Relationship of personality traits and drug of choice by cocaine addicts and heroin addicts

'Can we predict aggression?'-Determining the predictors of aggression among individuals with substance use disorder in China undergoing enforced detoxification through machine learning

BACKGROUND

The general aggression model has shown that both individual and situational factors can predict aggression. However, past research has tended to discuss these two factors separately, which might lead to inconsistency. This study addresses this gap by examining the importance of each predictor of aggression in a Chinese compulsory drug treatment population and further explores the predictors of aggression in various substance use disorder populations.

METHOD

Analyses were conducted using a sample of 894 male participants (mean = 38.30, SD = 8.38) in Chinese compulsory drug rehab. A machine learning model named LightGBM was employed to make predictions. We then used a game-theoretic explanatory technique, SHAP, to estimate the effect of predictors.

RESULTS

In the full-sample model, psychological security, parental conflict, and impulsivity were the top 3 predictors. Depression, childhood abuse, and alexithymia positively predicted aggression, whereas psychological security, family cohesion, and gratitude negatively predicted aggression. There were significant differences in the predictive effects of depressants and stimulants. Although the importance of predictors varied between drug-use groups, several individual and situational factors were consistently the most important predictors.

LIMITATIONS

All participants in this study were male, and the data were acquired through self-reports from the participants. Domestic and nondomestic aggression are not distinguished. Additionally, our findings cannot support causal conclusions.

CONCLUSION

This study tested a series of classical theories of the predictors of aggression in China's compulsory drug treatment context and extended the ideas of the GAM to various substance use disorder groups. The findings have important implications for aggression treatment.

Illicit drug use and male barroom aggression among members of the Australian construction industry: Associations with personality and masculinity factors

Introduction

Illicit drug use has been found to increase the risks of male barroom aggression (MBA). Personality traits such as dispositional aggressiveness have been associated with illicit substance use and aggressive behaviour, along with social normative masculinity factors. The present study assessed the relationships between illicit drug use, key personality (trait aggression, impulsivity, narcissism) and masculinity (conformity to masculine norms, male honour) variables with physical MBA perpetration and victimisation among male Australian construction workers.

Methods

A purposive, high‐risk sample of male construction workers aged 18–69 years (n = 476, M_age = 25.90 years, SD_age = 9.44) completed interviews at their place of work or training.

Results

Participants reported high rates of both physical MBA perpetration (21%; n = 100) and victimisation (31.1%; n = 148) as well as any illicit drug use (33.61%; n = 160). Logistic regressions revealed the use of amphetamine‐type stimulants (methamphetamine, ecstasy) was associated with violence perpetration, even after accounting for high‐intensity drinking (HID) which was the strongest predictor of MBA involvement. Trait variables (Trait Physical aggressiveness, narcissism) and the masculine norm CMNI Violence were also risk factors for MBA perpetration while CMNI Playboy was protective against MBA.

Discussion and Conclusions

The use of amphetamine‐type stimulants is a risk‐factor for MBA perpetration, as are key personality traits such as aggressiveness and narcissism. Most aspects of masculinity, including male honour, were either unrelated to or protective against involvement in physical violence in bars, clubs or pubs.

COVID-19 Pandemic Impact on Substance Misuse: A Social Media Listening, Mixed Method Analysis

The restrictive measures adopted during the COVID-19 pandemic modified some previously consolidated drug use patterns. A focus on social networks allowed drug users to discuss, share opinions and provide advice during a worldwide emergency context. In order to explore COVID-19-related implications on drug trends/behaviour and on most popular psychotropic substances debated, the focus here was on the constantly updated, very popular, Reddit social platform’s posts and comments. A quantitative and qualitative analysis of r/Drugs and related subreddits, using a social media listening netnographic approach, was carried out. The post/comments analysed covered the time-frame December 2019–May 2020. Between December 2019 and May 2020, the number of whole r/Drugs subreddit members increased from 619,563 to 676,581 members, respectively, thus increasing by 9.2% by the end of the data collection. Both the top-level r/Drugs subreddit and 92 related subreddits were quantitatively analysed, with posts/comments related to 12 drug categories. The drugs most frequently commented on included cannabinoids, psychedelics, opiates/opioids, alcohol, stimulants and prescribed medications. The qualitative analysis was carried out focussing on four subreddits, relating to some 1685 posts and 3263 comments. Four main themes of discussion (e.g., lockdown-associated immunity and drug intake issues; drug-related behaviour/after-quarantine plans’ issues; lockdown-related psychopathological issues; and peer-to-peer advice at the time of COVID-19) and four categories of Redditors (e.g., those continuing the use of drugs despite the pandemic; the “couch epidemiologists”; the conspirationists/pseudo-science influencers; and the recovery-focused users) were tentatively identified here. A mixed-methods, social network-based analysis provided a range of valuable information on Redditors’ drug use/behaviour during the first phase of the COVID-19 pandemic. Further studies should be carried out focusing on other social networks as well as later phases of the pandemic.

