Impulsivity and methamphetamine use

The influence of adverse childhood experiences and depression on addiction severity among methamphetamine users: exploring the role of perseveration

Aims

This investigation aimed to clarify the intricate relationship among depression, cognitive function, adverse childhood experiences (ACEs), and their combined influence on methamphetamine use disorder (MUD).

Methods

Utilizing a battery of psychological tests, this study ascertained the impact of ACEs on the condition of 76 people with MUD who meet the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria, aged 42.17 on average. The Iowa Gambling Task (IGT), Conners' Continuous Performance-II (CPT-II), the self-report Severity of Dependence Scale (SDS), and the Beck Depression Inventory-II (BDI-II) were used for these evaluations. Individuals involved in the study were categorized into two discrete cohorts, mild (ME) and severe (SE), based on the extent of their ACEs exposure. This study employed the PROCESS regression, the independent t-test andχ2 tests for the analysis.

Results

The findings revealed notable discrepancies in the psychological consequences between the two groups with different degrees of ACEs; however, no substantial differences were observed in the demographic parameters. The SE group exhibited elevated BDI-II scores, more evident indications of MUD, and a higher degree of CPT-II cognitive perseveration. The PROCESS model revealed that cognitive perseveration moderated the impact of depression on ACEs and subjective MUD severity, explaining 20.2% of the variance. The ACEs and depression predicted 28.6% of the variance in MUD symptoms. However, no statistically significant differences were detected between the two groups regarding the parameters in the IGT-2 assessment.

Conclusions

These results indicate that the interaction between cognitive and depressive factors mediates the effect of ACEs on subjective MUD severity but not on MUD symptoms. The ACEs significant impact on mental health severity perception is explained by cognitive and depressive factors. This implies that MUD treatment and rehabilitation should address cognitive dysfunction and developmental trauma.

Associations between impulsivity and fecal microbiota in individuals abstaining from methamphetamine

INTRODUCTION

Methamphetamine (MA) abuse is a major public problem, and impulsivity is both a prominent risk factor and a consequence of addiction. Hence, clarifying the biological mechanism of impulsivity may facilitate the understanding of addiction to MA. The microbiota-gut-brain axis was suggested to underlie a biological mechanism of impulsivity induced by MA.

METHODS

We therefore recruited 62 MA addicts and 50 healthy controls (HCs) to investigate the alterations in impulsivity and fecal microbiota and the associations between them in the MA group. Thereafter, 25 MA abusers who abstained from MA for less than 3 months were followed up for 2 months to investigate the relationship between impulsivity and microbiota as abstinence became longer. 16S rRNA sequencing was conducted for microbiota identification.

RESULTS

Elevated impulsivity and dysbiosis characterized by an increase in opportunistic pathogens and a decrease in probiotics were identified in MA abusers, and both the increased impulsivity and disrupted microbiota tended to recover after longer abstinence from MA. Impulsivity was related to microbiota, and the effect of MA abuse on impulsivity was mediated by microbiota.

CONCLUSION

Our findings potentially highlighted the importance of abstention and implicated the significant role of the microbiota-gut-brain axis in the interrelationship between microbiota and behaviors, as well as the potential of microbiota as a target for intervention of impulsivity.

Relationships Between Impulsivity, Methamphetamine use Disorder and Gambling Disorder

Methamphetamine use disorder (MAUD) and gambling disorder (GD) frequently co-occur. Individuals with both conditions are typically more difficult to treat than those with either disorder alone. This study aimed to investigate the co-occurrence and clinical characteristics of people with MAUD and GD. Between March 2018 and August 2020, 350 men with methamphetamine use entering a compulsory drug rehabilitation center in Changsha, Hunan Province received semi-structured interviews. Participants completed the Barratt Impulsiveness Scale-11 and provided information on childhood upbringings and drug use characteristics. Independent sample t-tests compared differences between individuals with MAUD and with and without co-occurring GD. Dichotomous logistic regression was used to statistically predict co-occurring GD. The prevalence of GD was 45.1%. Most individuals (39.1% overall) had post-onset methamphetamine use (PoMAU-GD). The number of MAUD symptoms, history of gambling by family members, age of first sexual activity, and non-planning impulsivity statistically predicted PoMAU-GD, jointly explaining 24.0% of the total variance. The regression model fit well (HLχ2 = 5.503, p = 0.70), in which the specificity was 0.80, the sensitivity was 0.64, and the area under the curve was 0.79 (95%CI: 0.75-0.84). This study clarifies the prevalence of and potential risk factors for GD among individuals engaging in compulsory MAUD treatment in China. The high prevalence and associated clinical features of GD in the MAUD group highlight the importance of screening for GD in this population and intervening accordingly.

Modeling methamphetamine use disorder and relapse in animals: short- and long-term epigenetic, transcriptional., and biochemical consequences in the rat brain

Methamphetamine use disorder (MUD) is a neuropsychiatric disorder characterized by binge drug taking episodes, intervals of abstinence, and relapses to drug use even during treatment. MUD has been modeled in rodents and investigators are attempting to identify its molecular bases. Preclinical experiments have shown that different schedules of methamphetamine self-administration can cause diverse transcriptional changes in the dorsal striatum of Sprague-Dawley rats. In the present review, we present data on differentially expressed genes (DEGs) identified in the rat striatum following methamphetamine intake. These include genes involved in transcription regulation, potassium channel function, and neuroinflammation. We then use the striatal data to discuss the potential significance of the molecular changes induced by methamphetamine by reviewing concordant or discordant data from the literature. This review identified potential molecular targets for pharmacological interventions. Nevertheless, there is a need for more research on methamphetamine-induced transcriptional consequences in various brain regions. These data should provide a more detailed neuroanatomical map of methamphetamine-induced changes and should better inform therapeutic interventions against MUD.

Hyperconnectivity of the lateral amygdala in long-term methamphetamine abstainers negatively correlated with withdrawal duration

Introduction: Several studies have reported structural and functional abnormalities of the amygdala caused by methamphetamine addiction. However, it is unknown whether abnormalities in amygdala function persist in long-term methamphetamine abstainers. Methods: In this study, 38 long-term male methamphetamine abstainers (>12 months) and 40 demographically matched male healthy controls (HCs) were recruited. Considering the heterogeneous nature of the amygdala structure and function, we chose 4 amygdala subregions (i.e., left lateral, left medial, right lateral, and right medial) as regions of interest (ROI) and compared the ROI-based resting-state functional connectivity (FC) at the whole-brain voxel-wise between the two groups. We explored the relationship between the detected abnormal connectivity, methamphetamine use factors, and the duration of withdrawal using correlation analyses. We also examined the effect of methamphetamine use factors, months of withdrawal, and sociodemographic data on detected abnormal connectivity through multiple linear regressions. Results: Compared with HCs, long-term methamphetamine abstainers showed significant hyperconnectivity between the left lateral amygdala and a continuous area extending to the left inferior/middle occipital gyrus and left middle/superior temporal gyrus. Abnormal connections negatively correlated with methamphetamine withdrawal time (r = -0.85, p < 0.001). The linear regression model further demonstrated that the months of withdrawal could identify the abnormal connectivity (βadj = -0.86, 95%CI: -1.06 to -0.65, p < 0.001). Discussion: The use of methamphetamine can impair the neural sensory system, including the visual and auditory systems, but this abnormal connectivity can gradually recover after prolonged withdrawal of methamphetamine. From a neuroimaging perspective, our results suggest that withdrawal is an effective treatment for methamphetamine.

