Met polymorphism in the catechol-O-methyltransferase (COMT) gene is not associated with tardive dyskinesia in schizophrenia.

OBJECTIVE: This study investigated whether the catechol-O-methyltransferase (COMT) gene V158M single-nucleotide polymorphism (SNP) influences susceptibility to tardive dyskinesia (TD). METHODS: We examined 209 Korean schizophrenic patients using the Abnormal Involuntary Movement Scale (AIMS), with genotyping performed for the COMT gene V158M SNP. RESULTS: The logistic regression analysis showed that old age [p = 0.032, OR = 1.40 (OR corresponds to 10-year), 95% CI = 1.03-1.90] was a risk factor for TD, but there was no significant association between the COMT genotype and TD. The heterozygotes (MV genotype) of the COMT gene polymorphism tended to develop TD less than homozygotes (MM and VV); however, the risk did not reach statistical significance (p = 0.050, OR = 1.81, 95% CI = 1.00-3.29). CONCLUSIONS: These results suggest that the V158M SNP of the COMT gene is not associated with TD in schizophrenia. However, there is a tendency that the heterozygous genotype of the COMT gene polymorphism has a protective effect against TD. Further investigations are warranted to evaluate a molecular heterosis of this polymorphism in development of TD in a large sample of subjects.

Association study between antipsychotics- induced restless legs syndrome and polymorphisms of dopamine D1, D2, D3, and D4 receptor genes in schizophrenia.

OBJECTIVE: The cause of restless legs syndrome (RLS) is not yet clear, but more promising theories involve dopaminergic deficiency and genetic causes. This study investigated whether single-nucleotide polymorphisms in the genes of dopamine receptors DRD1, DRD2, DRD3 and DRD4 are associated with antipsychotics-induced RLS in schizophrenia. METHODS: We evaluated 190 Korean schizophrenic patients using the diagnostic criteria of the International Restless Legs Syndrome Study Group and its rating scale for RLS. Genotyping was performed for the DRD1 gene -48A/G, DRD2 gene TaqI A, DRD3 gene Ser9Gly and DRD4 gene -521C/T single-nucleotide polymorphisms. The method of multifactor dimensionality reduction was used to analyze gene-gene interactions. RESULTS: We classified the schizophrenic patients into 96 with and 94 without RLS symptoms. The genotype frequencies of all polymorphisms investigated did not differ significantly between these 2 groups. MDR analysis did not show a significant effect of the 4 dopamine receptor gene variants on susceptibility to antipsychotic-induced RLS symptoms (p > 0.05). CONCLUSIONS: These genetics data suggest that the analyzed polymorphisms of the dopamine genes may not be associated with RLS symptoms in schizophrenia. Confirming the results reported here requires a larger-scale study involving patients taking specific antipsychotics.

Effects of methylphenidate and bupropion on DHEA-S and cortisol plasma levels in attention-deficit hyperactivity disorder.

We evaluated plasma levels of DHEA-S and cortisol before and after treating ADHD patients with one of two medications: methylphenidate (n = 12) or bupropion (n = 10). Boys with ADHD (combined type) were evaluated with the Korean ADHD rating scale (K-ARS) and the computerized ADHD diagnostic system (ADS). All assessments were measured at baseline and repeated after 12 weeks. There were significant clinical improvements in both treatment groups as measured by K-ARS and ADS. DHEA-S levels increased from baseline to endpoint, but cortisol levels did not change significantly. This study suggests that both methylphenidate and bupropion increase plasma levels of DHEA-S in boys with ADHD.

Venlafaxine versus mirtazapine in the treatment of undifferentiated somatoform disorder: a 12-week prospective, open-label, randomized, parallel-group trial.

OBJECTIVE: We set out to compare the efficacy and tolerability of mirtazapine versus venlafaxine in patients with undifferentiated somatoform disorder (USD) using the Patient Health Questionnaire-15 (PHQ-15). METHODS: This was a 12-week prospective, open-label, randomized, parallel-group trial. The trial consisted of six visits that included baseline and weeks 1, 2, 4, 8 and 12. The primary effectiveness measure was the mean change in PHQ-15 total score from baseline to the end of treatment. Secondary effectiveness measures included the mean changes in total scores on the Beck Depression Inventory (BDI) and the 12-item General Health Questionnaire (GHQ) from baseline to the end of treatment. Ninety-five subjects were randomized to either mirtazapine (n = 50) or venlafaxine (n = 45); 71 subjects completed the study (mirtazapine: n = 39/50 [78%]; venlafaxine: n = 32/45 [71%]). RESULTS: The mean total score on the PHQ-15 decreased by 34.7% (-8.4, p < 0.0001) from baseline to endpoint in the mirtazapine group and by 26.6% (-6.1, p < 0.0001) in the venlafaxine group. A marginally significant between-group difference was observed for the mean change in total score on the PHQ-15 from baseline to endpoint (F = 4.126, p = 0.046). The mean total scores on the GHQ-12 and BDI from baseline to endpoint decreased by -4.9 (29.4%, p < 0.0001) and -13.5 (55.9%, p < 0.0001), respectively, in the mirtazapine group, and by -4.3 (26.2%, p = 0.001) and -9.02 (46.0%, p < 0.0001), respectively, in the venlafaxine group. No between-group difference was observed for the mean changes in total scores on the secondary effectiveness measures from baseline to endpoint. Both treatments were well tolerated. CONCLUSION: Our findings suggest that both mirtazapine and venlafaxine may be effective and well tolerated in the treatment of patients with USD. Double-blind, placebo-controlled and/or head-to-head comparison studies are required to allow definite conclusions to be drawn.