Impact of Endoscopists' Personality Traits on Adenoma and Polyp Detection Rates in Colonoscopy: A KASID Multicenter Study

BACKGROUND

The personality traits of endoscopists have been suggested to affect the adenoma detection rate (ADR). We thus evaluated the relationship between endoscopists' personality traits and the ADR during colonoscopy using the Minnesota Multiphasic Personality Inventory-2 (MMPI-2).

METHODS

In total, 1230 patients (asymptomatic and aged 50-80 years) who underwent screening or surveillance (≥ 5 years) colonoscopy were recruited from 13 university hospitals by 20 endoscopists between September 2015 and December 2017. We retrospectively measured the ADR, polyp detection rate (PDR), and number of adenomas per colonoscopy (APC). All 20 endoscopists completed all 567 true/false MMPI-2 items.

RESULTS

The overall mean colonoscopy withdrawal time, PDR, ADR, and APC were 7.3 ± 2.8 min, 55%, 45.3%, and 0.97 ± 1.58, respectively. No significant difference was observed in the MMPI-2 clinical scales (e.g., hypochondriasis and psychasthenia), content scales (e.g., obsessiveness and type A character), or supplementary scales (e.g., dominance and social responsibility) between the high ADR group (ADR ≥45%, n = 10) and the low ADR group (ADR < 45%, n = 10). In multivariate logistic regression analysis, the ADR was associated significantly with patient age and sex. The ADR was related significantly to endoscopists' colonoscopy experience and the per-minute increase in the colonoscopy withdrawal time (OR 1.21, 95% CI 1.06-1.38, p = 0.005). In a logistic regression analysis adjusted for patient factors, the ADR was associated significantly with ego strength (OR 1.04, 95% CI 1.00-1.09, p = 0.044), as measured by the MMPI-2.

CONCLUSIONS

With the exception of ego strength, the endoscopists' personality traits were not associated with adenoma or polyp detection.

Molecular Imaging of Opioid and Dopamine Systems: Insights Into the Pharmacogenetics of Opioid Use Disorders

Opioid use in the United States has steadily risen since the 1990s, along with staggering increases in addiction and overdose fatalities. With this surge in prescription and illicit opioid abuse, it is paramount to understand the genetic risk factors and neuropsychological effects of opioid use disorder (OUD). Polymorphisms disrupting the opioid and dopamine systems have been associated with increased risk for developing substance use disorders. Molecular imaging studies have revealed how these polymorphisms impact the brain and contribute to cognitive and behavioral differences across individuals. Here, we review the current molecular imaging literature to assess how genetic variations in the opioid and dopamine systems affect function in the brain's reward, cognition, and stress pathways, potentially resulting in vulnerabilities to OUD. Continued research of the functional consequences of genetic variants and corresponding alterations in neural mechanisms will inform prevention and treatment of OUD.

Psychological features of abstinent heroin users before and after rehabilitation in Saint Petersburg, Russia

Objective

The objective of the study was to describe psychological features of abstinent heroin users undergoing rehabilitation in Saint Petersburg, Russia. Study subjects (n = 197) were recruited prospectively at the time of their admission to rehabilitation between March 2010 and May 2011 at 7 inpatient opiate addiction rehabilitation centers in Saint-Petersburg and neighboring regions, Russia. The centers provided varying rehabilitation programs; 6 of them were religious centers. Socio-demographic information and self-reported HIV status were collected. Personality profiles and severity of drug-associated problems were estimated before and after rehabilitation using the Minnesota Multiphasic Personality Inventory 2 (MMPI-2), and the Addiction Severity Index (ASI).