Correlates of impulsivity among female sex workers in Mexico

Impulsivity is a trait characteristic that is associated with sexual risk behavior. We examined correlates of impulsivity among 602 female sex workers (FSWs) enrolled in a sexual risk reduction intervention in Mexico (2016-2020). Impulsivity was positively associated with condomless sex with clients. Higher levels of impulsivity were associated with greater use of alcohol and heavy drugs, use of illicit drugs with clients, sexual/physical abuse history, and clinical depression. Global public health policy that supports free substance abuse treatment in combination with psychotherapeutic treatments (e.g. regulation management skills) and behavioral-focused therapy may help to reduce HIV/STI incidence in this vulnerable population.

Behavioral Risk Factors for HIV Infection in Hospitalized Persons Who Co-use Stimulants and Opioids

We investigated the association of 90-day opioid and stimulant co-use and HIV risk behaviors in a cross-sectional analysis of hospitalized HIV-negative people who inject drugs (PWID). We compared those injecting opioids alone to two sub-groups who co-used opioids with (1) cocaine, (2) amphetamine-type stimulants (ATS), on sex and injection drug risk behaviors assessed via the Risk Assessment Battery (RAB), where a higher score indicates a higher risk. Of 197 participants who injected opioids, 53% co-used cocaine only, 5% co-used ATS only, 18% co-used both cocaine and ATS, 24% co-used neither stimulant. PWID who injected opioids alone had a mean RAB drug risk score of 5.98 points and sex risk score of 2.16 points. Compared to PWID who injected opioids alone, PWID who co-used stimulants had higher mean drug risk RAB scores: cocaine, b = 2.84 points [95% confidence interval (CI) 1.01; 4.67]; ATS, b = 3.43 points (95% CI 1.29; 5.57). Compared to PWID who injected opioids alone, cocaine co-use was associated with higher sex RAB scores b = 1.06 points (95% CI 0.32; 1.79). Overall, we found a significant association between stimulant co-use and higher HIV sex and drug risk scores.

Metacognition and Self-determination, Impulsivity and Emotional intelligence, and its relation with wellbeing and health indicators in young adults

Background: From the evidence, it is inferred the influence of cognitive or motivational variables over the emotional ones and from these on the perception and self-reported wellbeing and health, with direct implications for health promotion and prevention. Method: a quantitative approach, descriptive, correlational cross-sectional with statistical explanatory analysis investigation was conducted, analyzing the data through path modeling of the partial least squares approach of the structural equations model, by using the Smart PLS software 3.3.2 version, analyzing consequently the convergent and discriminant validity of the model. A total 223 undergraduate university young adult students was evaluated, 41 men (18,4%) and 182 women (81,6%) with ages between 18 and 30 years old (µ= 24,26 y σ=±3,30), from Bogotá Colombia participated. Results: The results allowed to significant relations between the self – determination with the impulsivity and emotional intelligence, and from these with the psychological well-being and healthy habits. There were not identified significant relations between the metacognition and the impulsivity, although there are between metacognition and emotional intelligence. Conclusions: The proposed model about the significant relations between metacognition and self-determination with impulsivity and emotional intelligence and between these and the psychological well-being and healthy habits was confirmed. The specific result related to the absence of significant relations between metacognition and the impulsivity suggest for futures research, to emphasize on the metacognitive process implicated on the emotional components. The results are discussed, its implications and the necessity to be considered more determinants for the promotion of health.

Dancing Improves Emotional Regulation in Women With Methamphetamine Use Disorder But Use of a Cycle Ergometer Does Not

Background

Emotional regulation is crucial to people who receive a diagnosis of methamphetamine (MA) use disorder. Although evidence that exercise improves emotional regulation is robust, little is known about whether exercise will improve emotional processing in women with MA use disorder.

Methods

In the present study, 36 women with MA use disorder aged 20 to 34 years and residing in the Drug Rehabilitation Bureau of Mogan Mountain in Zhejiang province were assigned to 1 of 2 exercise intervention groups-dancing or stationary cycling. Both types of exercise were performed at 65-75% of the maximum heart rate for 30 min. Immediately before and after the exercise bout, the participants were asked to score their feelings using a nine-point Likert scale as they viewed emotionally negative, positive, or neutral images in blocks of 20 images each, for a total of 60 images. Concurrent with viewing the images and self-rating their emotions, the women also underwent functional near-infrared spectroscopy to assess changes in brain activity.

Results

There were no significant differences in the demographic or MA use characteristics assessed for the women between the two exercise groups. We found main effect of image valence (F _2,33 = 69.61, p < 0.01), significant interaction effect of time and image valence was found (F _2,33 = 4.27, p < 0.05) and trend increase in the self-rated emotional scale score for viewing negative images in both groups after 30-min exercise intervention, and the dancing group presented more significant trends than cycling group. In addition, activation in the dorsolateral prefrontal cortex of dancers, but not of cyclists, while viewing negative images was significantly lower after vs. before dancing (F _2,33 = 5.43, p < 0.05). This result suggested that 30 min of dancing decreased neural activity in women with MA use disorder while they viewed negative images specifically in a brain region known to guide the selection of appropriate behaviors, and to shift attention.Taken together, the findings of this study suggest that for women with MA abuse disorder, 30 min of dancing, rather than of stationary cycling, may ameliorate negative emotional reactions by decreasing attention to negative stimuli.

Methamphetamine in Orthopaedics: Considerations of an At-Risk Population

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Methamphetamine use by orthopaedic trauma patients has risen to epidemic proportions.

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Perioperative methamphetamine use by orthopaedic trauma patients requires physicians to consider both medical and psychosocial factors during treatment.

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Behavioral and psychosocial effects of methamphetamine use present barriers to care.

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Patients who use methamphetamine face elevated rates of complications.

How is intolerance of uncertainty related to negative affect in individuals with substance use disorders? The role of the inability to control behaviors when experiencing emotional distress

We used structural equation modeling to assess the role of impaired emotional awareness and clarity (Impaired Awareness/Clarity) and inability to control behaviors when experiencing emotional distress (Inability to Control Behaviors) as an account for the relationship between intolerance of uncertainty (IU) and negative affect (NA) in individuals with Substance Use Disorders (SUDs) and healthy controls (HCs) used for comparison. One-hundred and thirty-one individuals with SUDs (42.75% female; mean age = 39.74 ± 11.83) and 131 sex-matched HCs (mean age = 40.02 ± 12.34) entered the study. Participants completed questionnaires assessing the constructs of interest. Single-group analyses aimed to identify a baseline model for each group and test the hypothesized direct/indirect relations' overall significance. Then, a multigroup analysis tested the invariance of model parameters between SUD and HC groups. The model in which IU had both direct and indirect relationships with NA through Impaired Awareness/Clarity and Inability to Control Behaviors was a good fit to the data. The indirect relationship of IU with NA through Inability to Control Behaviors was significant and moderate-sized. The relationship involving Impaired Awareness/Clarity and Inability to Control Behaviors was small-sized and significant in single group analysis only. The multigroup analysis supported the association of IU with NA through Inability to Control Behaviors in the SUD group. Overall, our study highlights the crucial role of the Inability to Control Behaviors in SUDs and suggests that its association with IU might fuel NA in this population.

