Subtypes in addiction and their neurobehavioral profiles across three functional domains

Rates of return to use in addiction treatment remain high. We argue that the development of improved treatment options will require advanced understanding of individual heterogeneity in Substance Use Disorders (SUDs). We hypothesized that considerable individual differences exist in the three functional domains underlying addiction-approach-related behavior, executive function, and negative emotionality. We included N = 593 participants from the enhanced Nathan Kline Institute-Rockland Sample community sample (ages 18-59, 67% female) that included N = 420 Controls and N = 173 with past SUDs [54% female; N = 75 Alcohol Use Disorder (AUD) only, N = 30 Cannabis Use Disorder (CUD) only, and N = 68 Multiple SUDs]. To test our a priori hypothesis that distinct neuro-behavioral subtypes exist within individuals with past SUDs, we conducted a latent profile analysis with all available phenotypic data as input (74 subscales from 18 measures), and then characterized resting-state brain function for each discovered subtype. Three subtypes with distinct neurobehavioral profiles were recovered (p < 0.05, Cohen's D: 0.4-2.8): a "Reward type" with higher approach-related behavior (N = 69); a "Cognitive type" with lower executive function (N = 70); and a "Relief type" with high negative emotionality (N = 34). For those in the Reward type, substance use mapped onto resting-state connectivity in the Value/Reward, Ventral-Frontoparietal and Salience networks; for the Cognitive type in the Auditory, Parietal Association, Frontoparietal and Salience networks; and for the Relief type in the Parietal Association, Higher Visual and Salience networks (pFDR < 0.05). Subtypes were equally distributed amongst individuals with different primary SUDs (χ2 = 4.71, p = 0.32) and gender (χ2 = 3.44, p = 0.18). Results support functionally derived subtypes, demonstrating considerable individual heterogeneity in the multi-dimensional impairments in addiction. This confirms the need for mechanism-based subtyping to inform the development of personalized addiction medicine approaches.

Brain networks alterations in cocaine use and gambling disorders during emotion regulation

Background

Cocaine use disorder (CUD) and gambling disorder (GD) share clinical features and neural alterations, including emotion regulation deficits and dysfunctional activation in related networks. However, they also exhibit differential aspects, such as the neuroadaptive effects of long-term drug consumption in CUD as compared to GD. Neuroimaging research aimed at disentangling their shared and specific alterations can contribute to improve understanding of both disorders.

Methods

We compared CUD (N = 15), GD (N = 16) and healthy comparison (HC; N = 17) groups using a network-based approach for studying temporally coherent functional networks during functional magnetic resonance imaging (fMRI) of an emotion regulation task. We focused our analysis in limbic, ventral frontostriatal, dorsal attentional (DAN) and executive networks (FPN), given their involvement in emotion regulation and their alteration in CUD and GD. Correlations with measures of emotional experience and impulsivity (UPPS-P) were also performed.

Results

The limbic network was significantly decreased during emotional processing both for CUD and GD individuals compared to the HC group. Furthermore, GD participants compared to HC showed an increased activation in the ventral frontostriatal network during emotion regulation. Finally, networks' activation patterns were modulated by impulsivity traits.

Conclusions

Functional network analyses revealed both overlapping and unique effects of stimulant and gambling addictions on neural networks underpinning emotion regulation.

Latent classes of maladaptive personality traits exhibit differences in social processing

OBJECTIVE

Social processing (SP) deficits manifest across numerous mental disorders. However, this research has been plagued by heterogeneity and a piecemeal approach whereby skills are examined in isolation rather than as part of an integrated cognitive system. Here, we combined two dimensional frameworks of psychopathology to address these limitations.

METHOD

We utilized the Alternative Model for Personality Disorders (AMPD) to distill trait-related heterogeneity within a community sample (n = 200), and the Research Domain Criteria (RDoC) 'Systems for Social Processes' to comprehensively assess SP. We first applied latent class analyses (LCA) to derive AMPD-based groups and subsequently contrasted the performance of these groups on a SP test battery that we developed to align with the RDoC SP constructs.