Results

Thirty-three (17%) subjects dropped out before completing rehabilitation (non-completers). All subjects (completers and non-completers) had psychopathological personality profiles according to MMPI-2. These profiles were refractory to clinically significant improvement after rehabilitation, although some statistically significant changes toward improvement were observed. ASI scores showed statistically and clinically significant improvements after rehabilitation on all scales. Participants in longer-term versus shorter-term rehabilitation programs showed similar changes in their pre- and post-rehabilitation MMPI-2 and ASI scores. Our results suggest that unmet psychiatric needs should be addressed to potentially improve treatment completion in this population.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3699-5) contains supplementary material, which is available to authorized users.

Gaging the impact of multiple substance use on community corrections involvement

Historically, research has demonstrated that multiple substance use, compared to single substance use, poses additional challenges for treatment throughout the continuum of care including referrals, interventions, and relapse prevention. However, it appears that this pattern cannot be easily generalized to all criminal justice settings as evidenced by mixed findings across criminal justice samples. The purpose of the current study is to investigate possible differences in legal and substance-related outcomes between multiple substance users and single substance users within a community corrections sample. Structured clinical interviews were conducted to divide 531 individuals under community corrections supervision into three groups including multiple substance users, single substance users, and non-substance users. Results indicated that while multiple substance users were arrested more frequently and had more problems with family members, there were no differences compared to their single substance using counterparts in terms of depressive disorders, anxiety disorders, or types of offense. These findings contrast with previous research on samples outside of community corrections suggesting that multiple substance use requires tailored interventions with consideration to context of their use. Discussion includes limitations to generalizability and assessment of substance use as well as implications for treatment and future research.

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.

The Mediating Role of Autonomy and Relatedness on Maternal and Child Outcomes

The current study examined the mediating role of both mother and child interactive behaviors, which granted or undermined autonomy and relatedness, on the bidirectional and longitudinal association between maternal depressive symptoms and child internalizing behaviors, as well as the association between maternal substance use and child externalizing behaviors. Child's sex and mother's drug of choice were explored as potential moderators of the mediation relationship. Data were collected from 183 dyads including treatment-seeking substance using mothers and their children (95 males, aged between 8 and 16 years old). Structural equation modeling analysis showed girls' internalizing and externalizing behaviors at the 3-month follow-up were negatively associated with the same behaviors at the 12-month follow-up through increased relatedness undermining behaviors from their mothers at the 6-month follow-up. Among mothers with opioids as their drug of choice (DOC), children's externalizing behaviors at the 3-month follow-up were positively associated with mothers' substance use at the 12-month follow-up through the elevated levels of mothers' relatedness undermining behaviors at the 6-month follow-up. Among mothers with alcohol as their DOC, maternal depressive symptoms at the 3-month follow-up were positively related to children's internalizing behaviors at the 12-month follow-up through reduced relatedness undermining behaviors exhibited by mothers at the 6-month follow-up. To our knowledge, this is one of the first studies to attempt to unravel these longitudinal and bidirectional influences as well as the moderated mediation pathways among families with a substance using mothers.

Exaggerated acquisition and resistance to extinction of avoidance behavior in treated heroin-dependent men

OBJECTIVE

Addiction is often conceptualized as a behavioral strategy for avoiding negative experiences. In rodents, opioid intake has been associated with abnormal acquisition and extinction of avoidance behavior. Here, we tested the hypothesis that these findings would generalize to human opioid-dependent subjects.

METHOD

Adults meeting DSM-IV criteria for heroin dependence and treated with opioid medication (n = 27) and healthy controls (n = 26) were recruited between March 2013 and October 2013 and given a computer-based task to assess avoidance behavior. For this task, subjects controlled a spaceship and could either gain points by shooting an enemy spaceship or hide in safe areas to avoid on-screen aversive events. Hiding duration during different periods of the task was used to measure avoidance behavior.

RESULTS

While groups did not differ on escape responding (hiding) during the aversive event, heroin-dependent men (but not women) made more avoidance responses during a warning signal that predicted the aversive event (analysis of variance, sex × group interaction, P = .007). Heroin-dependent men were also slower to extinguish the avoidance response when the aversive event no longer followed the warning signal (P = .011). This behavioral pattern resulted in reduced opportunity to obtain reward without reducing risk of punishment. Results suggest that, in male patients, differences in avoidance behavior cannot be easily explained by impaired task performance or by exaggerated motor activity.