Gender Moderates the Partial Mediation of Impulsivity in the Relationship Between Psychiatric Distress and Problematic Online Gaming: Online Survey

BACKGROUND

Research has shown that some individuals can develop problematic patterns of online gaming, leading to significant psychological and interpersonal problems. Psychiatric distress and impulsivity have been suggested to contribute to problematic online gaming (POG).

OBJECTIVE

This study aimed to investigate the potential mediating or moderating mechanisms of impulsivity and gender-related differences in possible associations between psychiatric distress and POG.

METHODS

A total of 596 matched female and male participants, ranging in age from 14 to 38 years (mean 21.4, SD 4.5), were chosen from a large cross-sectional, nationwide Hungarian online gaming sample. Participants completed online questionnaires about self-reported impulsivity, psychiatric distress, and POG.

RESULTS

Psychiatric distress directly predicted POG, and impulsivity partially mediated the relationship between psychiatric distress and POG. However, this mediation effect was found only for the impatience factor of impulsivity. Impulsivity did not moderate the relationship between psychiatric distress and POG. A moderating effect of gender was not found in the direct relationship between psychiatric distress and POG. However, a moderated mediation analysis revealed that impatience mediated the association between psychiatric distress and POG in males, whereas the indirect effect of impatience was not significant in females.

CONCLUSIONS

The results of this work highlight gender-related difference among online gamers in the mediation effect of impulsivity between psychiatric distress and POG and provide novel insights regarding clinical implications for preventing or treating POG.

Causes and Consequences of Drug Abuse: A Comparison Between Synthetic Drug and Heroin Users in Urban China

This article examined the differences in causes and health consequences between synthetic drug and heroin abuse in urban China. Two-group comparisons were conducted to quantify differences in individual characteristics, causes of drug use, and HIV/STI risky sexual behavior between synthetic drug and heroin users; logistic regressions were employed to assess the net effect of synthetic drug use on risky sexual behavior. Results revealed that causes of synthetic drug use differed from those of heroin use; a combination of the knowledge gap concerning the harmful impact of synthetic drugs and the lesser punishment for their use appeared a main reason behind the shift from heroin to synthetic drugs; and synthetic drug use was a significant and powerful risk factor for HIV/STI risky sexual behavior. Educational and behavioral interventions are urgently needed to prevent the initiation of synthetic drug use among users to reduce their HIV/STI risky sexual behavior.

Bias Toward Drug-Related Stimuli Is Affected by Loading Working Memory in Abstinent Ex-Methamphetamine Users

Background: There is a trade-off between drug-related impulsive process and cognitive reflective process among ex-drug abusers. The present study aimed to investigate the impulsive effects of methamphetamine-related stimuli on working memory (WM) performance by manipulating WM load in abstinent ex-methamphetamine users. Methods: Thirty abstinent ex-methamphetamine users and 30 nonaddict matched control participants were recruited in this study. We used a modified Sternberg task in which participants were instructed to memorize three different sets of methamphetamine-related and non-drug-related words (three, five, or seven words) while performing a secondary attention-demanding task as an interference. Results: Repeated-measures ANOVA revealed that reaction times of abstinent ex-methamphetamine users increased during low WM load (three words) compared to the control group (p = 0.01). No significant differences were observed during high WM loads (five or seven words) (both p's > 0.1). Besides, reaction times of the experimental group during trials with high interference (three, five, or seven words) were not significantly different compared to the control group (p > 0.2). Conclusion: These findings imply that increasing WM load may provide an efficient buffer against attentional capture by salient stimuli (i.e., methamphetamine-related words). This buffer might modify the effect of interference bias. Besides, presenting methamphetamine-related stimuli might facilitate the encoding phase due to bias toward task-relevant stimuli. This finding has an important implication, suggesting that performing concurrent demanding tasks may reduce the power of salient stimuli and thus improve the efficiency of emotional regulation strategies.

Developmental perspectives on methamphetamine abuse: Exploring adolescent vulnerabilities on brain and behavior

Most people that experience illicit drugs do so for the first time during adolescence, and methamphetamine (meth) is no exception. Therefore, research into the effects of meth should highlight the adolescent period. Despite this, the vast majority of current literature has mainly focused on meth exposure during adulthood. In this review, we first describe existing literature that compares the behavioral effects of meth where exposure occurs in adolescence compared to adulthood. Given that there are actually very few such studies, we also look at what is known about neural effects of meth in the adult brain, and relate these to normal neural development occurring during the adolescent period to establish how meth may target maturing regions and related neurochemistry. What emerges overall is that adolescents appear to be more vulnerable to the rewarding and reinforcing effects of meth, and that meth indeed has effects on areas that are in flux during adolescence. However, there is some evidence for a paradoxical resistance to the neurotoxic effects during this period. We highlight the need for further age-related research to better understand, treat, and prevent meth use disorders and addiction in general.

The relationship between impulsivity and methamphetamine use severity in a community sample

BACKGROUND

Abuse of psychostimulants, including methamphetamine (MA), has been linked to heightened impulsivity. While previous research has demonstrated differences in impulsivity between MA users and non-substance users, less is known about variability in impulsivity within MA users and whether the severity of MA use related problems predicts impulsivity within individuals who regularly use MA. This study aims to elucidate the relationship between impulsivity and MA use severity.

METHOD

Non-treatment seeking individuals who reported regular MA use (n = 177) completed an impulsivity battery comprising self-report and behavioral measures. A structural equation modeling (SEM) approach was used to test the relationship between the MA use related problem severity and measures of impulsivity.

RESULTS

The final SEM model of impulsivity and MA use related problems (CFI = 0.897, RMSEA = 0.059, S-B scaled χ2 [260,n = 103] = 406.86) revealed that greater MA use severity was associated with greater self-reported impulsiveness, but no relationship was found between MA use severity and behavioral measures of impulsivity.

CONCLUSIONS

The current findings extend previous research by providing additional evidence that MA use is associated with increased self-reported impulsivity and highlights the importance of evaluating impulsivity as a multidimensional construct.

Effects of methamphetamine abuse on spatial cognitive function

Methamphetamine (MA) abuse has been rising rapidly over the past decade, however, its impact in spatial cognitive function remains unknown. To understand its effect on visuospatial ability and spatial orientation ability, 40 MA users and 40 non-MA users conducted the Simple Reaction Task (Task 1), the Spatial Orientation Task (Task 2), and the Mental Rotation Task (Task 3), respectively. There was no significant difference in either accuracy or reaction time (RT) between 2 groups in Task 1. During Task 2, in comparison with non-MA users, MA users performed poorer on RT, but not in accuracy for foot and hand stimuli. In addition, both non-MA and MA users responded much more quickly to upward stimuli than downward stimuli on vertical surface, however, only non-MA users exhibited leftward visual field advantage in horizontal orientation processing. As for Task 3, MA users exhibited poorer performance and more errors than their healthy counterparts. For each group, linear relationship was revealed between RT and orientation angle, whereas MA abuse led to longer intercept for all stimuli involved. Our findings suggested that MA abuse may lead to a general deficit in the visuospatial ability and the spatial orientation ability with more serious impact in the former.