RESULTS

Our LCA yielded four distinct subgroups. The recognizable trait profiles and psychopathological symptoms of these classes suggested they were clinically meaningful. The subgroups differed in their SP profiles: one displayed deficits regarding the self, a second displayed deficits in understanding others, a third displayed more severe deficits including affiliation problems, whilst the fourth showed normal performance.

CONCLUSIONS

Our results support the link between clusters of maladaptive personality traits and distinctive profiles of SP deficits, which may inform research on disorders involving SP dysfunctions.

Profiles of patients with cocaine and alcohol use disorder based on cognitive domains and their relationship with relapse

BACKGROUND

Relapse in drug use constitutes a research topic on addiction that is relevant for understanding both the addictive process and its clinical implications. The objective of this study was to explore if it is possible to identify patient profiles according to their performance on cognitive tasks whilst examining the relationship between such profiles and relapse.

METHODS

The sample consisted of 222 patients with dependence on cocaine and / or alcohol, of which 86 % were men. Cognitive domains related to salience, decision- making, and emotional processing were measured.

RESULTS

Latent class analysis revealed three patient profiles that differ in terms of performance on cognitive tasks. Two of these profiles are clearly differentiated in terms of their execution of the impulsive decision-making task. The third patient profile, unlike the latter two, is composed of patients with severe alterations in the three domains evaluated. Analysis revealed that patients in Profile 3 are those with the highest rates of relapse in cocaine (Profile 1 = 40.3 %; Profile 2 = 35.6 %; Profile 3 = 69.2 %; Chi2 = 9.169; p < .05) and cocaine and alcohol use (Profile 1 = 55.1 %; Profile 2 = 54.1 %; Profile 3 = 80 %; Chi2 = 6.698; p < .05).

CONCLUSIONS

The results support the postulates of the I-RISA model. From a clinical perspective, these findings highlight the need for a comprehensive evaluation of the cognitive domains involved in addiction.

Impairments in Executive Functioning in Patients with Comorbid Substance Use and Personality Disorders: A Systematic Review

The purpose of this systematic review was to examine the evidence for impaired executive functioning in patients diagnosed with a dual pathology of personality disorder (PD) and substance use disorder, and to identify whether differences exist in comparison to those with a single diagnosis. Methods: A systematic search was conducted to identify studies using measures of executive functioning in patients with PD-substance use disorder dual pathology. Sixteen studies were selected. Results: The results indicate that dual pathology patients with Cluster C personality disorder do not differ from controls, and that the presence of dual pathology does not influence the updating domain of executive functioning. The findings were inconclusive with regard to dual pathology patients with Cluster B personality disorders. Whilst the various studies consistently show that these patients show worse performance than the control groups, here are contradictory results with regard to whether Cluster B personality disorders add more alterations in executive functioning to those that already appear in substance use disorder. Conclusions: The results suggest the need for further research that more adequately controls variables such as time in treatment, medication, and sample size, whilst there is also a need to employ longitudinal designs that include more patients from Clusters A and C.

Pathways to Recovery among Homeless People with Mental Illness: Is Impulsiveness Getting in the Way?

OBJECTIVE

This study investigates the association between impulsiveness and six dimensions of recovery among homeless people with mental illness.

METHOD

The sample was composed of 418 participants of a randomized controlled trial of Housing First, a recovery-oriented program that provides immediate access to permanent housing. The reliable change index method was used to provide an estimate of the statistical and clinical significance of the change from baseline to 24 months (i.e., clinically meaningful improvement), on outcomes that pertain to recovery dimensions: psychiatric symptoms (clinical), physical health and substance use problems (physical), residential stability (functional), arrests (criminological), community integration (social), and hope and personal confidence (existential). We tested for the effect of impulsiveness, assessed with the Barratt Impulsiveness Scale-11, on clinically meaningful improvement on each specific outcome, adjusting for age, gender and intervention assignment, as both intervention arms were included in the analysis.

RESULTS

For every increase in total impulsiveness score by one standard deviation, the odds of experiencing clinically meaningful improvement decreased by 29% (OR = 0.71, 95% CI, 0.55 to 0.91) on the clinical dimension and by 53% (OR = 0.47, 95% CI, 0.32 to 0.68) on the existential dimension. However, changes in outcomes pertaining to physical, functional, criminological, and social dimensions were not significantly influenced by impulsiveness.

