Serum folate levels in bipolar disorder: a systematic review and meta-analysis.

BACKGROUND: Bipolar disorder (BD) is a major psychiatric illness, however its physiopathology is unclear. The role of folate in the physiopathology of BD is controversial. We conducted this systematic review and meta-analysis to investigate the effect of folate in BD patients. METHODS: We performed a thorough literature study of the PubMed, Embase, ScienceDirect, ClinicalKey, Cochrane Library, ProQuest, Web of Science, and ClinicalTrials.gov databases until December 21st, 2018. Random effects meta-analysis was conducted. RESULTS: Six articles involving 481 patients with BD and 760 controls were included. The meta-analysis results suggested that serum folate levels in the patients with BD were significantly lower than those in the controls (Hedges' g = - 0.211, 95% confidence interval = - 0.391 to - 0.031, p = 0.021). CONCLUSION: The current meta-analysis show it might be association between lower serum folate levels and patient with BD. However, we could not distinguish the potentially confounding effects of mood states on the folate levels. Further prospective studies including subjects with different mood states and possible physiopathology are warranted to investigate the association between folate deficiency and the etiology of BD.

Au Nanoparticles Deposited on Magnetic Carbon Nanofibers as the Ultrahigh Sensitive Substrate for Surface-Enhanced Raman Scattering: Detections of Rhodamine 6G and Aromatic Amino Acids.

Surface-enhanced Raman scattering (SERS) is a unique spectroscopy that can offer high-sensitive detection for many molecules. Herein, the Au particles deposited on carbon nanofiber-encapsulated magnetic Ni nanoparticles (NPs) (Ni@CNFs@Au) have been successfully synthesized for SERS measurements. The Ni@CNFs@Au substrates have the advantages of a high SERS sensitivity and good magnetic response. The Ni@CNFs could be directly obtained from CO2 hydrogenation on a Ni catalyst, which has been characterized as having rich carboxylic acid groups, graphitic structures, and a high surface area. The Ni@CNFs surface could effectively increase the density of hotspots during Au NP aggregation and influence the morphology of the Au nanostructures. The spherical shape, oval shape, and coral-like Au nanostructures were prepared on Ni@CNFs with various Au concentrations. Brunauer-Emmett-Teller, zeta potential, high-resolution transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy measurements were used to characterize the Ni@CNFs@Au samples. The Au NPs deposited on the Ni@CNFs presented a suitable oval shape, and an average size of ∼30-40 nm. The size allowed surprisingly ultrasensitive SERS detection of rhodamine 6G (R6G) with a resolution of approximately a single molecule under an excitation wavelength of 532 nm. Using 785 nm excitation, a low R6G concentration of ∼1 × 10-14 M was detected. Moreover, the Ni@CNFs@Au substrates could be rapidly magnetically separated after adsorption. Phenylalanine and tyrosine amino acids, which are associated with the liver disease, were examined using SERS with the Ni@CNFs@Au substrate. Ultralow concentrations of ∼1 × 10-11 M for phenylalanine and ∼1 × 10-13 M for tyrosine were clearly measured. The Ni@CNFs@Au substrates exhibited applicability as excellent SERS detection platforms that combine high-sensitivity and rapid magnetic separation for various adsorption molecules.

Factors affecting the dose of methadone among patients receiving methadone maintenance therapy in Taiwan.

BACKGROUND: Methadone maintenance treatment (MMT) has been shown to be an effective therapeutic strategy for opioid users. This study aimed to investigate the predictive effect of clinically predominant sleep disturbance (CPSD) on the dose of methadone among opiate users receiving MMT during a follow-up period of 6 years in Taiwan. METHODS: This retrospective study included 1,290 individuals with opioid dependence who visited our MMT clinic for the first time. Generalized estimating equations were used to analyze the effect of CPSD on the daily dose of methadone by controlling for the effects of demographic and MMT characteristics. RESULTS: A total of 469 (36.4%) participants were comorbid with CPSD. After controlling for the effects of demographic and MMT characteristics, the participants comorbid with CPSD had a higher dose of daily methadone than those without CPSD (estimate: 7.03, p < .001). Furthermore, younger age (estimate: -1.22, p < .001), older age at initial MMT (estimate: .44, p < .001), lower educational level (estimate: -.90, p = .003) and lower attendance rates (estimate: -.14, p = .033) are significantly related to higher doses of daily methadone. CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE: Our study provided a naturalistic observation of the cohort for long period, along with a large sample size which could reflect clinical practice in the real world. We reported that a higher daily dose of methadone was significantly associated with CPSD after controlling for the effects of other factors. CPSD should be routinely surveyed among heroin users receiving MMT. (Am J Addict 2018;27:225-230).