Epidemiological Characteristics and Risk Factors of Methamphetamine-Associated Psychotic Symptoms

Objective: To explore the epidemiological characteristics and the risk factors for methamphetamine (MA)-associated psychotic symptoms among MA users in China. Methods: A cross-sectional study was conducted between April, 2012 and October, 2015 among individuals for whom MA was the principal drug of use in a Compulsory Drug Detoxification Center in Beijing, Guangdong Province. Demographic, drug use and psychological characteristics were examined using a specifically-designed questionnaire, the Positive and Negative Syndrome Scale, Barratt Impulsive Scale, Hamilton Anxiety Scale and Beck Depression Inventory. Logistic regression was performed to explore the risk factors for MA-associated psychotic symptoms. Results: A total of 1685 participants were included. Participants were predominantly aged 30 or above, unemployed, and were unmarried Han Chinese men, with limited education. The duration of MA use was more than 3 months in 72.3%. 47.8% reported that the dose of MA use was ≥ 0.2 g per occasion of use. 11.5% had used two or more synthetic drugs. The prevalence of MA-associated psychotic symptoms was 17.0% among MA users during periods of abstinence. Multiple logistic regression analyses showed that a higher dose (≥0.2 g per time), a longer duration of MA use (>3 months) a history of heroin use and a history of tobacco use were associated with MA-associated psychotic symptoms, with adjusted odds ratios (ORs) of 1.96 (95% confidence interval [CI]: 1.40-2.76), 1.98 (95% CI: 1.33-2.96) and 2.45 (95% CI: 1.67-3.60), 1.78 (95% CI: 1.27-2.49) respectively. MA-associated psychotic symptoms were less common among married/cohabitating than unmarried (OR = 0.56; 95% CI: 0.39-0.81), and unemployed than employed (OR = 0.65; 95% CI: 0.47-0.92) individuals. MA users with anxiety and depression symptoms had significantly greater risk for MA-associated psychotic symptoms by 9.70 (6.92-13.59) and 1.90 (1.36-2.65) times respectively. Individuals with higher impulsivity were more likely to have MA-associated psychotic symptoms than those with lower (OR = 2.19; CI:1.50-3.20). Conclusion: MA-associated psychotic symptoms occurred frequently among MA users in China. The efforts that facilitate drug users' attempts to reduce MA use, abstain from poly-drug use, and control associated psychiatric symptoms and impulsivity should be supported because of their potential contribution to MA-associated psychotic symptoms in this population.

Prevalence Rates of Personality Disorder and Its Association With Methamphetamine Dependence in Compulsory Treatment Facilities in China

Methamphetamine use is popular and rapidly increasing in China, and the co-occurrence of personality disorders has an impact on treatment outcomes and may increase vulnerability of developing dependence. The aim of the present study was to investigate the prevalence rates of personality disorders in methamphetamine users and further explore the association between personality disorders and methamphetamine use status. Five hundred and seventy-seven male methamphetamine users were recruited. The self-developed questionnaire was used for demographics, and a Structural Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) (SCID-I/II) was performed covering psychiatric diagnosis. Our study found the prevalence of antisocial personality disorder in male methamphetamine users was 71.4%, followed by borderline (20.2%) and obsessive-compulsive (17.9%) personality disorder. Borderline and antisocial personality disorders were found to be risk factors of methamphetamine dependence (adjusted odds ratio = 2.891, p = 0.007 and adjusted odds ratio = 1.680, p = 0.042). These findings suggested personality disorders were highly prevalent in male methamphetamine users, and the comorbidity of antisocial and borderline personality disorders are especially associated with methamphetamine dependence.

Sex Differences in the Association Between Internalizing Symptoms and Craving in Methamphetamine Users

OBJECTIVES

Methamphetamine (MA) users often have substantial psychiatric comorbidities, with nearly a third reporting lifetime mood disorders and over a quarter reporting lifetime anxiety disorders. Female MA users are more likely to endorse depression and anxiety symptoms compared with men. Craving has been related to mood/anxiety symptoms in MA users. To extend the literature on sex differences in MA use disorder, the present study examines the role of sex as a moderator of the relationship between mood/anxiety symptoms and MA craving.

METHODS

Participants (N = 203) were nontreatment-seeking, current MA users, recruited from the Los Angeles community for enrollment in a larger pharmacotherapy trial. At the assessment visit, participants completed multiple measures including the Methamphetamine Urge Questionnaire, the Beck Depression Inventory, and the Beck Anxiety Inventory.

RESULTS

The relationship between depression symptomatology and MA craving was moderated by sex (F = 6.18, P = 0.01), such that the relationship was positive and significant for men (P < 0.001), but was not significant for women. Similarly, sex significantly moderated the relationship between anxiety and MA craving (F = 5.99, P = 0.02), such that the relationship was also positive and significant in men, but not in women (P < 0.001).

CONCLUSIONS

These results suggest that men may be more sensitive to the effects of internalizing symptoms on MA craving than women. Given craving's propensity to predict relapse, these initial findings indicate the necessity of treating comorbid psychiatric problems in male MA users, which may in turn assist in the attenuation of craving.

Violent offences of methamphetamine users and dilemmas of forensic psychiatric assessment

Methamphetamine (MA), an extremely addictive synthetic stimulant, has quickly spread to become the most frequently used illicit drug in China. People with a history of chronic and heavy MA use have a high possibility of exhibiting schizophrenia-like psychotic symptoms, mainly delusions of reference, auditory hallucinations and cognitive deficits. These emerging findings suggest MA use increases aggression and violence and that there is a correlation between MA use and violence. However, it is unclear how to assess the capacity of criminal responsibility in "MA-induced" psychosis and how to set clear boundaries between schizophrenia and MA-induced psychosis when only limited and inconsistent evidence is available. Furthermore, a final persuasive differential diagnostic method based on improved understanding of schizophrenia and MA-induced psychotic disorders has yet to be developed. This paper will evaluate the epidemiology, social harm, and forensic psychiatric assessment of MA users, propose a future direction for the differential diagnosis between MA-induced psychotic disorders and schizophrenia, and put forward some practical solutions to assess the capacity of criminal responsibility of defendants with drug-induced psychotic disorder.

Brain Microstructure and Impulsivity Differ between Current and Past Methamphetamine Users

Methamphetamine (Meth) use disorder continues to be highly prevalent worldwide. Meth users have higher impulsivity and brain abnormalities that may be different between current and past Meth users. The current study assessed impulsivity and depressive symptoms in 94 participants (27 current Meth users, 32 past Meth users and 35 non-drug user controls). Additionally, brain microstructure was assessed using diffusion tensor imaging (DTI); fractional anisotropy (FA) and mean diffusivity (MD) were assessed in the striatum, and FA, MD, radial and axial diffusivity were quantified in five white matter structures using DtiStudio.Across the three subject groups, current users had the highest self-reported impulsivity scores, while both Meth user groups had larger striatal structures than the controls. Past Meth users had the highest FA and lowest MD in the striatum, which is likely due to greater magnetic susceptibility from higher iron content and greater dendritic spine density. In white matter tracts, current Meth users had higher AD than past users, indicating greater water diffusion along the axons, and suggesting inflammation with axonal swelling. In contrast, past users had the lowest AD, indicating more restricted diffusion, which might have resulted from reactive gliosis. Although current Meth users had greater impulsivity than past users, the brain microstructural abnormalities showed differences that may reflect different stages of neuroinflammation or iron-induced neurodegeneration. Combining current and past Meth users may lead to greater variability in studies of Meth users. Longitudinal studies are needed to further evaluate the relationship between recency of Meth use and brain microstructure.