CONCLUSIONS

Findings highlight the importance of addressing impulsiveness in the context of recovery-oriented interventions for homeless people with mental illness. Further research may be required to improve interventions that are responsive to unique needs of impulsive individuals to support clinical and existential recovery.

ALDH2 Gene: Its Effects on the Neuropsychological Functions in Patients with Opioid Use Disorder Undergoing Methadone Maintenance Treatment

Objective

Patients with opioid use disorder (OUD) have impaired attention, inhibition control, and memory function. The aldehyde dehydrogenase 2(ALDH2) gene has been associated with OUD and ALDH2 gene polymorphisms may affect aldehyde metabolism and cognitive function in other substance use disorder. Therefore, we aimed to investigate whether ALDH2 genotypes have significant effects on neuropsychological functions in OUD patients undergoing methadone maintenance therapy (MMT).

Methods

OUD patients undergoing MMT were investigated and followed-up for 12 weeks. ALDH2 gene polymorphisms were genotyped. Connors' Continuous Performance Test (CPT) and the Wechsler Memory Scale-Revised (WMS-R) were administered at baseline and after 12 weeks of MMT. Multivariate linear regressions and generalized estimating equations (GEEs) were used to examine the correlation between the ALDH2 genotypes and performance on the CPTs and WMS-R.

Results

We enrolled 86 patients at baseline; 61 patients completed the end-of-study assessments. The GEE analysis showed that, after the 12 weeks of MMT, OUD patients with the ALDH2 *1/*2＋*2/*2 (ALDH2 inactive) genotypes had significantly higher commission error T-scores (p= 0.03), significantly lower hit reaction time T-scores (p= 0.04), and significantly lower WMS-R visual memory index scores (p= 0.03) than did patients with the ALDH2 1*/*1 (ALDH2 active) genotype.

Conclusion

OUD patients with the ALDH2 inactive genotypes performed worse in cognitive domains of attention, impulse control, and memory than did those with the ALDH2 active genotype. We conclude that the ALDH2 gene is important in OUD and is associated with neuropsychological performance after MMT.

Quality of Life in Patients With Methamphetamine Use Disorder: Relationship to Impulsivity and Drug Use Characteristics

BACKGROUND

The quality of life (QOL) of patients with methamphetamine use disorder (MAUD) is increasingly recognized as an important outcome. Previous studies have found that impulsivity is negatively associated with QOL in mental disorders, but this relationship is rarely confirmed in patients with MAUD. We hypothesized that impulsivity is negatively correlated with QOL in patients with MAUD based on previous findings. In addition, a variety of drug use characteristics of patients that may potentially affect their QOL need to be further explored. Therefore, the purpose of this study was to explore the relationship between impulsivity, multiple drug use characteristics, and QOL in patients with MAUD.

METHODS

A total of 379 patients with MAUD were recruited, and the majority of them were male (85.5%), with an average age of 33.93 ± 7.08 years. Two psychiatrists conducted semi-structured interviews with methamphetamine (MA) users in two compulsory drug rehabilitation centers to obtain their demographics and drug use characteristics. The Barratt Impulsiveness Scale-11 (BIS-11) and Brief WHO Quality of Life Assessment (WHOQOL-BREF) were used to assess patients' impulsivity and QOL, respectively. Correlation and univariate regression analysis were used to explore the relationships between impulsivity, a series of drug use characteristics and patients' QOL in different domains. Further multiple linear regression analysis was used to identify what extent the above clinical variables explained the variations in patients' QOL.

RESULTS

Age, marital status, employment, and various drug use characteristics were significantly associated with at least one QOL domain. Among them, married and full-time job were positively correlated with QOL, while others were negatively correlated with QOL. The total score of BIS-11 was significantly negatively correlated with all four domains of QOL. Impulsivity, a range of drug use characteristics and certain demographic characteristics collectively explained varying degrees of variation in different domains of QOL.