CONCLUSIONS

This study provides evidence for abnormal acquisition and extinction of avoidance behavior in opioid-dependent patients. Interestingly, data suggest that abnormal avoidance is demonstrated only by male patients. Findings shed light on cognitive and behavioral manifestations of opioid addiction and may facilitate development of therapeutic approaches to help affected individuals.

Commonalities and Differences Across Substance Use Disorders: Phenomenological and Epidemiological Aspects

BACKGROUND

Although psychoactive substances vary in many ways, they have important commonalties, particularly in their ability to lead to an addiction syndrome. The field lacks an updated review of the commonalities and differences in the phenomenology of alcohol, cannabis, tobacco, stimulants, opioids, hallucinogens, sedatives/tranquilizers, and inhalants and their related substance use disorders (SUDs).

METHODS

DSM-IV and DSM-5 SUD diagnostic criteria were reviewed, as was evidence from recent epidemiological and clinical research: psychometric studies (test-retest reliability, latent trait analysis); physiological indicators (tolerance, withdrawal); prevalence and age of onset. Information was incorporated from previous reviews, PubMed and Scopus literature searches, and data from large U.S. national surveys.

RESULTS

Empirical evidence in the form of test-retest reliability and unidimensionality supports use of the same DSM-IV dependence or DSM-5 SUD diagnostic criteria across substances. For most substances, the criteria sets were generally most informative in general population samples at moderate-to-severe levels of SUD. Across substances, 2 criteria (tolerance and use in hazardous situations) were identified as functioning differently in population subgroups. Since substances have different pharmacological effects, withdrawal is assessed using substance-specific symptoms, while tolerance is not; issues remain with the assessment of tolerance. Alcohol, tobacco, and cannabis were consistently identified as the substances with earliest onset of use, highest prevalence of lifetime use, and highest prevalence of lifetime disorder.

CONCLUSIONS

Despite differences between psychoactive substances, the generic DSM criteria set appears equally applicable across substances. Additional studies of tolerance and hazardous use will be useful for future nosologies. Alcohol, cannabis, and tobacco are the substances with the greatest public health impact due to the high prevalence and early onset of their use, and the potential all 3 substances have to lead to addiction.

How do drug market changes affect characteristics of injecting initiation and subsequent patterns of drug use? Findings from a cohort of regular heroin and methamphetamine injectors in Melbourne, Australia

BACKGROUND

Changes in drug market characteristics have been shown to affect drug use patterns but few studies have examined their impacts on injecting initiation experiences and subsequent patterns of injecting drug use (IDU).

METHODS

We collected data on self-reported injecting initiation experiences and past-month patterns of IDU from 688 regular heroin and methamphetamine injectors in Melbourne, Australia, who initiated injecting across three different drug market periods (prior to the Australian heroin shortage ('high heroin')/immediately following the shortage ('low heroin')/'contemporary' markets (fluctuating heroin and methamphetamine availability)). We used univariable and multivariable logistic regression to examine the relationship between period of injecting initiation and first drug injected, and multinomial logistic regression for the relationship between period of injecting initiation and current injecting patterns.

RESULTS

425 participants (62%) reported initiating injecting in the high heroin period, 146 (21%) in the low heroin period, and 117 (17%) in the contemporary period. Participants who initiated injecting during the low heroin period were twice as likely to initiate injecting using a drug other than heroin (AOR: 1.94, 95% CI: 1.27-2.95). The most common patterns of drug use among study participants in the month preceding interview were polydrug use (44%) and primary heroin use (41%). Injecting initiation period was either non-significantly or weakly associated with current drug use pattern, which was more strongly associated with other socio-demographic and drug use characteristics, particularly self-reported drug of choice.

CONCLUSION

The drug market period in which injecting initiation occurred influenced the first drug injected and influenced some aspects of subsequent drug use. In the context of highly dynamic drug markets in which polydrug use is common there is a need for broad harm reduction and drug treatment services which are flexible and responsive to changing patterns of drug use.