Sex differences in impulsivity and brain morphometry in methamphetamine users

Methamphetamine (METH) is an addictive stimulant, and METH users have abnormal brain structures and function. The aims of this study were to investigate the relationships between impulsivity, brain structures, and possible sex-specific differences between METH users and non-drug using Controls. Structural MRI and the Barratt Impulsiveness Scale (BIS) questionnaire were completed in 124 subjects: 62 METH (ages 41.2 ± 1.4 years, 34 males) and 62 Controls (ages 43.3 ± 2.3 years, 36 males). Independent and interactive effects of METH use status and sex were evaluated. Relationships between METH usage characteristics, brain morphometry, and impulsivity scores were examined. METH users had higher impulsivity scores, on both the Cognitive and Behavioral Factors from the BIS (p < 0.0001-0.0001). Compared with same-sex Controls, male METH users had larger, while female METH users had smaller, right superior frontal cortex (interaction-p = 0.0005). The male METH users with larger frontal volumes and female METH users with smaller or thinner frontal cortices had greater Cognitive impulsivity (interaction-p ≤ 0.05). Only female METH users showed relatively larger nucleus accumbens (interaction-p = 0.03). Greater impulsivity and thinner frontal cortices in METH users are validated. Larger superior frontal cortex in male METH users with greater cognitive impulsivity suggest decreased dendritic pruning during adolescence might have contributed to their impulsive and drug use behaviors. In the female METH users, smaller frontal cortices and the associated greater impulsivity suggest greater neurotoxicity to these brain regions, while their relatively larger nucleus accumbens suggest an estrogen-mediated neuroprotective glial response. Men and women may be affected differently by METH use.

White matter microstructure and impulsivity in methamphetamine dependence with and without a history of psychosis

BACKGROUND

Methamphetamine (MA) use may lead to white matter injury and to a range of behavioral problems and psychiatric disorders, including psychosis. The present study sought to assess white matter microstructural impairment as well as impulsive behavior in MA dependence and MA-associated psychosis (MAP).

METHODS

Thirty patients with a history of MAP, 39 participants with MA dependence and 40 healthy controls underwent diffusion tensor imaging (DTI). Participants also completed the UPPS-P impulsive behavior questionnaire. We applied tract-based spatial statistics (TBSS) to investigate group differences in mean diffusivity (MD), fractional anisotropy (FA), axial (λ‖ ) and radial diffusivity (λ⊥ ), and their association with impulsivity scores and psychotic symptoms.

RESULTS

The MAP group displayed widespread higher MD, λ‖ and λ⊥ levels compared to both controls and the MA group, and lower FA in extensive white matter areas relative to controls. MD levels correlated positively with negative psychotic symptoms in MAP. No significant DTI group differences were found between the MA group and controls. Both clinical groups showed high levels of impulsivity, and this dysfunction was associated with DTI measures in frontal white matter tracts.

CONCLUSIONS

MAP patients show distinct patterns of impaired white matter integrity of global nature relative to controls and the MA group. Future work to investigate the precise nature and timing of alterations in MAP is needed. The results are further suggestive of frontal white matter pathology playing a role in impulsivity in MA dependence and MAP. Hum Brain Mapp 37:2055-2067, 2016. © 2016 Wiley Periodicals, Inc.

Everyday problems with executive dysfunction and impulsivity in adults recovering from methamphetamine addiction

OBJECTIVES

Compared with non-addicted controls (CTLs), adults in remission from methamphetamine addiction (MA-REM) evidence impairments on objective measures of executive functioning and impulsivity.

METHODS

To evaluate the impact of these impairments in MA-REM adults, demographically matched groups (MA-REM, n=30; CTLs, n=24) completed objective and self-report measures of executive functioning and impulsivity.

RESULTS

MA-REM adults demonstrated significantly (p < 0.050) greater objective and subjective problems with executive functioning and impulsivity.

CONCLUSIONS

These results suggest that adults in MA-REM are aware of their deficits and that these deficits have significant impact in everyday life.

The impact of age, HIV serostatus and seroconversion on methamphetamine use

BACKGROUND

Characterizing methamphetamine use in relation to age, HIV serostatus and seroconversion is pertinent given the increasingly older age of the population with HIV and the intertwined epidemics of methamphetamine use and HIV.

OBJECTIVES

Study aims were to investigate whether (i) methamphetamine use differs by age and HIV serostatus, and (ii) receiving an HIV diagnosis impacts methamphetamine use among younger and older persons with HIV.

METHODS

This study examined methamphetamine use characteristics among 217 individuals with a lifetime methamphetamine dependence diagnosis who completed an in-person study assessment.

RESULTS

Multivariable regressions revealed that HIV serostatus uniquely attenuates methamphetamine use, such that persons with HIV report a smaller cumulative quantity (β = -0.16, p = 0.01) and a fewer number of days (β = -0.18, p = 0.004) of methamphetamine use than persons without HIV. Among the HIV+ sample, all participants persisted in methamphetamine use after receiving an HIV diagnosis, with about 20% initiating use after seroconversion. Repeated measures analysis of variance indicated that density of methamphetamine use (i.e. grams per day used) was greater among the younger, relative to the older, HIV+ group (p = 0.02), and increased for both age groups following seroconversion (p < 0.001).

CONCLUSION

These analyses indicate that although HIV serostatus may attenuate methamphetamine use behaviors, many people with HIV initiate, or persist in, methamphetamine use after receiving an HIV diagnosis. These findings raise the question of whether tailoring of prevention and intervention strategies might reduce the impact of methamphetamine and HIV across the age continuum.

Impulsivity in abstinent alcohol and polydrug dependence: a multidimensional approach

RATIONALE

Dependence on drugs and alcohol is associated with impaired impulse control, but deficits are rarely compared across individuals dependent on different substances using several measures within a single study.

OBJECTIVES

We investigated impulsivity in abstinent substance-dependent individuals (AbD) using three complementary techniques: self-report, neuropsychological and neuroimaging. We hypothesised that AbDs would show increased impulsivity across modalities, and that this would depend on length of abstinence.

METHODS

Data were collected from the ICCAM study: 57 control and 86 AbDs, comprising a group with a history of dependence on alcohol only (n = 27) and a group with history of dependence on multiple substances ("polydrug", n = 59). All participants completed self-report measures of impulsivity: Barratt Impulsiveness Scale, UPPS Impulsive Behaviour Scale, Behaviour Inhibition/Activation System and Obsessive-Compulsive Inventory. They also performed three behavioural tasks: Stop Signal, Intra-Extra Dimensional Set-Shift and Kirby Delay Discounting; and completed a Go/NoGo task during fMRI.