Altered gray matter volume and disrupted functional connectivity of dorsolateral prefrontal cortex in men with heroin dependence.

AIM: Chronic heroin use can cause various neuropathological characteristics that may compromise brain function. The present study evaluated the alteration of gray matter volume (GMV) and its resting-state functional connectivity (rsFC) over the dorsolateral prefrontal cortex (DLPFC) among male heroin users. METHODS: Thirty heroin-dependent men undergoing methadone maintenance therapy and 30 educational-level- and age-matched male controls were recruited for this study. To assess their GMV and rsFC, the participants were evaluated using spoiled gradient echo and gradient-recalled echo planar imaging sequences with a 3-Tesla General Electric MR scanner under resting state. RESULTS: The heroin-dependent men showed lower GMV over the right DLPFC in comparison with the controls. Further evaluation of the rsFC of the right DLPFC revealed a marked decrease in interhemispheric DLPFC connectivity among those with heroin dependence under control of head movement and GMV of the right DLPFC. CONCLUSION: Although the mechanism remains unclear, the present study shows that chronic heroin use is associated with alteration of morphology as well as rsFC over the right DLPFC. As the DLPFC plays an imperative role in various domains of cognitive function, service providers for heroin users should consider the impacts of possible DLPFC-related cognitive deficits on treatment effectiveness.

Heroin craving and its correlations with clinical outcome indicators in people with heroin dependence receiving methadone maintenance treatment.

BACKGROUND: Craving for substance use has been added as one of the diagnostic criteria of substance use disorders in DSM-5. However, further research is necessary to examine and expand the clinical potential of craving in the assessment and treatment for heroin users. This study aimed to examine the psychometrics of the Desire for Drug Questionnaire-Chinese Mandarin version (DDQ-CM) and its clinical utility of assessing craving for heroin measured among heroin users with methadone maintenance treatment (MMT). METHOD: Self-reported craving for heroin use was measured on the DDQ-CM and visual analog scale among 314 intravenous heroin users receiving MMT. Self-reported heroin dependence, attitude toward heroin use, readiness to change heroin use, and depression were collected. RESULTS: The results found that although the original three-factor model was acceptable for applying the DDQ-CM for heroin users with MMT, only the concurrent validity of the subscales of Desire and Intention and Negative Reinforcement was supported but not that of Control. Meanwhile, the levels of craving on the subscales of Desire and Intention and of Negative Reinforcement on the DDQ-CM were positively associated with the levels of heroin dependence, positive and negative attitudes toward heroin use, and depression, but negatively associated with readiness to change heroin use. CONCLUSIONS: This study supported the application of the subscales of Desire and Intention and Negative Reinforcement on the DDQ-CM to measure heroin craving in Taiwanese-Chinese heroin users and supported the clinical implication of craving in heroin users with MMT.

Cancer in patients with schizophrenia: What is the next step?

People with schizophrenia, who constitute approximately 0.3-1% of the general population, have a nearly 20% shorter life expectancy than the general population. The incidence of varied types of cancers in patients with schizophrenia is controversial. The majority of previous research has demonstrated that patients who have schizophrenia and cancer have early mortality compared to the general population with cancer. The causes of early mortality in patients with schizophrenia and cancer might be attributed to a lower cancer screening rate and lack of effective treatment, including: (i) patient factors, such as poor lifestyle, passive attitude toward treatment, or comorbidity; (ii) physician factors, such as physician bias, which may decrease the delivery of care for individuals with mental disorders; and (iii) hospital administration factors, such as stigma and discrimination. Additional studies on patients with schizophrenia and cancer are warranted and should include the following: a comprehensive review of previous studies; a focus on differentiating the specific types of cancer; and methods for improvement. To decrease the early mortality of patients with schizophrenia, the following measures are proposed: (i) enhance early detection and early treatment, such as increasing the cancer screening rate for patients with schizophrenia; (ii) provide effective, timely treatment and rehabilitation; (iii) improve patients' psychiatric symptoms and cognitive impairment; (iv) promote healthy behavior in the general population and emphasize healthy lifestyles in vulnerable populations; and (v) remove the stigma of schizophrenia. To reduce disparities in physical health, public health strategies and welfare policies must continue to focus on this group of patients.