NrCAM-regulating neural systems and addiction-related behaviors

We have previously shown that a haplotype associated with decreased NrCAM expression in brain is protective against addiction vulnerability for polysubstance abuse in humans and that Nrcam knockout mice do not develop conditioned place preferences for morphine, cocaine or amphetamine. In order to gain insight into NrCAM involvement in addiction vulnerability, which may involve specific neural circuits underlying behavioral characteristics relevant to addiction, we evaluated several behavioral phenotypes in Nrcam knockout mice. Consistent with a potential general reduction in motivational function, Nrcam knockout mice demonstrated less curiosity for novel objects and for an unfamiliar conspecific, showed also less anxiety in the zero maze. Nrcam heterozygote knockout mice reduced alcohol preference and buried fewer marbles in home cage. These observations provide further support for a role of NrCAM in substance abuse including alcoholism vulnerability, possibly through its effects on behavioral traits that may affect addiction vulnerability, including novelty seeking, obsessive compulsion and responses to aversive or anxiety-provoking stimuli. Additionally, in order to prove glutamate homeostasis hypothesis of addiction, we analyzed glutamatergic molecules regulated by NRCAM expression. Glutaminase appears to be involved in NrCAM-related molecular pathway in two different tissues from human and mouse. An inhibitor of the enzyme, prolyl-leucyl-glycinamide, treatment produced, at least, some of the phenotypes of mice shown in alcohol preference and in anxiety-like behavior. Thus, NrCAM could affect addiction-related behaviors via at least partially modulation of some glutamatergic pathways and neural function in brain.

The economic cost of heroin dependency and quality of life among heroin users in Taiwan

Heroin dependence may cause an economic burden and has an impact on quality of life (QOL). However, assessments of economic cost are scarce and the relationship between economic cost and QOL is unclear in the Asian population. In the present study, an established questionnaire was modified to assess the economic cost and its association with QOL. A total of 121 volunteer subjects in a methadone maintenance therapy programme and 157 normal controls were enrolled. The total economic cost of heroin dependency is US$ 18,310 per person-year. The direct cost is US$ 11,791 per person-year (64% of the total cost), mostly consisting of the cost of heroin and other illegal drugs. The indirect cost is US$ 6519 (36% of the total cost) per person-year, most of which arises from productivity loss caused by unemployment and incarceration. The QOL of heroin-dependent patients is poorer than that of healthy controls in all domains. The overall QOL is negatively related to direct cost and total cost. The economic cost of heroin dependency is huge, equal to 1.07 times the average gross domestic product per capita. Reduction of the economic cost to society and the economic burden for heroin users is important.

The dopamine receptor D1 gene is associated with the length of interval between first heroin use and onset of dependence in Chinese Han heroin addicts

Previous researches showed that the dopamine receptor D1 (DRD1) may play a critical role in drug dependence. This research aimed to determine whether DRD1 played a role in development of heroin dependence in Chinese heroin-dependent patients. 465 Chinese Han heroin-dependent subjects and 379 healthy controls were recruited in the Shanghai region. Five single-nucleotide-polymorphisms (SNPs) of the DRD1 gene were genotyped in all subjects. The results found that the frequencies of DRD1 SNP genotypes or haplotypes were not different between heroin-dependent patients and controls. Among heroin-dependent patients, subjects with rs5326CC and/or rs6882300AA genotypes develop to heroin-dependent more rapidly than those without rs5326CC and/or rs6882300AA genotypes. The results indicated that DRD1 gene polymorphism may not play an important role in the susceptibility of heroin dependence in the Chinese Han population, but it may be associated with the rapidity of heroin dependence development from first drug use.

What does self-identified drug of choice tell us about individuals under community corrections supervision?

OBJECTIVES

The term "drug of choice" (DOC) refers to substance abusers' preferred drug and this information often adds to the clinical picture of the patient because substance users often meet diagnostic criteria for dependence on multiple drugs. Characteristics such as age, race, marital status, and psychiatric illnesses have been shown to differentiate among individuals with different DOC preferences. However, no studies have examined DOC in the context of criminal behavior and other drug dependencies.

METHODS

The participants (N = 15,475) of a community corrections program, Treatment Alternatives for Safer Communities (TASC), were classified by DOC for the 4 main drugs of abuse (alcohol, marijuana, cocaine, and opioids) and each drug class was compared with the other 3 DOC using binary logistic regression.