CONCLUSIONS

Impulsivity and various drug use characteristics can significantly predict QOL in all fields of MAUD patients. In addition, we have also found differences in the predictors of QOL in different domains. Overall, this study provides clinical guidance for the treatment of MAUD patients, that is, management of impulsivity in patients with MAUD may help improve their QOL and even sustain their drug rehabilitation.

Impact of Substance Use Disorder Pharmacotherapy on Executive Function: A Narrative Review

Substance use disorders are chronic, relapsing, and harmful conditions characterized by executive dysfunction. While there are currently no approved pharmacotherapy options for stimulant and cannabis use disorders, there are several evidence-based options available to help reduce symptoms during detoxification and aid long-term cessation for those with tobacco, alcohol and opioid use disorders. While these medication options have shown clinical efficacy, less is known regarding their potential to enhance executive function. This narrative review aims to provide a brief overview of research that has investigated whether commonly used pharmacotherapies for these substance use disorders (nicotine, bupropion, varenicline, disulfiram, acamprosate, nalmefene, naltrexone, methadone, buprenorphine, and lofexidine) effect three core executive function components (working memory, inhibitory control and cognitive flexibility). While pharmacotherapy-induced enhancement of executive function may improve cessation outcomes in dependent populations, there are limited and inconsistent findings regarding the effects of these medications on executive function. We discuss possible reasons for the mixed findings and suggest some future avenues of work that may enhance the understanding of addiction pharmacotherapy and cognitive training interventions and lead to improved patient outcomes.

Impulsivity profiles in pathological slot machine gamblers

INTRODUCTION

In gambling disorder (GD), impulsivity has been related with severity, treatment outcome and a greater dropout rate. The aim of the study is to obtain an empirical classification of GD patients based on their impulsivity and compare the resulting groups in terms of sociodemographic, clinical and gambling behavior variables.

METHODS

126 patients with slot machine GD attending the Pathological Gambling Unit between 2013 and 2016 were included. The UPPS-P Impulsive Behavior Scale was used to assess impulsivity, and the severity of past-year gambling behavior was established with the Screen for Gambling problems questionnaire (NODS). Depression and anxiety symptoms and executive function were also assessed. A two-step cluster analysis was carried out to determine impulsivity profiles.

RESULTS

According to the UPPS-P data, two clusters were generated. Cluster 1 showed the highest scores on all the UPPS-P subscales, whereas patients from cluster 2 exhibited only high scores on two UPPS-P subscales: Negative Urgency and Lack of premeditation. Additionally, patients on cluster 1 were younger and showed significantly higher scores on the Beck Depression Inventory and on the State-Trait Anxiety Inventory questionnaires, worse emotional regulation and executive functioning, and reported more psychiatric comorbidity compared to patients in cluster 2. With regard to gambling behavior, cluster 1 patients had significantly higher NODS scores and a higher percentage presented active gambling behavior at treatment start than in cluster 2.

CONCLUSIONS

We found two impulsivity subtypes of slot machine gamblers. Patients with high impulsivity showed more severe gambling behavior, more clinical psychopathology and worse emotional regulation and executive functioning than those with lower levels of impulsivity. These two different clinical profiles may require different therapeutic approaches.

Impulsivity predicts poorer improvement in quality of life during early treatment for people with methamphetamine dependence

BACKGROUND AND AIMS

Methamphetamine dependence is associated with heightened impulsivity and diminished quality of life, but the link between impulsivity and changes in quality of life during treatment has not been examined. We aimed to investigate how different elements of impulsivity predict change in quality of life in the 6 weeks after engaging in treatment.

DESIGN

Longitudinal, observational cohort study.

SETTING

Public and private detoxification and rehabilitation facilities in metropolitan Melbourne, Australia.

PARTICIPANTS

One hundred and eight individuals with methamphetamine dependence (81 male) tested within 3 weeks of commencing treatment; 80 (74%) were followed-up at 6 weeks.

MEASUREMENTS

The Continuous Performance Test-2 measured impulsive action (cognitive and motor impulsivity); the Delay Discounting Task measured impulsive choice. Quality of life was measured with the World Health Organization Quality of Life Scale-Brief, which includes social, psychological, physical and environment domains. Control variables included age, gender, estimated IQ, depression severity score, methamphetamine dependence severity score, cannabis dependence severity score and treatment modality.