Explicit and implicit heroin-related cognitions and heroin use among patients receiving methadone maintenance treatment.

BACKGROUND: Craving is an important issue in substance use disorder. To achieve a better understanding of the cognitive processing systems of craving, the cognitive processes of craving have been considered as two distinct processes. One system, based on rule-based inferences and named explicit cognition, is more conscious and effortful. The other system, based on prior learned association and named implicit cognition, is unconscious and effortless. How explicit and implicit cognitions are associated with heroin use in patients with methadone maintenance treatment (MMT) is not clear. This study aimed to explore the relationship between explicit and implicit cognition and heroin use in patients undergoing MMT. METHOD: This study recruited one-hundred forty intravenous heroin users. The participants were invited to provide social-demographic data, the severity of substance dependence and explicit cognition with regard to heroin. Then, participants completed a computerized test to assess implicit cognition with regards to heroin. RESULTS: This study found that explicit and implicit heroin-related cognitions were associated with the frequency of heroin use. There was an interaction effect between implicit and explicit cognition on the frequency of heroin use. This study also found that higher explicit heroin-related cognition was a risk factor for continuing heroin use. CONCLUSION: Both explicit and implicit cognitions were associated with the frequency of heroin use in patients undergoing MMT, but only explicit cognition was associated with whether patients could stop using heroin during MMT. Therefore, the status of heroin use in patients undergoing MMT may be related to different cognitive processes.

Comparison of outcomes after 3-month methadone maintenance treatment between heroin users with and without HIV infection: a 3-month follow-up study.

BACKGROUND: The aim of this study was to compare the changes in primary (heroin use-related) and secondary (depressive symptoms and quality of life, QOL) outcome indicators of 3-month methadone maintenance treatment (MMT) between heroin users with and without HIV infection. METHODS: A total of 242 intravenous heroin-dependent individuals (30 with and 212 without HIV infection) receiving MMT were recruited. Primary (severity of heroin dependence, harm caused by heroin use and current heroin use) and secondary (depressive symptoms and QOL) outcome indicators were determined before and after receiving 3-month MMT. Changes in primary and secondary outcome indicators between the two groups were compared using mixed-model analysis. RESULTS: Heroin users both with and without HIV infection showed significant improvement in three primary outcome indicators after 3-month MMT, and there was no difference in the changes of these primary outcome indicators between the two groups. However, improvements in depressive symptoms and the physical domain of QOL among HIV-infected heroin users were poorer than in those without HIV infection. CONCLUSIONS: The results of this study indicated that heroin users with HIV infection did improve in the primary but not the secondary outcomes after 3-month MMT.

Differences between patients with schizophrenia with and without co-occurring methamphetamine use disorders in a Taiwanese public psychiatric hospital.

This study aimed to examine the factors related to and the outcomes of schizophrenic patients with co-occurring methamphetamine use disorders (MUDs). All schizophrenic patients discharged from a psychiatric hospital between January 1, 2006, and December 31, 2006, were monitored. This study compared the important demographic and clinical variables between patients with co-occurring MUDs and those without, and postdischarge measured time to rehospitalization during a 1-year period. Seven hundred fifty-six patients were included in this study. Of these patients, 88 (11.6%) reported the use of methamphetamine. Univariate analyses indicated that male sex, low educational level, discharge against medical advice, missed first appointment after discharge, co-occurring other illicit substance use disorder, age (younger), diazepam equivalents prescribed at discharge (higher), number of previous admissions within the past 5 years (higher), and length of hospital stay (longer) were predictive of patients with co-occurring MUDs. There were also significant differences in time to rehospitalization between these two groups during the follow-up periods. Many factors can be identified in schizophrenic patients with co-occurring MUDs. Furthermore, schizophrenic patients with co-occurring MUDs were more likely to be rehospitalized. Future studies in many different mental health systems are needed before these findings can be generalized.

Can heroin-dependent individuals benefit from a methadone maintenance treatment program before they drop out against medical advice? A 12-month follow-up study.