RESULTS

Alcohol as DOC was associated with being older, white, male, having private health insurance, being medicated for a mental health disorder, and having a criminal history of person offenses. Cocaine as DOC was associated with being older, black, female, attempting suicide, having less than a high school education, living in a shelter or with relatives, being unemployed, being uninsured, being physically and sexually abused, and committing property and court offenses but not person or substance offenses. Marijuana as DOC was associated with being younger, black, male, never being married, and committing substance but not property or court offenses. Opioids as DOC were associated with being white, female, being married, higher education, being unemployed, and being medicated for a mental health disorder.

CONCLUSIONS

Overall, there were substantial differences between the 4 DOC groups, and the results are commensurate with expectations based on the abuse and dependency literature.

Responses to novelty and vulnerability to cocaine addiction: contribution of a multi-symptomatic animal model

Epidemiological studies have revealed striking associations between several distinct behavioral/personality traits and drug addiction, with a large emphasis on the sensation-seeking trait and the associated impulsive dimension of personality. However, in human studies, it is difficult to identify whether personality/behavioral traits actually contribute to increased vulnerability to drug addiction or reflect psychobiological adaptations to chronic drug exposure. Here we show how animal models, including the first multi-symptomatic model of addiction in the rat, have contributed to a better understanding of the relationships between different subdimensions of the sensation-seeking trait and different stages of the development of cocaine addiction, from vulnerability to initiation of cocaine self-administration to the transition to compulsive drug intake. We argue that sensation seeking predicts vulnerability to use cocaine, whereas novelty seeking, akin to high impulsivity, predicts instead vulnerability to shift from controlled to compulsive cocaine use, that is, addiction.

Drug specificity in extended access cocaine and heroin self-administration

Increased drug availability can precipitate a rapid escalation of drug consumption in both vulnerable humans and laboratory animals. Drug intake escalation is observed across a broad spectrum of drugs of abuse, including stimulants, opiates, ethanol and phencyclidine. Whether and to what extent the processes underlying escalated levels of drug intake vary across different substances is poorly understood. The present study sought to address this question in rats self-administering both cocaine and heroin-two addictive drugs with both common and different neurobiological effects. In experiment 1, we determined how cocaine intake is initially related to heroin intake in non-escalated rats with a limited access to both drugs. In experiment 2, two groups of rats were initially allowed to self-administer either cocaine or heroin for 1 hour per day and then after behavioral stabilization, for 6 hours per day to precipitate drug intake escalation. In each group, dose-injection functions for cocaine and heroin self-administration were generated. In experiment 1, regardless of the dose, rats with a high intake of one drug did not necessarily have a high intake of the alternate drug. In experiment 2, escalated levels of heroin or cocaine self-administration did not generalize to the other drug. This outcome was confirmed in a third drug substitution experiment following different access lengths to cocaine self-administration (i.e. 1, 4 and 8 hours). The processes underlying spontaneous and escalated drug overconsumption appear thus to vary across different drugs of abuse. More research should be devoted in the future to these differences.

Comparison of personality characteristics in Parkinson disease patients with and without impulse control disorders and in healthy volunteers

OBJECTIVE

We aimed to assess personality characteristics in patients with Parkinson disease (PD) with and without impulse control disorders (ICD).

METHODS

We tested patients and controls with the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) scales that have expected high sensitivity to apparent addictive behavior. We recorded mean disease duration and mean levodopa dose in the PD groups.

RESULTS

Of the 46 PD patients, 13 had ICD: hypersexuality, binge eating, or dopamine dysregulation. The PD patients with ICD had a longer duration of disease (11 vs. 5 y) and were taking higher doses of levodopa (900 vs. 500 mg/d). They scored above the pathologic threshold in 4 domains of the MMPI-2 Clinical Scales and in 8 Clinical Subscales and Content Scales. The most significant abnormality was Alienation-Self and Others.

CONCLUSIONS

ICDs in the general population have similarities to disorders of substance addiction. In PD patients, some personality profiles could play a role in development of ICDs or dopamine dysregulation syndrome. The MMPI-2 may be a useful test for PD patients in general, and for detecting ICD in particular.

The profile and familiality of personality traits in mood disorder families

OBJECTIVE

Personality traits have impacts on individuals' response to stress and mood expression. The current study aimed to investigate the profile of personality traits in patients with bipolar disorders and major depressive disorder (MDD). Familial aggregation of personality traits in mood disorder families was also evaluated.