FINDINGS

We found that all three forms of impulsivity were significant predictors of change in the social domain: motor impulsivity (β = -0.54, P = 0.013), cognitive impulsivity (β = -0.46, P = 0.029) and impulsive choice (β = -0.26, P = 0.019). Change in the psychological domain was predicted significantly by motor impulsivity (β = -0.45, P = 0.046). Control variables of age and depression were associated significantly with changes in the physical domain.

CONCLUSIONS

In Australian methamphetamine-dependent individuals, elevated impulsivity predicts lower improvement of social and psychological quality of life in the first 6-9 weeks of treatment.

Latent Impulsivity Subtypes in Substance Use Disorders and Interactions with Internalizing and Externalizing Co-Occurring Disorders

This study explored the clinical importance of latent impulsivity subtypes within a sample of individuals with substance use disorders (SUDs) and high rates of co-occurring disorders (CODs) receiving residential treatment, aiming to assess the heterogeneity of the associations between SUDs and CODs across such impulsivity subtypes. The abbreviated Barratt impulsiveness scale was used to assess motor and cognitive (attentional and nonplanning) impulsivity, a structured interview for diagnosis of SUD and CODs, and other clinimetric measures for severity of substance use. Latent class analysis was conducted to extract subgroups of impulsivity subtypes and Poisson regression to analyze effects of interactions of classes by CODs on severity of substance use. 568 participants were evaluated. Results featured a four-class model as the best-fitted solution: overall high impulsivity (OHI); overall low impulsivity; high cognitive-low motor impulsivity; and moderate cognitive-low motor impulsivity (MC-LMI). OHI and MC-LMI concentrated on most of the individuals with CODs, and individuals within OHI and MC-LMI showed more severity of substance use. The expression of this severity relative to the impulsivity subtypes was modified by their interaction with internalizing and externalizing CODs in very heterogeneous ways. Our findings suggest that knowing either the presence of trait-based subtypes or CODs in individuals with SUDs is not enough to characterize clinical outcomes, and that the analysis of interactions between psychiatric categories and behavioral traits is necessary to better understand the expressions of psychiatric disorders.

Neurofeedback as a Treatment for Impulsivity in a Forensic Psychiatric Population With Substance Use Disorder: Study Protocol of a Randomized Controlled Trial Combined With an N-of-1 Clinical Trial

BACKGROUND

Impulsivity and substance use disorder (SUD) are strongly interconnected, with persons scoring high on impulsivity being more vulnerable to develop substance abuse, facing more challenges for successful treatment, and being more prone to engage in criminal behavior. Studies have shown that impulsivity and craving for substances are strongly correlated. Neurofeedback is an effective treatment to reduce impulsive behavior. This study intends to determine to what extent a neurofeedback-intervention that is aimed at reducing impulsivity can also reduce levels of craving in forensic patients with SUD and comorbid Axis I and/or II diagnoses.

OBJECTIVE

The main objective of this study is to investigate to what extent a reduction in impulsivity by a sensorimotor rhythm (SMR)-neurofeedback intervention will lead to a reduction in craving in a population of forensic psychiatric patients with a diagnosis of SUD.

METHODS

Participants will be male SUD patients with various comorbidities residing in an inpatient forensic treatment facility approached through treatment supervisors for participation. Participants have tested positive for drug use in the past 24 months. The study consists of 2 parts: a randomized controlled trial (RCT) and a n-of-1 clinical series. In the RCT, 50 patients will be randomly assigned to an intervention (n=25) or a control (n=25) condition. Patients in the intervention group will receive 20 SMR neurofeedback sessions aimed at reducing impulsivity; participants in the control group receive treatment-as-usual (TAU). Additionally, 4 in depth n-of-1 clinical trials will be conducted where effects of an SMR neurofeedback intervention will be compared to effects of sham neurofeedback.

RESULTS

Results of this study are expected by the end of 2017.

