Jae Yeon Hwang

Altered Brain Activity during Reward Anticipation in Pathological Gambling and Obsessive-Compulsive Disorder

Background Pathological gambling (PG) and obsessive-compulsive disorder (OCD) are conceptualized as a behavioral addiction, with a dependency on repetitive gambling behavior and rewarding effects following compulsive behavior, respectively. However, no neuroimaging studies to date have examined reward circuitry during the anticipation phase of reward in PG compared with in OCD while considering repetitive gambling and compulsion as addictive behaviors. Methods/Principal Findings To elucidate the neural activities specific to the anticipation phase of reward, we performed event-related functional magnetic resonance imaging (fMRI) in young adults with PG and compared them with those in patients with OCD and healthy controls. Fifteen male patients with PG, 13 patients with OCD, and 15 healthy controls, group-matched for age, gender, and IQ, participated in a monetary incentive delay task during fMRI scanning. Neural activation in the ventromedial caudate nucleus during anticipation of both gain and loss decreased in patients with PG compared with that in patients with OCD and healthy controls. Additionally, reduced activation in the anterior insula during anticipation of loss was observed in patients with PG compared with that in patients with OCD which was intermediate between that in OCD and healthy controls (healthy controls < PG < OCD), and a significant positive correlation between activity in the anterior insula and South Oaks Gambling Screen score was found in patients with PG. Conclusions Decreased neural activity in the ventromedial caudate nucleus during anticipation may be a specific neurobiological feature for the pathophysiology of PG, distinguishing it from OCD and healthy controls. Correlation of anterior insular activity during loss anticipation with PG symptoms suggests that patients with PG fit the features of OCD associated with harm avoidance as PG symptoms deteriorate. Our findings have identified functional disparities and similarities between patients with PG and OCD related to the neural responses associated with reward anticipation.

Dysfunctional inhibitory control and impulsivity in Internet addiction

The purpose of this study was to explore a psychological profile of Internet addiction (IA) considering impulsivity as a key personality trait and as a key component of neuropsychological functioning. Twenty three subjects with IA (Youngs Internet Addiction Test scores=70 or more) and 24 sex-, age-, and intelligence-matched healthy controls were enrolled. Participants filled out a questionnaire about trait impulsivity, the Trait Characteristic Inventory, depression, and anxiety. Next, we administered traditional neuropsychological tests including the Stroop et al. and computerized neuropsychological tests using the Cambridge Neuropsychological Test Automated Battery. The IA group exhibited more trait impulsivity than the healthy control group. They also scored higher for novelty seeking and harm avoidance. The IA group performed more poorly than the healthy control group in a computerized stop signal test, a test for inhibitory function and impulsivity; no group differences appeared for other neuropsychological tests. The IA group also scored higher for depression and anxiety, and lower for self-directedness and cooperativeness. In conclusion, individuals with IA exhibited impulsivity as a core personality trait and in their neuropsychological functioning.

Resting-state beta and gamma activity in Internet addiction.

Internet addiction is the inability to control ones use of the Internet and is related to impulsivity. Although a few studies have examined neurophysiological activity as individuals with Internet addiction engage in cognitive processing, no information on spontaneous EEG activity in the eyes-closed resting-state is available. We investigated resting-state EEG activities in beta and gamma bands and examined their relationships with impulsivity among individuals with Internet addiction and healthy controls. Twenty-one drug-naïve patients with Internet addiction (age: 23.33 ± 3.50 years) and 20 age-, sex-, and IQ-matched healthy controls (age: 22.40 ± 2.33 years) were enrolled in this study. Severity of Internet addiction was identified by the total score on Youngs Internet Addiction Test. Impulsivity was measured with the Barratt Impulsiveness Scale-11 and a stop-signal task. Resting-state EEG during eyes closed was recorded, and the absolute/relative power of beta and gamma bands was analyzed. The Internet addiction group showed high impulsivity and impaired inhibitory control. The generalized estimating equation showed that the Internet-addiction group showed lower absolute power on the beta band than did the control group (estimate = -3.370, p < 0.01). On the other hand, the Internet-addiction group showed higher absolute power on the gamma band than did the control group (estimate = 0.434, p < 0.01). These EEG activities were significantly associated with the severity of Internet addiction as well as with the extent of impulsivity. The present study suggests that resting-state fast-wave brain activity is related to the impulsivity characterizing Internet addiction. These differences may be neurobiological markers for the pathophysiology of Internet addiction.