AIM: Little is known about whether heroin-dependent individuals receiving methadone maintenance treatment (MMT) who were discharged involuntarily and against medical advice (DAMA) get benefits before they left. The aims of this 12-month follow-up study were to examine whether the effects of MMT on depressive symptoms, heroin dependence and quality of life (QOL) are different among the non-DAMA group, the DAMA group, and the involuntarily discharged group, as well as the time effect of receiving MMT on changes in these three outcome indicators. METHOD: A total of 266 individuals receiving MMT were divided into the non-DAMA group, the DAMA group, and the involuntarily discharged group. Participants were interviewed at baseline and at 3, 6, 9, and 12 months of treatment for levels of depressive symptoms, heroin dependence and QOL. RESULTS: The levels of depressive symptoms, heroin dependence and QOL in all three groups improved after receiving MMT for 3 months and the improvement was maintained during the MMT period. There were no significant differences in the three outcome indicators among the three groups. CONCLUSION: The results support the concept that heroin-dependent individuals benefit from MMT, even if they do not want to stay in the program or drop out involuntarily.

Predictors for dropping-out from methadone maintenance therapy programs among heroin users in southern Taiwan.

This study examined the methadone maintenance therapy (MMT) retention rates of heroin users in Taiwan and the predictors for dropout in the 18-month period after starting MMT. We consecutively recruited 368 intravenous heroin users receiving MMT in 2007-2008 and applied Cox proportional hazards regression analysis to determine the predictive effect of pre- and in-treatment variables on early discontinuation of MMT. The retention rate at 18 months was 32.3%. High heroin expenses, more severe harm caused by heroin use, perceived lower family support, and lower methadone dosage at 3 months after starting MMT increased the risk of dropout in the follow-up period.

Effects of heart rate variability biofeedback (HRVBFB) on sleep quality and depression among methamphetamine users.

Methamphetamine is garnering concern due to its increasing use worldwide. Depression and sleep quality are major mental health issues in substance users. Heart rate variability biofeedback (HRVBFB) has shown promising results in terms of reducing depression and increasing sleep quality. The present study aimed to explore the effects of HRVBFB on these two issues in methamphetamine users. Sixty-one methamphetamine users were enrolled and allocated randomly into a treatment as usual (TAU) group and a HRVBFB plus TAU group. The levels of depressive symptoms and sleep quality were assessed at intake, end of the intervention, and end of follow-up. Compared with baseline, the levels of depressive symptoms and poor sleep quality were decreased at the end of the intervention and follow-up in the HRVBFB group. The HRVBFB group exhibited a greater decrease in depressive symptoms and a better improvement in sleep quality than the TAU group. The associations of HRV indices with levels of depressive symptoms and poor sleep quality were different in the two groups. Our results showed that HRVBFB is a promising intervention for reducing depressive symptoms and improving sleep quality in methamphetamine users. The benefits with respect to depressive symptoms and poor sleep quality can extend beyond the end of HRVBFB intervention.

The influence of apolipoprotein E Epsilon4 polymorphism on qEEG profiles in healthy young females: a resting EEG study.

The epsilon4 allele of the Apolipoprotein E (ApoE) gene has been linked to various neurological conditions and the aging process in the elderly. However, evidence has suggested that the influence of ApoE epsilon4 may commence in early life. This study examined the modulatory effects of ApoE epsilon4 on regional neural activity as well as inter-regional neural interactions in a young population aged 19-21. Blood samples and resting state eyes-closed EEG signals were collected from 265 healthy females, and stratified into two groups: epsilon4 carriers and non-carriers. The values of the log-transformed mean power of 18 electrodes and the mutual information of 20 channel pairs across delta, theta, alpha and beta frequencies were analyzed. Our connectivity analysis was based on information theory, which combined Morlet wavelet transform and mutual information calculation. Between-group statistics were performed by independent t-test. We notice a consistent trend across the brain, in which ApoE epsilon4 carriers possess lower regional power at the alpha band. The epsilon4 allele is also associated with lower regional power at the theta frequency in the left frontal and posterior brain regions. Functional connectivity analyses reveal a right-lateralized network that differentiates epsilon4 carriers and non-carriers, with lower connectivity strengths for the former. Our tonic EEG analyses complement those of previous reports in that the ApoE epsilon4 allele has a negative impact on regional neural synchronization and inter-regional neural interaction.

Change in quality of life and its predictors in heroin users receiving methadone maintenance treatment in Taiwan: an 18-month follow-up study.