RESULTS

AbDs scored significantly higher than controls on self-report measures, but alcohol and polydrug dependent groups did not differ significantly from each other. Polydrug participants had significantly higher discounting scores than both controls and alcohol participants. There were no group differences on the other behavioural measures or on the fMRI measure.

CONCLUSIONS

The results suggest that the current set of self-report measures of impulsivity is more sensitive in abstinent individuals than the behavioural or fMRI measures of neuronal activity. This highlights the importance of developing behavioural measures to assess different, more relevant, aspects of impulsivity alongside corresponding cognitive challenges for fMRI.

Social functioning and internalized stigma in individuals diagnosed with substance use disorder

The aim of this descriptive study was to determine social functioning and internalized stigma in individuals with substance use disorder. The study sample consisted of 105 patients diagnosed with substance use disorder according to the DSM-IV-TR diagnostic criteria. A Descriptive Information Form, Internalized Stigma of Mental Illness Scale (ISMI) and Social Functioning Scale (SFS) were used for data collection. Average total SFS score of the patients was 103.25±25.09 points, indicating an intermediate level of social functioning. Average total ISMI score of patients was 2.92±0.48 points, reflecting a high level of internalized stigma. A negative significant association was observed between the internalized stigma levels and social functioning of patients. These results suggest that rehabilitation of substance users should include counseling services in order to reduce internal perception of stigma and improve their social functioning.

Surgical Intervention for Penile Methamphetamine Injections

Methamphetamine is a central nervous system stimulant and is the second most commonly used illicit drug after cannabis. Methamphetamine use for sexual pleasure is well documented. In this case report, we describe two cases presenting to our urban county hospital associated with complications related to penile injection of methamphetamine. Both patients developed penile abscesses and required urgent surgical incision and drainage. Penile abscesses represent a rare complication associated with IV drug administration into the penile corpora. Resultant penile abscesses require broad-spectrum antibiotics and surgical drainage. Further understanding of methamphetamine abuse along with the role it plays in sexual enhancement would be an invaluable addition to understanding of the rationale behind this self-administered stimulant. Drainage of penile abscesses associated with IV drug users may be hazardous to healthcare providers who are at risk from a needle stick injury.

Relationship of impulsivity and depression during early methamphetamine withdrawal in Han Chinese population

OBJECTIVE

High level of impulsivity as well as depression is thought to be involved in the maintenance and development of methamphetamine (METH) addiction. However, the relationship between impulsivity and depression has not been studied thoroughly in METH dependence subjects, especially in early METH abstinent subjects. In this study, our objective is to explore the interplay between the depressive symptoms and impulsivity in early METH abstinent subjects.

METHODS

A total of 182 early abstinent METH dependent subjects (abstinence for 1-7 days) were recruited and the level of impulsivity was measured by the Barratt Impulsiveness Scale (BIS-11). Depressive symptoms and anxiety symptoms were assessed by the short 13-item Beck Depression Inventory (BDI-13) and Beck Anxiety Inventory (BAI) respectively.

RESULTS

Global impulsivity of BIS-11 was significantly correlated with depressive symptoms among early METH abstinent subjects (r=0.283, p=0.001). Moreover, all subscales of BIS-11 were also found to be correlated with depressive symptoms: correlation with attentional impulsivity (r=0.202, p=0.006); correlation with motor impulsivity (r=0.267, p=0.001); and correlation with non-planning impulsivity (r=0.177, p=0.017).

CONCLUSIONS

This study showed a relationship between impulsivity and depression, which may further the comprehension of motivational elements contributing to the maintenance and development of METH use disorder. Future research would be dedicated to exploring underlying mechanisms of association between impulsivity and depression.

Neuropsychological Consequences of Chronic Drug Use: Relevance to Treatment Approaches

Heavy use of drugs impacts of the daily activities of individuals in these activities. Several groups of investigators have indeed documented changes in cognitive performance by individuals who have a long history of chronic drug use. In the case of marijuana, a wealth of information suggests that heavy long-term use of the drug may have neurobehavioral consequences in some individuals. In humans, heavy cocaine use is accompanied by neuropathological changes that might serve as substrates for cognitive dysfunctions. Similarly, methamphetamine users suffer from cognitive abnormalities that may be consequent to alterations in structures and functions. Here, we detail the evidence for these neuropsychological consequences. The review suggests that improving the care of our patients will necessarily depend on the better characterization of drug-induced cognitive phenotypes because they might inform the development of better pharmacological and behavioral interventions, with the goal of improving cognitive functions in these subsets of drug users.

"When you get old like this … you don't run those risks anymore": influence of age on sexual risk behaviors and condom use attitudes among methamphetamine-using heterosexual women with a history of partner violence

BACKGROUND

Drug use and partner violence affect older women, yet few studies highlight age-specific HIV risks and prevention strategies. This study compares sexual risk behaviors, condom use attitudes, and HIV knowledge between midlife/older women (ages 45+) and younger women (ages 18-44) reporting methamphetamine use and partner violence in San Diego, California.

METHODS

Our mixed methods study used themes from a qualitative substudy (n = 18) to inform logistic regression analysis of baseline data from an HIV behavioral intervention trial (n = 154).

FINDINGS

Age-related qualitative themes included physiologic determinants, HIV knowledge, and "dodging the bullet," referring to a lifetime of uncertainty surrounding HIV serostatus after engaging in unsafe drug and sex practices. Midlife/older age was associated with never being married (24.2% vs. 51.2; p = .03), having less than a high school education/GED (12.1% vs. 34.7%; p = .04), lower condom use self-efficacy (2.87 vs. 3.19; p = .03), lower positive outcome expectancies (1.9 vs. 2.1; p = .04), and lower HIV knowledge (85.3% vs. 89.7%; p = .04); however, sexual risk behaviors were not associated with age group. In the multivariate analysis, midlife/older age remained independently associated with lower condom use self-efficacy (adjusted odds ratio, 0.49; 95% CI, 0.27-0.87) and lower HIV knowledge (adjusted odds ratio, 0.96; 95% CI, 0.93-0.99).

CONCLUSIONS

Midlife/older methamphetamine-using women with experiences of partner violence present similar sexual risk profiles, but possess different HIV-related knowledge and attitudes toward prevention methods compared with their younger counterparts. Clinicians and public health practitioners can have a positive impact on this overlooked population by assessing HIV risks during routine screenings, encouraging HIV testing, and providing age-appropriate HIV prevention education.