Shared psychological characteristics that are linked to aggression between patients with Internet addiction and those with alcohol dependence

BackgroundInternet addiction (IA) is considered as one of behavioral addictions. Although common neurobiological mechanisms have been suggested to underlie behavioral addiction and substance dependence, few studies have directly compared IA with substance dependence, such as alcohol dependence (AD).MethodsWe compared patients with IA, AD, and healthy controls (HC) in terms of the Five Factor Model of personality and with regard to impulsiveness, anger expression, and mood to explore psychological factors that are linked to aggression. All patients were treatment-seeking and had moderate-to-severe symptoms.ResultsThe IA and AD groups showed a lower level of agreeableness and higher levels of neuroticism, impulsivity, and anger expression compared with the HC group, which are characteristics related to aggression. The addiction groups showed lower levels of extraversion, openness to experience, and conscientiousness and were more depressive and anxious than the HCs, and the severity of IA and AD symptoms was positively correlated with these types of psychopathology.ConclusionsIA and AD are similar in terms of personality, temperament, and emotion, and they share common characteristics that may lead to aggression. Our findings suggest that strategies to reduce aggression in patients with IA are necessary and that IA and AD are closely related and should be dealt with as having a close nosological relationship.

Differential resting-state EEG patterns associated with comorbid depression in Internet addiction

OBJECTIVE Many researchers have reported a relationship between Internet addiction and depression. In the present study, we compared the resting-state quantitative electroencephalography (QEEG) activity of treatment-seeking patients with comorbid Internet addiction and depression with those of treatment-seeking patients with Internet addiction without depression, and healthy controls to investigate the neurobiological markers that differentiate pure Internet addiction from Internet addiction with comorbid depression. METHOD Thirty-five patients diagnosed with Internet addiction and 34 age-, sex-, and IQ-matched healthy controls were enrolled in this study. Patients with Internet addiction were divided into two groups according to the presence (N=18) or absence (N=17) of depression. Resting-state, eye-closed QEEG was recorded, and the absolute and relative power of the brain were analyzed. RESULTS The Internet addiction group without depression had decreased absolute delta and beta powers in all brain regions, whereas the Internet addiction group with depression had increased relative theta and decreased relative alpha power in all regions. These neurophysiological changes were not related to clinical variables. CONCLUSION The current findings reflect differential resting-state QEEG patterns between both groups of participants with Internet addiction and healthy controls and also suggest that decreased absolute delta and beta powers are neurobiological markers of Internet addiction.

Pharmacotherapy and clinical characteristics of ultra-high-risk for psychosis according to conversion status: a naturalistic observational study

Aim: To explore the differences in pharmacotherapy and clinical characteristics of individuals at ultra‐high‐risk (UHR) for psychosis according to the conversion status, we analyzed the data for UHR patients seen at the Seoul Youth Clinic.

No association between AKT1 polymorphism and schizophrenia: A case–control study in a Korean population and a meta-analysis

V-akt murine thymoma viral oncogene homolog 1 (AKT1) has been suggested to be involved in the pathophysiology of schizophrenia. Recent, independent studies in Caucasian, Japanese, Iranian, and Chinese populations have reported that the AKT1 gene may be associated with schizophrenia, but these results have yet to be replicated in other populations. In the present study, we performed a case-control association study between AKT1 and schizophrenia in a Korean population. We genotyped six single nucleotide polymorphisms (SNP1 (rs3803300), SNP2 (rs1130214), SNP3 (rs3730358), SNP4 (rs1130233), SNP5 (rs2494732), SNP A (rs2498804)) of AKT1, selected from previous reports, in a sample of 283 subjects with schizophrenia and 350 controls. No significant difference in single marker polymorphisms or haplotype frequencies of the six SNPs in the AKT1 gene was observed between controls and subjects with schizophrenia. In addition, we carried out an updated meta-analysis of the six SNPs, and found no evidence for an association between the six SNPs and schizophrenia. Taken together, our results do not support the hypothesis that AKT1 is a susceptibility gene for schizophrenia.

