Effects of Transcranial Direct Current Stimulation on Attentional Bias to Methamphetamine Cues and Its Association With EEG-Derived Functional Brain Network Topology.

BACKGROUND: Although transcranial direct current stimulation (tDCS) has shown to potentially mitigate drug craving and attentional bias to drug-related stimuli, individual differences in such modulatory effects of tDCS are less understood. In this study, we aimed to investigate a source of the inter-subject variability in the tDCS effects that can be useful for tDCS-based treatments of individuals with methamphetamine (MA) use disorder (IMUD). METHODS: Forty-two IMUD (all male) were randomly assigned to receive a single-session of either sham or real bilateral tDCS (anodal right/cathodal left) over the dorsolateral prefrontal cortex. The tDCS effect on MA craving and biased attention to drug stimuli were investigated by quantifying EEG-derived P3 (a measure of initial attentional bias) and late positive potential (LPP; a measure of sustained motivated attention) elicited by these stimuli. To assess the association of changes in P3 and LPP with brain connectivity network (BCN) topology, the correlation between topology metrics, specifically those related to the efficiency of information processing, and the tDCS effect was investigated. RESULTS: The P3 amplitude significantly decreased following the tDCS session, whereas the amplitudes increased in the sham group. The changes in P3 amplitudes were significantly correlated with communication efficiency measured by BCN topology metrics (r = -0.47, P = .03; r = -0.49, P = .02). There was no significant change in LPP amplitude due to the tDCS application. CONCLUSIONS: These findings validate that tDCS mitigates initial attentional bias, but not the sustained motivated attention, to MA stimuli. Importantly, however, results also show that the individual differences in the effects of tDCS may be underpinned by communication efficiency of the BCN topology, and therefore, these BCN topology metrics may have the potential to robustly predict the effectiveness of tDCS-based interventions on MA craving and attentional bias to MA stimuli among IMUD.

Disrupted resting-state brain functional network in methamphetamine abusers: A brain source space study by EEG.

This study aimed to examine the effects of chronic methamphetamine use on the topological organization of whole-brain functional connectivity network (FCN) by reconstruction of neural-activity time series at resting-state. The EEG of 36 individuals with methamphetamine use disorder (IWMUD) and 24 normal controls (NCs) were recorded, pre-processed and source-reconstructed using standardized low-resolution tomography (sLORETA). The brain FCNs of participants were constructed and between-group differences in network topological properties were investigated using graph theoretical analysis. IWMUD showed decreased characteristic path length, increased clustering coefficient and small-world index at delta and gamma frequency bands compared to NCs. Moreover, abnormal changes in inter-regional connectivity and network hubs were observed in all the frequency bands. The results suggest that the IWMUD and NCs have distinct FCNs at all the frequency bands, particularly at the delta and gamma bands, in which deviated small-world brain topology was found in IWMUD.

Socio-Demographic Determinants of Health-Related Quality of Life in Tehran Lipid and Glucose Study (TLGS).

BACKGROUND: Health-related quality of life (HRQOL) is a multi-dimensional concept that is affected by different variables. A large body of evidence shows that socio-demographic factors have a significant influence on HRQOL. When considering differences in cultural contexts and social values of various countries and the lack of evidence regarding socio-demographic determinants of HRQOL among the Iranian general population, it is important to verify the main socio-demographic determinants of HRQOL in an urban Iranian population. OBJECTIVES: This study aimed to explore socio-demographic factors associated with HRQOL and to ascertain the determinants of poor HRQOL in participants of the Tehran lipid and glucose study (TLGS). METHODS: The participants included 3491 adults, aged ≥ 20 years, who had participated in the TLGS. To obtain socio-demographic and HRQOL information, participants were interviewed by trained interviewers. Mean HRQOL scores were compared using the student's t test and analysis of variance (ANOVA). To determine significant determinants of poor HRQOL, multivariate logistic regression analysis was performed. RESULTS: Mean ages of males and females were 47.7 ± 15.6 and 47.8 ± 14.2 years, respectively and 58.6% of participants were male. Males had significantly higher scores compared to females in both the physical and mental domains of HRQOL (P < 0.001). In males, significant determinants of poor physical HRQOL were older age, being married, being unemployed yet having other sources of income, having literacy levels below high school diploma, and having chronic diseases (P < 0.05). In females, however older age and being housewives were significant determinants of poor physical HRQOL (P < 0.05). In addition, significant determinants of poor mental HRQOL were younger age and being single or divorced/widowed in males and younger age and being illiterate as well as having literacy levels below high school diploma in females (P < 0.05). CONCLUSIONS: Current findings highlight the importance of socio-demographic determinants of HRQOL in both genders, specifically in the physical domain, and demonstrate their roles to be more prominent in males. These findings highlight gender-specific associations between socio-demographic factors and various aspects of HRQOL among the TLGS population, which could be applied in future research focusing on non-communicable diseases and planning health promotion programs.

The Persian Checklist of Pleasant Events (PCPE): Development, Validity and Reliability.

OBJECTIVE: Experiencing pleasant events during daily life has a significant positive role in the personal mental health and acts as a keystone for "behavioral activation" (BA) interventions. There are serious differences in the pleasant event schedules in different cultures and countries. We aimed to develop a Persian checklist of pleasant events (PCPE) to provide and validate a culturally compatible checklist for Iranians. METHODS: To develop a checklist of pleasant events, inspired by Pleasant Events Schedule (PES) (MacPhillamy & Lewinsohn, 1982), we held three focused group discussions with 24 normal healthy participants from both genders (female = 12) and asked them to mention as much pleasant events as possible. When the list reached saturation level, the inappropriate items with respect to legal, cultural and religious concerns were omitted. The final checklist of PCPE consists of two subscales: Frequency (frequency of events during last month) and pleasantness (perceived pleasantness of events). The total score consists of frequency multiplied by pleasantness. To test the reliability and validity of the checklist, the PCPE, Depression, Anxiety and Stress Scale (DASS), the Persian version of WHO Quality of Life and the Demographic Questionnaire were administered in a sample of 104 participants (50 male and 54 female). RESULTS: Frequency, pleasantness and the total scores of PCPE showed high levels of internal consistency (Cronbach's alpha, .976, .976 & .974, respectively). Further support for the convergent validity of the PCPE was obtained via moderate negative correlations with depression, anxiety, stress scores in DASS and positive correlation with quality of life as well as respondent's perceived happiness. There were negative correlations between frequency, pleasantness and total scores and age of the participants (Pearson correlation coefficient, r = -.194, p<0.05; r = -.270, p<0.01 & r = -.234, p<0.05, respectively). Conclusion : PCPE as an assessment tool has shown to have good reliability and validity among Iranians. Further steps should be taken to validate this instrument in different psychopathologies such as depression, addiction and obesity. .