"Frontal systems" behaviors in comorbid human immunodeficiency virus infection and methamphetamine dependency

Human immunodeficiency virus (HIV) infection and methamphetamine (MA) dependence are associated with neural injury preferentially involving frontostriatal circuits. Little is known, however, about how these commonly comorbid conditions impact behavioral presentations typically associated with frontal systems dysfunction. Our sample comprised 47 HIV-uninfected/MA-nondependent; 25 HIV-uninfected/MA-dependent; 36 HIV-infected/MA-nondependent; and 28 HIV-infected/MA-dependent subjects. Participants completed self-report measures of "frontal systems" behaviors, including impulsivity/disinhibition, sensation-seeking, and apathy. They also underwent comprehensive neurocognitive and neuropsychiatric assessments that allowed for detailed characterization of neurocognitive deficits and comorbid/premorbid conditions, including lifetime Mood and Substance Use Disorders, Attention-Deficit/Hyperactivity Disorder, and Antisocial Personality Disorder. Multivariable regression models adjusting for potential confounds (i.e., demographics and comorbid/premorbid conditions) showed that MA dependence was independently associated with increased impulsivity/disinhibition, sensation-seeking and apathy, and HIV infection with greater apathy. However, we did not see synergistic/additive effects of HIV and MA on frontal systems behaviors. Global neurocognitive impairment was relatively independent of the frontal systems behaviors, which is consistent with the view that these constructs may have relatively separable biopsychosocial underpinnings. Future research should explore whether both neurocognitive impairment and frontal systems behaviors may independently contribute to everyday functioning outcomes relevant to HIV and MA.

The impact of methamphetamine ("tik") on a peri-urban community in Cape Town, South Africa

BACKGROUND

Over the last decade, South Africa's Western Cape has experienced a dramatic increase in methamphetamine ("tik") use. Our study explored local impressions of the impact of tik use in a peri-urban township community in Cape Town, South Africa.

METHODS

We conducted individual in-depth interviews with 55 women and 37 men who were regular attendees of alcohol-serving venues. Interviews were recorded and transcribed. A content analysis approach was used to identify themes related to the impact of tik use based on levels of the socio-ecological framework (individual, inter-personal and community).

RESULTS

Tik use was reported to be a greater issue among Coloureds, compared to Blacks. At an individual level, respondents reported that tik use had adverse effects on mental, physical, and economic well-being, and limited future opportunities through school drop-out and incarceration. At an inter-personal level, respondents reported that tik use contributed to physical and sexual violence as well as increased rates of sexual risk behaviour, particularly through transactional sex relationships. Respondents described how tik use led to household conflict, and had negative impacts on children, including neglect and poor birth outcomes. At a community level, respondents linked tik use to increased rates of crime, violence and corruption, which undercut community cohesion.

CONCLUSIONS

Our results highlight the negative impact that tik is having on individuals, households and the overall community in a peri-urban setting in South Africa. There is a clear need for interventions to prevent tik use in South Africa and to mitigate and address the impact of tik on multiple levels.

Relationship of age to impulsivity and decision making: a baseline secondary analysis of a behavioral treatment study in stimulant use disorders

Because stimulant use disorders remain prevalent across the lifespan, cognition is an important area of clinical care and research focus among aging adults with stimulant use disorders. This secondary analysis of a National Institute on Drug Abuse Clinical Trials Network study suggests that decision making, verbal learning/memory, executive function, and set shifting are important cognitive domains to screen clinically and treat in aging adults with stimulant use disorders. Some suggestions are made on how clinical treatment providers can practically use these results. An important direction for future research is the development of cognitively remediating treatments for impaired cognitive domains in aging adults with stimulant use disorders.

Behavioral endophenotypes of drug addiction: Etiological insights from neuroimaging studies

This article reviews recent advances in the elucidation of neurobehavioral endophenotypes associated with drug addiction made possible by the translational neuroimaging techniques magnetic resonance imaging (MRI) and positron emission tomography (PET). Increasingly, these non-invasive imaging approaches have been the catalyst for advancing our understanding of the etiology of drug addiction as a brain disorder involving complex interactions between pre-disposing behavioral traits, environmental influences and neural perturbations arising from the chronic abuse of licit and illicit drugs. In this article we discuss the causal role of trait markers associated with impulsivity and novelty-/sensation-seeking in speeding the development of compulsive drug administration and in facilitating relapse. We also discuss the striking convergence of imaging findings from these behavioural traits and addiction in rats, monkeys and humans with a focus on biomarkers of dopamine neurotransmission, and highlight areas where further research is needed to disambiguate underlying causal mechanisms. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.

Amphetamine-induced psychosis--a separate diagnostic entity or primary psychosis triggered in the vulnerable?

Use of amphetamine and methamphetamine is widespread in the general population and common among patients with psychiatric disorders. Amphetamines may induce symptoms of psychosis very similar to those of acute schizophrenia spectrum psychosis. This has been an argument for using amphetamine-induced psychosis as a model for primary psychotic disorders. To distinguish the two types of psychosis on the basis of acute symptoms is difficult. However, acute psychosis induced by amphetamines seems to have a faster recovery and appears to resolve more completely compared to schizophrenic psychosis. The increased vulnerability for acute amphetamine induced psychosis seen among those with schizophrenia, schizotypal personality and, to a certain degree other psychiatric disorders, is also shared by non-psychiatric individuals who previously have experienced amphetamine-induced psychosis. Schizophrenia spectrum disorder and amphetamine-induced psychosis are further linked together by the finding of several susceptibility genes common to both conditions. These genes probably lower the threshold for becoming psychotic and increase the risk for a poorer clinical course of the disease.The complex relationship between amphetamine use and psychosis has received much attention but is still not adequately explored. Our paper reviews the literature in this field and proposes a stress-vulnerability model for understanding the relationship between amphetamine use and psychosis.

High-risk situations related to relapse of methamphetamine use among Taiwanese adolescents: an instrumentation study

Methamphetamine is the leading illicit substance used by adolescents in Taiwan and the rise of its production and use is a major public health concern in Southeast and East Asia. The purpose of this study was to develop and test a new instrument to identify high-risk situations related to methamphetamine relapse among incarcerated Taiwanese adolescents. Participants in this study were arrested for methamphetamine use and mandatorily held at an abstinence center. In the instrument development phase, an item pool was generated from a qualitative study and further revised based on content evaluations by 6 clinical content experts. In the instrument analysis phase, the new tool was psychometrically tested. The intra-class correlation coefficient showed high stability of the instrument (r = .92). Factor analysis resulted in a 6-factor solution accounting for 66.68% of the variance in the 16-item model. Although this instrument was developed for use with Taiwanese adolescents, it needs further testing to confirm its usefulness in other cultural groups. The identified risky situations provide a beginning assessment tool that is easy to administer and can be used to identify teens at particular risk for relapse before being released from incarceration or other mandatory treatment programs. More research is needed to target specific and culturally determined triggers that can improve the validity of this tool for non Asian adolescents at risk for methamphetamine relapse.

Partner violence perpetration and victimization and HIV risk behaviors in St. Petersburg, Russia

Whether intimate partner violence (IPV) perpetration and victimization are associated with human immunodeficiency virus (HIV) risk behaviors is seldom investigated in Russia. The present study hypothesized that patients from a sexually transmitted infection center in Russia who perpetrated IPV or were victims of IPV would be more likely to have HIV risk behaviors including injection drug use, multiple partners, and inconsistent condom use than those who were not involved with IPV. We used a self-administered questionnaire to collect information from 381 patients on demographics, health status, injection drug use, sexual behaviors, and violence involving sexual partners between 2008 and 2009. After including sociodemographics, lifetime IPV perpetration was significantly associated with having had multiple sexual partners among male patients (odds ratio [OR] = 2.61, p < .05). IPV victimization was significantly associated with injection drug use among male and female patients (OR = 5.22, p < .05) and with inconsistent condom use among female patients (OR = 8.93, p < .05). IPV perpetration and victimization were common among male and female study participants and were associated with greater HIV risk behaviors. HIV prevention programs in Russia should address the risks associated with IPV among people at risk for HIV.

