Profiles of substance use disorders in patients of therapeutic communities: link to social, medical and psychiatric characteristics

A latent class analysis of mental disorders, substance use, and aggressive antisocial behavior among Swedish forensic psychiatric patients

BACKGROUND

Patients in the forensic mental health services (FMHS) with a mental disorder, a co-occurring substance use disorder (SUD), and high risk of aggressive antisocial behavior (AAB) are sometimes referred to as the 'triply troubled'. They suffer poor treatment outcomes, high rates of criminal recidivism, and increased risk of drug related mortality. To improve treatment for this heterogeneous patient group, more insight is needed concerning their co-occurring mental disorders, types of substances used, and the consequent risk of AAB.

METHODS

A three-step latent class analysis (LCA) was used to identify clinically relevant subgroups in a sample of patients (n = 98) from a high-security FMHS clinic in Sweden based on patterns in their history of mental disorders, SUD, types of substances used, and AAB.

RESULTS

A four-class model best fit our data: class 1 (42%) had a high probability of SUD, psychosis, and having used all substances; class 2 (26%) had a high probability of psychosis and cannabis use; class 3 (22%) had a high probability of autism and no substance use; and class 4 (10%) had a high probability of personality disorders and having used all substances. Both polysubstance classes (1 and 4) had a significantly more extensive history of AAB compared to classes 2 and 3. Class 3 and class 4 had extensive histories of self-directed aggression.

CONCLUSIONS

The present study helps disentangle the heterogeneity of the 'triply troubled' patient group in FMHS. The results provide an illustration of a more person-oriented perspective on patient comorbidity and types of substances used which could benefit clinical assessment, treatment planning, and risk-management among patients in forensic psychiatric care.

Monitoring adherence and abstinence of cannabis use disorder patients: Profile identification and relationship with long-term treatment outcomes

BACKGROUND

Patients with cannabis use disorder (CUD) show heterogeneous sociodemographic and consumption patterns. Although previous studies, focused on identifying subgroups of CUD patients using input variables, have yielded useful results for planning individualized treatments, no published research has analyzed the profiles of CUD patients according to their therapeutic progress. This study therefore aims to identify subgroups of patients using adherence and abstinence indicators and to explore whether these profiles are associated with sociodemographic characteristics, consumption variables, and long-term therapeutic outcomes.

METHODS

This was a retrospective observational study with a multisite sample of 2055 CUD outpatients who were beginning treatment. The study monitored patient data at two-year follow-up. We conducted latent profiles analysis on the appointment attendance ratio and percentage of negative cannabis tests.

RESULTS

A three profile solution emerged: i) moderate abstinence/moderate adherence (n = 997); ii) high abstinence/moderate adherence (n = 613); and iii) high abstinence/high adherence (n = 445). The study found the most marked differences at the beginning of treatment for education level (chi² (8) = 121.70, p < .001), source of referral (chi² (12) = 203.55, p < .001), and frequency of cannabis use (chi² (10) = 232.39, p < .001). Eighty percent of patients from the "high abstinence/high adherence" group were relapse-free at two year follow-up. This percentage decreased to 24.3 % in the "moderate abstinence/moderate adherence" group.

CONCLUSIONS

Research has shown adherence and abstinence indicators to be useful for identifying subgroups of patients with different prognoses regarding long-term success. Recognizing the sociodemographic and consumption variables associated with these profiles at the beginning of treatment could help to inform the design of more individualized interventions.

Patterns and contexts of polysubstance use among young and older adults who are involved in the criminal legal system and use opioids: A mixed methods study

INTRODUCTION

Opioid prevention and treatment programs tailored to young adults involved in the criminal legal system are rare. We examined profiles of polysubstance use among younger and older adults involved in the criminal legal system who use opioids, and explored their experiences and motivations related to substance use. Information gleaned can inform the adaptation of existing programs and the development of novel approaches for young adults in the criminal legal system.

METHODS

Using a sequential mixed methods design we 1) quantitatively identified typologies of polysubstance users among adults aged 18-24 (n = 92) and those age 25 and over (n = 27) involved in the criminal legal system who use opioids, using latent class analysis and 2) qualitatively explored differences in personal motivations, cultural influences, and psychosocial contexts of substance use by class.

RESULTS

Our quantitative results supported a three-class typology: the majority of participants were in Class I (73 %, n = 87) and reported using primarily alcohol and marijuana. Participants in Classes II (15 %, n = 18) and III (12 %, n = 14) endorsed distinct and complicated polysubstance use profiles. Further, participants in Classes I and III were significantly younger than those in Class II. Qualitative analysis allowed us to understand associations between patterns of use, motivations, and contexts among young and older adults, comparing across classes.

CONCLUSIONS

Our results highlight the importance of attending to the needs of subpopulations based on age and use patterns to adapt and develop targeted treatment and prevention programs for high-risk adults involved in the criminal legal system.