Paroxetine for patients with undifferentiated somatoform disorder: A prospective, open-label, 8-week pilot study.

BACKGROUND: Forty-eight percent of somatic symptoms encountered in the primary care setting are medically unexplained. Such symptoms have been associated with negative impact on quality of life and with functional impairment. OBJECTIVE: The aim of this study was to assess the potential utility and tolerability of paroxetine for the treatment of undifferentiated somatoform disorder (USD), using the 15-item Patient Health Questionnaire (PHQ-15) to assess the severity of somatic symptoms. METHODS: A prospective, open-label, 8-week pilot study of paroxetine was conducted in outpatients with USD. Data were collected at baseline and at weeks 1, 2, 4, and 8. The primary measure was the mean change in PHQ-15 total score from baseline to the end of treatment. Secondary effectiveness measures included mean changes in total scores on the Beck Depression Inventory (BDI) and the 12-item General Health Questionnaire from baseline to end of treatment. A physical examination, electrocardiography, complete blood count, blood chemistry, urinalysis, and pregnancy test (for women of childbearing potential) were performed at baseline and the end of treatment. Vital signs were measured during each visit. Adverse events (AEs) were recorded during the study and included those determined using the Systematic Assessment for Treatment Emergent Events-General Inquiry. RESULTS: Forty-three Korean patients were screened for the study. Twenty-two patients (13 women, 9 men; mean [SD] age, 37.4 [12.4] years) were enrolled and 20 completed the study; 2 patients were lost to follow-up. The mean total score on the PHQ-15 from baseline to the end of treatment was significantly decreased (17.2 vs 4.3; P = 0.001), as was the mean total BDI score (12.8 vs. 6.3; P < 0.001). Overall, paroxetine was well-tolerated. Nausea and dry mouth were the most commonly reported treatment-emergent AEs (both, 5 [22.7%]); no serious AEs were reported. No abnormal laboratory results were observed. CONCLUSION: This open-label pilot study found that paroxetine had potential utility in the treatment of USD and was generally well-tolerated. These results suggest that adequately-powered, double-blind, placebo-controlled trials are warranted to more fully assess the efficacy and safety of paroxetine in the treatment of USD.

Association between serum testosterone levels and the severity of negative symptoms in male patients with chronic schizophrenia.

OBJECTIVES: Dysfunction of the hypothalamic-pituitary-gonadal axis may contribute to the pathophysiology of schizophrenia. Recent neuroendocrinological studies have suggested that gonadal sex hormones, including androgens and estrogen, play a significant role in the pathophysiology of schizophrenia. The purpose of this study was to determine any correlation between negative symptoms and the plasma levels of free testosterone, total testosterone, dehydroepiandrosterone sulfate, estradiol, and prolactin with consideration to depressive symptoms, extrapyramidal symptoms (EPS), and other factors including differences in age, diurnal variation of the serum hormone levels, and body fat composition. METHODS: The subjects were 35 male inpatients with chronic schizophrenia aged 20-39 years. The patients' psychopathology was assessed using the Positive and Negative Syndrome Scale (PANSS). The Calgary Depression Scale for Schizophrenia (CDSS) and the Drug-induced EPS scale (DIEPSS) were also used to exclude the effects of depression or drug-induced movement disorders. RESULTS: The PANSS negative scores had a significant inverse correlation with the serum total and free testosterone levels. The other hormone levels were not correlated with the PANSS negative scores. Moreover, a partial correlation analysis showed an inverse correlation between the PANSS negative subscores and the serum total and free testosterone levels after controlling for the DIEPSS and/or CDSS scores and age. CONCLUSIONS: This study indicates that total and free testosterone may play an important role in the severity of negative symptoms in male patients with schizophrenia.

Usefulness of long-acting injectable risperidone during 12-month maintenance therapy of bipolar disorder.