CONCLUSIONS

This protocol describes the design of a study testing the effects of an impulsivity-based neurofeedback protocol among forensic patients with SUD and various comorbidities. We expect a significant reduction in impulsive behavior, level of craving, and actual drug-use for participants receiving the SMR neurofeedback protocol. The n-of-1 approach might help to explain effects possibly found in the RCT study since it allows for a more direct focus on treatment effects by following participants more closely and thereby being able to directly attribute behavioral and neurophysiological change to the SMR neurofeedback protocol employed.

CLINICALTRIAL

Dutch National Trial Register NTR5386; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=5386 (Archived by WebCite at http://www.webcitation.org/6nXLQuoLl).

Impact of general cognition and executive function deficits on addiction treatment outcomes: Systematic review and discussion of neurocognitive pathways

This systematic review aims to examine growing evidence linking cognitive-executive functions with addiction treatment outcomes, and to discuss significant cognitive predictors drawing upon addiction neuroscience theory. We conducted a systematic search to identify studies using measures of general cognition and executive functions in patients with substance use disorders for the purpose of predicting two treatment outcomes: therapeutic adherence and relapse. Forty-six studies were selected, and sample characteristics, timing of assessments, and cognitive measures were analyzed. We observed significant methodological differences across studies, resulting in substantial variability in the relationships between cognitive-executive domains and treatment outcomes. Notwithstanding this variability, we found evidence of associations, of medium effect size, between general cognition and treatment adherence, and between reward-based decision-making and relapse. The link between general cognition and treatment adherence is consistent with emerging evidence linking limited cognitive-executive resources with less ability to benefit from talk therapies. The link between reward-based decision-making and relapse accords with decision neuroscience models of addiction. Findings may inform preclinical and clinical research concerning addiction treatment mechanisms.

Cognitive Mechanisms and Therapeutic Targets of Addiction

Fundamental to cognitive models of addiction is the gradual strengthening of automatic, urge-related responding that develops in tandem with the diminution of self-control-related processes aimed at inhibiting impulses. Recent conceptualizations of addiction also include a third set of cognitive processes related to self-awareness and superordinate regulation of self-control and other higher brain function. This review describes new human research evidence and theoretical developments related to the multicausal strengthening of urge-related responding and failure of self-control in addiction, and the etiology of disrupted self-awareness and rational decision-making associated with continued substance use. Recent progress in the development of therapeutic strategies targeting these mechanisms of addiction is reviewed, including cognitive bias modification, mindfulness training, and neurocognitive rehabilitation.

Co-occurrence of alcohol use disorder and behavioral addictions: relevance of impulsivity and craving

PURPOSE

The aims of the study were to evaluate the occurrence of behavioral addictions (BAs) in alcohol use disorder (AUD) subjects and to investigate the role of impulsivity, personality dimensions and craving.

METHODS

95 AUD outpatients (DSM-5) and 140 homogeneous controls were assessed with diagnostic criteria and specific tests for gambling disorder, compulsive buying, sexual, internet and physical exercise addictions, as well as with the Barratt Impulsiveness Scale (BIS-11) and Temperamental and Character Inventory-Revised (TCI-R). The Obsessive Compulsive Drinking Scale (OCDS) and Visual Analogue Scale for craving (VASc) were also administered to the AUD sample.

RESULTS

28.4% (n=27) of AUD subjects had at least one BA, as compared to 15% (n=21) of controls (χ(2)=6.27; p=.014). In AUD subjects, direct correlations between BIS-11 and Compulsive Buying Scale (CBS), Internet Addiction Disorder test (IAD), Exercise Addiction Inventory-Short Form (EAI-SF) scores (p<.01), between OCDS obsessive and CBS and VASc and CBS, IAD scores (p<.003), were found. BIS-11 (t=-2.36; p=.020), OCDS obsessive (Z=-4.13; p<.001), OCDS compulsive (Z=-2.12; p=.034) and VASc (Z=-4.94; p<.001) scores were higher in AUD subjects with co-occurring BAs. The occurrence of BAs was associated with higher impulsivity traits (BIS-11 scores; OR=1.08; p=.012) and higher craving levels (VASc scores; OR=2.48; p<.001).

CONCLUSIONS

Our findings emphasize a significant rate of co-occurrence of BAs in AUD. High levels of impulsivity and craving for alcohol seem to be associated with other addictive behaviors.