BACKGROUND: A good quality of life (QOL) is associated with successful treatment in patients with opioid dependence. Therefore, it is of clinical benefit to examine what factors can predict a change in QOL among heroin users in the course of a methadone maintenance treatment (MMT) program. OBJECTIVES: This longitudinal study aimed to examine the patterns and predictors of change in QOL among heroin users during the period of an 18-month MMT program. METHODS: A total of 368 intravenous heroin users receiving MMT in southern Taiwan between 2007 and 2008 were interviewed using the Taiwan version of the Brief Version of the World Health Organization Quality of Life Instrument (WHOQOL-BREF) at baseline and after 3, 6, 9, 12, 15, and 18 months of treatment. Demographic and substance-use characteristics, severity of heroin use, HIV serostatus, criminal record, and family function data were collected during baseline interviews. Data on methadone dosage at each follow-up point and the duration of retention in the MMT program were also collected. RESULTS: Improvement in QOL was rapid during the first 3 months after initiation of MMT and slowed beyond the 3-month point. A higher dosage of methadone predicted a better QOL. In addition, longer retention in the program may be associated with a better QOL. CONCLUSIONS: The results supported the hypothesis that, regarding QOL, heroin users can benefit rapidly and continuously from a MMT. A higher dose of methadone and longer treatment may predict improvement in QOL. SCIENTIFIC SIGNIFICANCE: Efforts are needed to amend the modifiable factors related to poor QOL for heroin users in MMT programs.

The withdrawal-related affective, gaming urge, and anhedonia symptoms of internet gaming disorder during abstinence.

Aim: The study explores IGD withdrawal-related presentations, including autonomic reaction, affective symptoms, anhedonia, and gaming urge during abstinence from gaming. We prospectively evaluated these withdrawal-related symptoms (WRS) and gaming craving during abstinence from gaming. Methods: We examined 69 individuals with IGD and 69 regular gamers and evaluated their WRS (using an exploratory questionnaire), affective and behavioral WRS (using the Questionnaire on Gaming Urge-Brief Version gaming disorder questionnaire), and heart rate. All the participants attempted to abstain from gaming before our assessment. Subsequently, some participants' WRS and gaming craving before they engaged in gaming were prospectively evaluated. Results: In the IGD group, 85.5% experienced gaming WRS, including affective, anhedonia, and gaming urge symptoms. They could relieve these symptoms through gaming. The IGD group experienced more severe gaming WRS, gaming craving, and a higher heart rate than the regular gamer group. Gaming urge was most associated WRS of IGD. Participants with IGD experienced more severe gaming cravings when their gaming abstinence before the assessment was shorter. WRS attenuated at night and the following morning when they maintained their gaming abstinence after assessment. Conclusion: Individuals with IGD experience withdrawal-related affective, anhedonia, and gaming urge symptoms and a higher heart rate during abstinence. The WRS attenuated in 1 day. Most participants agreed that these symptoms could be relieved through gaming. Further prospective evaluation by objective assessment in an adequate sample was required to understand gaming withdrawal symptoms comprehensively.

Predictors of Workplace Substance Reuse among Patients with Alcohol or Illegal Substance Use Disorder in the Workplace.

Substance and alcohol use in the workplace have become a global health burden; however, the etiologies have seldom been explored. The aims of this study were to develop a Workplace Substance Reuse Questionnaire (WSRQ) to measure the multidimensional factors associated with the reuse of alcohol or illegal substances in the workplace. The predictors of reuse were also investigated. The WSRQs for alcohol (WSRQ-Alc) and illegal substances (WSRQ-Sub) were composed of 15 and 13 items, respectively. Factors associated with workplace substance reuse included workplace environment, workload, social interaction in the workplace and other cues. Construct validity and reliability were performed to verify the questionnaires. Multivariate linear regression was conducted to estimate the associations between the factors and WSRQ score. A total of 90 patients with substance or alcohol use disorder were recruited. The results demonstrated that the WSRQ-Alc and WSRQ-Sub had acceptable reliability, with variance of 76.4% and 75.4%, respectively. The confirmatory factor analysis fit indices also indicated the adequacy of the model. A longer duration of alcohol use (ß = 0.44; p = 0.002) and higher frequencies of changing job (ß = 0.32; p = 0.027) and working part time (ß = 0.32; p = 0.028) were significantly associated with higher WSRQ-Alc score. Our results highlight the importance of abstinence treatment and job referral for individuals with alcohol or substance use. Further studies are warranted to help extend the applicability and generalizability of the WSRQ.

A Pilot Randomized Control Study on Effect Brief Heart Rate Variability Biofeedback as a Complementary Treatment in Men with Methamphetamine Use Disorder.