This study aimed to assess the safety, tolerability, efficacy, and compliance of a risperidone long-acting injection (RLAI) formulation for the maintenance treatment of stabilized bipolar patients. A prospective, open-label trial of RLAI was conducted for 12 months. Stable bipolar patients (n=11) were switched from their existing oral antipsychotic agents to RLAI, and injections were given every 2 weeks. The assessments were performed at baseline and at 6 and 12 months of treatment by using the Young Mania Rating Scale (YMRS), Clinical Global Impressions-Severity of Illness (CGI-S) scale, 17-item Hamilton Rating Scale for Depression (HAM-D), Brief Psychiatric Rating Scale (BPRS), and Extrapyramidal Symptom Rating Scale (ESRS). The satisfaction levels of subjects were evaluated at the end of the study period using a 10-point visual analog scale. Ten patients (90.9%) completed the trial, and no significant changes were seen in the YMRS, HAM-D, and BPRS scores throughout the study. CGI-S and ESRS scores were significantly decreased from the baseline to the post-12-month treatment score. Relapses were not reported by any of the participants. This result indicates that RLAI may be beneficial in the maintenance therapy of stable bipolar patients; however, an adequately powered, randomized, placebo-controlled trial is necessary to draw a definite conclusion about the role of RLAI in the maintenance treatment of bipolar patients.

Characteristics and clinical correlates of restless legs syndrome in schizophrenia.

OBJECTIVE: The cause of restless legs syndrome (RLS) has not yet been ascertained, but one of the most promising theories involves dopaminergic deficiency. In accordance with this theory, we assumed that the prevalence of RLS would be higher among schizophrenics treated with antipsychotics than in the normal population. The purpose of this study was to establish the prevalence, characteristics, and clinical correlates of RLS in schizophrenic patients undergoing treatment with antipsychotics. METHODS: A total of 182 hospitalized schizophrenic patients and 108 age- and sex-matched normal controls were enrolled. The presence of RLS and its severity were assessed using the International Restless Legs Syndrome Study Group (IRLSSG) diagnostic criteria and the IRLSSG rating scale, respectively. The Athens Insomnia Scale (AIS), Brief Psychiatric Rating Scale (BPRS), and Barnes Akathisia Rating Scale (BARS) were used to evaluate insomnia, global psychiatric symptoms, and akathisia, respectively, in schizophrenic patients. RESULTS: Of the 182 schizophrenic patients, 39 (21.4%) were found to have RLS and 87 (47.8%) met at least one of the RLS diagnostic criteria. The prevalence of RLS was significantly higher in the schizophrenia group than in the control group (p=0.009), as were the RLS scores (p<0.001). The BPRS (p=0.001) and the AIS (p<0.001) scores were higher in the RLS group than in the group with no RLS symptoms. CONCLUSION: We conclude that it is important to consider the diagnosis of RLS when schizophrenic patients complain of insomnia, and that RLS symptoms could be associated with more severe psychiatric symptoms and insomnia.

Association between monoamine oxidase A polymorphisms and anger-related personality traits in Korean women.

It has been suggested that polymorphisms in the monoamine oxidase A (MAO-A) gene are associated with aggressive and impulsive behaviors. In the present study, we investigated the association of the MAO-A variable number of tandem repeat polymorphism in the promoter region (MAO-A uVNTR) with anger-related personality traits. Specifically, MAO-A uVNTR polymorphisms were examined for associations with the State-Trait Anger Expression Inventory (STAXI) scores in 211 normal Korean women. All subjects were assessed using the STAXI and genotyped for MAO-A uVNTR status. The scores on the STAXI subscales differed significantly among the MAO-A uVNTR polymorphism genotypes in terms of anger expression-out (AX-Out) scores. Post hoc comparisons revealed significant differences between the 3/3 and 4/4, and between 3/4 and 4/4 polymorphisms. However, no significant difference was observed in other STAXI subscale scores among these genotypes. Subjects with the high-activity MAO-A uVNTR had significantly higher AX-Out scores than subjects with other genotypes. MAO-A uVNTR polymorphisms may contribute in part to the expression of anger. These findings support the hypothesis that this polymorphism in the MAO-A gene may be associated with anger-related personality traits in Korean women.

Characteristics of Internet use in relation to game genre in Korean adolescents.

As the number of internet users increases, a new game genre using the internet as a networking tool is emerging. Some game genres are regarded as having greater addiction potentials than others. Games and the internet are closely related. We investigated games frequently used by adolescents and classified each of them with the help of game professionals. We also examined internet use patterns to identify relationships between game genre and internet use patterns. 627 middle school and high school students (male 488, female 139) completed questionnaires concerning computer and game use patterns and Korean internet addiction scales. Game genres were divided into eight criteria (simulation, role playing game, web board, community, action, adventure, shooting, and sports). Using Korean internet addiction scales, 627 participants were divided into a normal group (474), a potential risk group (128), and a high-risk group (25). Each group showed significant differences in total internet addiction scores. We classified players into specific game users based upon the game types they most prefer. Role playing game users showed significantly higher internet addiction scores than web board and sports game users. Game and internet addictions are also connected with interpersonal relationship patterns. We suggest that users of some game genre have unique psychological addiction potentials that are different from others and that this influences both game selection and internet use.