Visual Memory in Methamphetamine Dependent Individuals: Deficient Strategic Control of Encoding and Retrieval

OBJECTIVE

Chronic use of methamphetamine (MA) has moderate effects on neurocognitive functions associated with frontal systems, including the executive aspects of verbal episodic memory. Extending this literature, the current study examined the effects of MA on visual episodic memory with the hypothesis that a profile of deficient strategic encoding and retrieval processes would be revealed for visuospatial information (i.e., simple geometric designs), including possible differential effects on source versus item recall.

METHOD

The sample comprised 114 MA-dependent (MA+) and 110 demographically-matched MA-nondependent comparison participants (MA-) who completed the Brief Visuospatial Memory Test-Revised (BVMT-R), which was scored for standard learning and memory indices, as well as novel item (i.e., figure) and source (i.e., location) memory indices.

RESULTS

Results revealed a profile of impaired immediate and delayed free recall (p<0.05) in the context of preserved learning slope, retention, and recognition discriminability in the MA+ group. The MA+ group also performed more poorly than MA- participants on Item visual memory (p<0.05) but not Source visual memory (p>0.05), and no group by task-type interaction was observed (p>0.05). Item visual memory demonstrated significant associations with executive dysfunction, deficits in working memory, and shorter length of abstinence from MA use (p<0.05).

CONCLUSIONS

These visual memory findings are commensurate with studies reporting deficient strategic verbal encoding and retrieval in MA users that are posited to reflect the vulnerability of frontostriatal circuits to the neurotoxic effects of MA. Potential clinical implications of these visual memory deficits are discussed.

Personality and alcohol use: the role of impulsivity

Research has shown that personality traits associated with impulsivity influence alcohol use during emerging adulthood, yet relatively few studies have examined how distinct facets of impulsivity are associated with alcohol use and abuse. We examine the influence of impulsivity traits on four patterns of alcohol use including frequency of alcohol use, alcohol-related problems, binge drinking, and alcohol use disorders (AUDs) in a community sample of young individuals (N=190). In multivariate regression analyses that controlled for peer and parental alcohol use, psychological distress, and developmental correlates (i.e., college, marriage, employment) in emerging adulthood, we found that urgency and sensation seeking were consistently related to all four constructs of alcohol use. The present study suggests that distinct impulsivity traits may play different roles in escalation of alcohol use and development of AUDs during emerging adulthood.

Elevated neurobehavioral symptoms are associated with everyday functioning problems in chronic methamphetamine users

Chronic methamphetamine (MA) use is commonly associated with neural injury and neurocognitive deficits. The authors examined the nature and correlates of self-reported neurobehavioral symptoms (e.g., apathy, disinhibition, and executive dysfunction) in 73 individuals with histories of MA dependence (MA+) and 85 comparison participants with comparable demographics and risk histories. MA+ individuals endorsed significantly more severe neurobehavioral symptoms on the Frontal Systems Behavioral Scale, especially those of disinhibition and executive dysfunction. Elevations in neurobehavioral symptoms were independent of common comorbidities, including hepatitis C infection, attention-deficit/hyperactivity disorder (ADHD), mood disorders, and other substance-use factors. Notably, the severity of neurobehavioral symptoms was uniquely associated with self-reported decrements in instrumental activities of daily living in the MA-dependent sample. Findings indicate that chronic MA users may experience elevated neurobehavioral symptoms of disinhibition and executive dysfunction, potentially increasing their risk of functional declines.

Quality of life among treatment seeking methamphetamine-dependent individuals

As the number of men and women entering treatment for substance use disorders continues to increase across the country, it becomes vitally important to understand their quality of life (QOL) or perceived health status, in order to inform treatment efforts for improving such outcomes. To date, QOL assessments among methamphetamine (MA) dependent users are limited. This paper examines QOL health status among a sample of 838 treatment seeking MA users at admission. Using regression analysis, predictors of QOL are examined among MA users. Predictors of poor QOL among MA users at treatment admission included being female, white, high school educated or more, married, experiencing psychosocial dysfunction (lifetime trauma, suicide, social conflict), reporting a high frequency of both MA and polydrugs for 15 days or more in the past month, chronicity of MA and polydrug use, injection use, and having co-morbid medical and psychiatric impairment. Employment status was the only factor related to better health status perceptions. This study expands the scope of scholarly examination of MA-dependent users entering treatment, as there has not been a development of coherent profiles of QOL among representative samples of clinical MA-abusing populations to date.

The relationship between impulsivity and craving in cocaine- and methamphetamine-dependent volunteers

Impulsivity and craving have been independently hypothesized to contribute to sustained drug use and relapse in addiction. The primary focus of this project was to determine the relationship between impulsivity and craving in 85 cocaine-dependent and 73 methamphetamine-dependent, non-treatment-seeking volunteers. Drug use was assessed with a 14-item, self-report drug and alcohol use questionnaire. Self report instruments utilized included the Barratt Impulsivity Scale (BIS) and the Visual Analog Scale (VAS), which probed "just before your last use of cocaine (for cocaine-dependent participants) or methamphetamine (for methamphetamine-dependent participants), how much craving did you experience?" The groups were similar with respect to recent use of cocaine or methamphetamine, alcohol, nicotine, and marijuana. Analysis of variance (ANOVA) did not reveal significant differences between cocaine and methamphetamine groups for total impulsivity or total craving. Simple linear regression revealed correlations between total impulsivity and total craving in cocaine (r(2)=0.05, p≤0.03) and methamphetamine users (r(2)=0.09, p≤0.008). Participants were separated into high impulsivity (HIBIS) or low impulsivity (LOBIS) subgroups using a median split. ANOVA revealed significantly higher craving in the HIBIS group versus the LOBIS group in methamphetamine users (p≤0.02), but not in cocaine users. For both cocaine and methamphetamine groups, level of impulsivity and craving were found to be related to some drug use variables including years of alcohol use, severity of withdrawal, and craving level following drug use. Taken together, this study shows a marginal relationship between impulsivity and craving, which may further the understanding of motivational factors contributing to ongoing drug use and addiction in psychostimulant users.

Khat use and neurobehavioral functions: suggestions for future studies

Although there is a rich body of research available regarding the effect of acute and chronic khat dosing in animal models, research on the behavioral and cognitive effects of khat in human subjects is not extensive and several of the available studies have been done only in the context of observational and single-case studies. In light of the absence of a substantial literature on the neurobehavioral deficits associated with khat use and to provide a context that could be used to identify themes for future research we review previous research that has focused on other stimulant drugs. This review highlights multiple areas of neurocognitive deficit that have been identified in previous studies of individuals who have been chronic users of stimulants, such as amphetamines and methamphetamines. The review highlights a substantial body of evidence demonstrating a wide range of learning and memory impairments including deficits that persist during abstinence from active drug use. This review does not imply a similar khat effect, but due to some similarities pharmacologically between the active components of khat (cathinone and cathine) and amphetamines, future studies examining these same domains of cognitive functioning in chronic khat users and abstinent khat users appears to be warranted, if possible using some of the same or similar laboratory measures.