METHODS

We recruited 260 clinical patients of MDD (92), bipolar disorder-I and II (BP-I=111, BP-II=57), 190 first-degree relatives, and 180 controls. Four personality traits were assessed using the Eysenck and Tridimensional Personality Questionnaires, including Extraversion (E), Neuroticism (N), Harm Avoidance (HA), and Novelty Seeking (NS). The magnitude of familiality of personality traits in mood disorder families was evaluated by mixed models and intra-class correlation coefficients (ICC).

RESULTS

Patients with mood disorders had lower E, and higher N, HA and NS than controls. Unaffected relatives were not differed from controls in the four personality traits. BP-I had higher E, NS and lower N, HA than MDD patients (p<0.01). The scale N further distinguished BP-I from BP-II (p=0.02) with lower N among BP-I patients. There exhibited moderate familiality in E (ICC=0.184-0.239) and HA (ICC=0.355) in bipolar disorder families.

LIMITATION

Personality traits were accessed cross-sectionally without quantitatively controlled severity of mood symptoms.

CONCLUSION

Different patterns of personality traits distinguish patients from unaffected individuals as well as separate diagnoses of mood disorders, indicating the usage of more comprehensive evaluation of personality traits in clinical settings. Familiality of extraversion and harm avoidance in bipolar disorder families provides insights for further investigating correlates of comorbid behavioral problems in bipolar disorders.

Tridimensional personalities and polymorphism of dopamine D2 receptor among heroin addicts

BACKGROUND

Drug addiction is a multifactorial disorder. Researchers have posited that an individual's inherited behavioral propensity or temperament contributes to the disorder by shaping a personality strongly linked with the risk of drug abuse. Further, they hypothesize that the polymorphism of dopamine D2 receptor increases the susceptibility to and severity of addiction. We, therefore, investigated possible associations between dopamine D2 receptor (DRD2) and personality traits among intravenous heroin addicts.

METHODS

We assessed 93 intravenous heroin addicts and controls using Diagnostic and Statistical Manual, Fourth Edition (DSM-IV) and the Tridimensional Personality Questionnaire (TPQ). We confirmed drug-dependence status using a questionnaire based on DSM-IV criteria. We extracted DNA from the subjects' whole blood and genotyped it for DRD2 allelic variants.

RESULTS

Genotype analysis showed a significantly higher frequency for the TaqIA polymorphism among the addicts (69.9%) compared to control subjects (42.6%; Fisher's exact χ(2), p < .05). We observed no significant differences for other variants between the addicts and controls. The addicts had higher scores for novelty seeking (NS) and harm avoidance (HA) personality traits but lower scores for reward dependence (RD) when compared to control subjects.

LIMITATION

The environmental cues are different for the addicts, and the healthy university students we used as controls. We recommend that researchers employ a gene-environment interaction approach to study factors associated with addictive behaviors in future studies.

CONCLUSION

Taq1A may be implicated for an increased vulnerability to addiction. Screening of this marker might be useful for identifying individuals at risk of addiction.

Mental health improvements of substance-dependent clients after 4 months in a Therapeutic Community

INTRODUCTION AND AIMS

Odyssey House Victoria's Therapeutic Community (TC) accepts substance-dependent clients, including those with co-occurring mental health issues. American data suggest that TCs are effective in rehabilitating such clients; however, Australian research is limited. The aim of the study was to examine Minnesota Multiphasic Personality Inventory-2 (MMPI-2) profiles of Odyssey House TC residents early in their residency and again after 4 months, to chart changes in MMPI-2 profiles and compare them with norms for psychological health.

DESIGN AND METHODS

The sample comprised 351 clients who were part of the residential program between 1997 and 2007, and who remained in treatment at the TC for at least 4 months. They were administered the MMPI-2 after 5 weeks in treatment and again after 4 months.

RESULTS

At the first assessment, the validity scales of the MMPI-2 plus the clinical scales Depression, Psychopathic Deviate, Paranoia, Psychasthenia and Schizophrenia were in the clinical range. At the second assessment, mean scores on all clinical scales except Mania were significantly or near significantly lower and, except for Psychopathic Deviate, within the normal range. The validity scales also demonstrated improvement, although two of the three remained in the clinical range.

DISCUSSION AND CONCLUSIONS

Results indicated that treatment within the TC over this time span was associated with improved mental health. The present study suggests that residential rehabilitation's holistic approach provides a suitable treatment model for clients with co-occurring mental health and substance use disorders.