Doo Byung Park

Association of aggressive behavior in Korean male schizophrenic patients with polymorphisms in the serotonin transporter promoter and catecholamine-O-methyltransferase genes

The incidence of aggressive behavior in patients with schizophrenia is higher than in the general population. Among particular gene polymorphisms posited to be involved in psychiatric disorders, the catecholamine-O-methyltransferase (COMT) and serotonin transporter (5-HTTPR) genes have been the focus of recent research on aggression. In this study, we hypothesized that both the COMT and the 5-HTTPR genotypes may be dependent on and related to aggression in Korean patients with schizophrenia. The subjects were 168 unrelated male schizophrenic patients diagnosed according to DSM-IV. Among two psychiatric hospital staff and medical university students, 158 unrelated male subjects with no lifetime history of psychiatric disorders were recruited to establish the COMT and 5-HTTPR genotype distribution in the general population. All episodes of aggression from the last discharge to readmission were rated. The Total Overt Aggression Scale (OAS) score (sum of the scores of all episodes of aggression), highest OAS score (highest individual episode score, 0-16), OAS category, and OAS category score (mean score within each category) were recorded. There were statistically significant effects of COMT genotype on the mean OAS 4 (physical aggression against other people) score and the highest OAS score. The most predictive was the OAS 4 score. There was a statistically significant effect of 5-HTTPR genotype on mean total score. Thus, the COMT gene is associated with the severity of aggression and with physical aggression against other people, whereas the 5-HTTPR gene is associated with the summary score of all episodes of aggression.

The Relationships between Online Game Player Biogenetic Traits, Playing Time, and the Genre of the Game Being Played

Objective Psychobiological traits may be associated with excessive Internet use. This study assessed the relationships between biogenetic traits, the amount of time spent in online game playing, and the genre of the online game being played. Methods Five hundred sixty five students who enjoyed one of the four types of games included in this study were recruited. The types of games examined included role playing games (RPG), real-time strategy games (RTS), first person shooting games (FPS), and sports games. Behavioral patterns of game play, academic performance, and player biogenetic characteristics were assessed. Results The amount of time that the participants spent playing online games was significantly greater on weekends than on weekdays. On weekends, the types of games with the largest numbers of participants who played games for more than three hours were ranked as follows: RPG and FPS, RTS, and sports games. The Youngs Internet Addiction Scale (YIAS)score for the RPG group was the highest among the groups of the four types of game players. The time that participants spent playing games on weekdays was negatively associated with academic performance, especially for the RPG and FPS groups. Compared with the other groups, the RPG and RTS groups had higher novelty seeking (NS) scores and self-directedness (SD) scores, respectively. Additionally, the sports game group had higher reward dependency scores than the other groups. Conclusion These results suggest that RPGs may have specific factors that are attractive to latent game addicts with higher NS scores. Additionally, excessive playing of online games is related to impaired academic performance.

Effects of brain-derived neurotrophic factor-catecholamine-O-methyltransferase gene interaction on schizophrenic symptoms

The methionine variant of Val66Met brain-derived neurotrophic factor (BDNFmet) and catecholamine-O-methyltransferase (COMTL) is associated with a deficit in attention and aggravation of delusions in schizophrenia. We hypothesized that the BDNF–COMT gene interaction would affect the symptoms and cognition in schizophrenia. Ninety-six schizophrenic patients and 79 control participants were recruited. The patients who were BDNFmet/met×COMTL carriers had the highest scores of delusion of Positive Symptoms and the Scale for Assessment of Negative Symptoms, word reading of the color word test, and trail-making test B time, compared with the other three genotype interactions. The current results suggest that patients with the BDNFmet/met×COMTL allele had more delusional symptoms and poorer cognitive flexibility, compared with the other three genotype interactions.

Activation of extracellular signal-regulated kinase signaling by chronic electroconvulsive shock in the rat frontal cortex.

The effects of chronic electroconvulsive shock (ECS), given daily for 1, 5 and 10 days, on the activation of extracellular signal-regulated kinase (ERK) were studied in the rat frontal cortex. The phosphorylation of MEK1/2 and ERK1/2 increased through 5 days of ECS. Thereafter, a plateau was achieved. The expression of brain-derived neurotrophic factor was continuously increased for 10 days. Our data show that the effect of ECS on ERK1/2 signaling is increased with chronic treatment.