The aims of this study were to investigate the efficacy of heart rate variability biofeedback (HRVBFB) intervention in terms of reducing craving, severity of dependence, and rate of positive methamphetamine urine testing in men taking part in a methamphetamine use disorder outpatient treatment program. Sixty-one adult men received either HRVBFB treatment plus treatment as usual (TAU) over four weeks or TAU only. Men receiving HRVBFB showed significantly greater reductions in craving, dependence severity, and the rate of positive methamphetamine urine testing at the end of the intervention and four weeks of follow-up. The analyses further showed that the levels of craving and dependence severity at treatment entry were predictive of changes in craving and dependence severity at the end of treatment and follow-up, respectively. The baseline status of a positive methamphetamine urine test only predicted a positive methamphetamine urine test at the end of treatment, not at the end of the follow-up period. Our results showed HRVBFB intervention has merits as an adjunct treatment to ameliorate cravings and reduce the severity of dependence experienced by persons with methamphetamine use disorder. An added value of HRVBFB intervention is the fact that it can be easily and affordably implemented in everyday life.

Do resting brain dynamics predict oddball evoked-potential?

BACKGROUND: The oddball paradigm is widely applied to the investigation of cognitive function in neuroscience and in neuropsychiatry. Whether cortical oscillation in the resting state can predict the elicited oddball event-related potential (ERP) is still not clear. This study explored the relationship between resting electroencephalography (EEG) and oddball ERPs. The regional powers of 18 electrodes across delta, theta, alpha and beta frequencies were correlated with the amplitude and latency of N1, P2, N2 and P3 components of oddball ERPs. A multivariate analysis based on partial least squares (PLS) was applied to further examine the spatial pattern revealed by multiple correlations. RESULTS: Higher synchronization in the resting state, especially at the alpha spectrum, is associated with higher neural responsiveness and faster neural propagation, as indicated by the higher amplitude change of N1/N2 and shorter latency of P2. None of the resting quantitative EEG indices predict P3 latency and amplitude. The PLS analysis confirms that the resting cortical dynamics which explains N1/N2 amplitude and P2 latency does not show regional specificity, indicating a global property of the brain. CONCLUSIONS: This study differs from previous approaches by relating dynamics in the resting state to neural responsiveness in the activation state. Our analyses suggest that the neural characteristics carried by resting brain dynamics modulate the earlier/automatic stage of target detection.

The influence of serotonin transporter polymorphisms on cortical activity: a resting EEG study.

BACKGROUND: The serotonin transporter gene (5-HTT) is a key regulator of serotonergic neurotransmission and has been linked to various psychiatric disorders. Among the genetic variants, polymorphisms in the 5-HTT gene-linked polymorphic region (5-HTTLPR) and variable-number-of-tandem-repeat in the second intron (5-HTTVNTR) have functional consequences. However, their genetic impact on cortical oscillation remains unclear. This study examined the modulatory effects of 5-HTTLPR (L-allele carriers vs. non-carriers) and 5-HTTVNTR (10-repeat allele carriers vs. non-carriers) polymorphism on regional neural activity in a young female population. METHODS: Blood samples and resting state eyes-closed electroencephalography (EEG) signals were collected from 195 healthy women and stratified into 2 sets of comparisons of 2 groups each: L-allele carriers (N=91) vs. non-carriers for 5-HTTLPR and 10-repeat allele carriers (N=25) vs. non-carriers for 5-HTTVNTR. The mean power of 18 electrodes across theta, alpha, beta, gamma, gamma1, and gamma2 frequencies was analyzed. Between-group statistics were performed by an independent t-test, and global trends of regional power were quantified by non-parametric analyses. RESULTS: Among 5-HTTVNTR genotypes, 10-repeat allele carriers showed significantly low regional power at gamma frequencies across the brain. We noticed a consistent global trend that carriers with low transcription efficiency of 5-HTT possessed low regional powers, regardless of frequency bands. The non-parametric analyses confirmed this observation, with P values of 3.071×10-8 and 1.459×10-12 for 5-HTTLPR and 5-HTTVNTR, respectively. CONCLUSIONS AND LIMITATIONS: Our analyses showed that genotypes with low 5-HTT activity are associated with less local neural synchronization during relaxation. The implication with respect to genetic vulnerability of 5-HTT across a broad range of psychiatric disorders is discussed. Given the low frequency of 10-repeat allele of 5-HTTVNTR in our research sample, the possibility of false positive findings should also be considered.