Clinical and neurocognitive profiles of subjects at high risk for psychosis with and without obsessive–compulsive symptoms

Objective: Obsessive–compulsive symptoms (OCS), which are common in psychotic-spectrum illnesses, are of clinical interest because of their association with poor prognosis or cognitive dysfunction. However, few studies on the clinical and neurocognitive implications of OCS in individuals at ultra-high risk for psychosis (UHR) have been conducted. Method: Sixty-five UHR subjects [24 with OCS (UHR+OCS), 41 without OCS (UHR−OCS)], and 40 healthy controls were assessed using clinical scales and neurocognitive tests. Results: Those with UHR+OCS showed more severe clinical symptoms and poorer global functioning as compared to both healthy controls and the UHR−OCS group, according to the results of the Global Assessment of Functioning, the Comprehensive Assessment of At-Risk Mental States, and the Positive and Negative Syndrome Scale (total, negative, and general scores). In the neurocognitive domain, those in the UHR−OCS group showed notably greater latency in the Stroop task and more confabulation errors in immediate recall in the Rey–Osterrieth Complex Figure Test compared with those in UHR+OCS group, whose performance levels were similar to those of the healthy control group. Conclusions: The OCS manifested in UHR individuals was associated with a more severe clinical symptomatic presentation, including lower global functioning and more psychotic symptoms. On the other hand, those with UHR−OCS performed more poorly on some cognitive tests. The features that distinguish the groups can be used for developing prognoses and intervention strategies for the heterogeneous UHR group.

Comparison of the Effectiveness of Virtual Cue Exposure Therapy and Cognitive Behavioral Therapy for Nicotine Dependence

Previous studies have reported promising results regarding the effect of repeated virtual cue exposure therapy on nicotine dependence. This study aimed to compare the effectiveness of virtual cue exposure therapy (CET) and cognitive behavioral therapy (CBT) for nicotine dependence. Thirty subjects with nicotine dependence participated in 4 weeks of treatment with either virtual CET (n=15) or CBT (n=15). All patients were male, and none received nicotine replacement treatment during the study period. The main setting of the CET used in this study was a virtual bar. The primary foci of the CBT offered were (a) smoking cessation education, (b) withdrawal symptoms, (c) coping with high-risk situations, (d) cognitive reconstruction, and (e) stress management. Daily smoking count, level of expiratory carbon monoxide (CO), level of nicotine dependence, withdrawal symptoms, and subjective craving were examined on three occasions: week 0 (baseline), week 4 (end of treatment), and week 12 (follow-up assessment). After treatment, the daily smoking count, the expiratory CO, and nicotine dependence levels had significantly decreased. These effects continued during the entire study period. Similar changes were observed in both virtual CET and CBT groups. We found no interaction between type of therapy and time of measurement. Although the current findings are preliminary, the present study provided evidence that virtual CET is effective for the treatment of nicotine dependence at a level comparable to CBT.

Effects of clozapine on behavioral sensitization induced by cocaine

Using cocaine-sensitized mice as a model for psychosis, this study investigated whether subchronic treatment with clozapine could affect the sensitized state of the animals and examined the accompanying molecular changes in the brain. To induce sensitization, ICR mice (n=44) were treated with cocaine for 5 days. After 7 days of withdrawal, sensitization was confirmed by a cocaine challenge. Then, the sensitized animals were treated with clozapine for 5 days and rechallenged with cocaine. The frontal cortices were removed from the mice (n=16) 24 h after the last challenge, and the phosphorylation status of some key signaling molecules was investigated. Compared with the sensitized mice receiving the vehicle treatment, the sensitized mice receiving subchronic clozapine showed less locomotor activity, with an activity level similar to that of non-sensitized mice. However, clozapine did not directly affect the stimulatory effect of cocaine. Clozapine also reversed some of the sensitization-induced biochemical changes, including increased phosphorylation of GSK-3beta and CREB, in the frontal cortex. Subchronic treatment with clozapine apparently de-sensitized the sensitized mice. The long-term effect of clozapine on stimulant-induced sensitization may be related to the therapeutic effect of the drug as an antipsychotic agent.