A Scoping Review of Gender, Sex and Sexuality Differences in Polysubstance Use in Adolescents and Adults

BACKGROUND

Polysubstance use is a common, problematic behavior that increases risk of harm to self and others. Research suggests that rates may vary based on gender, sex and sexuality. Understanding the current state of this literature may inform prevention and treatment of polysubstance use, leading to reduced public health burden.

OBJECTIVES

This review aimed to synthesize research on gender, sex and sexuality differences in polysubstance use in adults and adolescents.

METHODS

A scoping review was conducted using all EBSCO databases, PubMed and Google Scholar to identify articles examining the effects of gender, sex and sexuality on polysubstance use. Polysubstance use was defined broadly as the use of any combination of substances over any time period and included licit (alcohol, tobacco) and illicit substances, concurrent and simultaneous use, from lifetime to daily use and use at any frequency. Studies were considered if they were published in peer-reviewed journals between January 1990 and October 2020 and were written in English. Publicly available data sources were also utilized to fully capture prevalence data that has not been published elsewhere.

RESULTS

Findings were mostly inconsistent and often conflicting. Only two findings were generally consistent: adult men were overall more likely to report polysubstance use than adult women, and sexual and gender minorities report more frequent polysubstance use than non-minorities.

CONCLUSIONS

Research has been unable to clearly elucidate differences in polysubstance use prevalence and patterns according to gender, sex and sexuality. Several recommendations are offered to advance future research and address limitations of current research.

Investigating and addressing the immediate and long-term consequences of the COVID-19 pandemic on patients with substance use disorders: a scoping review and evidence map protocol

INTRODUCTION

The COVID-19 pandemic has driven unprecedented social and economic reform in efforts to curb the impact of disease. Governments worldwide have legislated non-essential service shutdowns and adapted essential service provision in order to minimise face-to-face contact. We anticipate major consequences resulting from such policies, with marginalised populations expected to bear the greatest burden of such measures, especially those with substance use disorders (SUDs).

METHODS AND ANALYSIS

We aim to conduct (1) a scoping review to summarise the available evidence evaluating the impact of the COVID-19 pandemic on patients with SUDs, and (2) an evidence map to visually plot and categorise the current available evidence evaluating the impact of COVID-19 on patients with SUDs to identify gaps in addressing high-risk populations.

ETHICS AND DISSEMINATION

Ethics approval is not required for this scoping review as we plan to review publicly available data. This is part of a multistep project, whereby we intend to use the findings generated from this review in combination with data from an ongoing prospective cohort study our team is leading, encompassing over 2000 patients with SUDs receiving medication-assisted therapy in Ontario prior to and during the COVID-19 pandemic.

Impact of Cluster B Personality Disorders in Drugs Therapeutic Community Treatment Outcomes: A Study Based on Real World Data

BACKGROUND

The impact of dual pathology on treatment outcomes is unclear, with the literature reporting both favorable and unfavorable evidence. The main aim of this study was to determine how dual pathology affects treatment outcomes using real world data obtained from inpatients that began treatment in therapeutic communities.

METHOD

The data of 2458 inpatients were used. Clinical information was obtained from electronic medical records. Reliability of diagnosis was checked and revealed a mean kappa value of 0.88.

RESULTS

Of the sample, 41.8% were discharged after achieving the therapeutic objectives. Patients diagnosed with Cluster B personality disorders were found to have a higher risk of dropping out of treatment (HR = 1.320; z = 2.61; p = 0.009).

CONCLUSIONS

Personality traits exhibited by Cluster B patients can interfere with treatment in therapeutic communities. There is a need to develop specific interventions for these inpatient groups, which could be implemented in therapeutic communities.

Comparing re-hospitalisation rates in a real-world naturalistic 24-month follow-up of psychotic patients with different treatment strategies: Oral versus LAI antipsychotics

AIM & BACKGROUND

Non-adherence to antipsychotic treatment is a major issue in the management of severe psychiatric disorders, because it is usually related to future relapses and re-hospitalisations. Long-Acting-Injection (LAI) antipsychotics can be useful to increase treatment adherence in these patients. The aim of the present study was to compare the re-hospitalisation rates of psychotic patients discharged from a psychiatric ward and then, divided into three groups upon the treatment received: LAI antipsychotic, oral antipsychotic at home or oral antipsychotic administered daily by psychiatric nurse staff as patients lived in a long-term care facility.

METHODS

Data on all inpatients consecutively admitted to the Psychiatric Unit of the Nuovo Ospedale Apuano (Massa, Italy), between January 2017 and December 2018, were obtained by the registration record system. Information about eventual re-hospitalisations of these patients, occurred within a 24-month timeframe since discharge, were collected from the same database.

RESULTS

In a Kaplan-Meyer analysis, patients treated with LAI antipsychotics showed significantly lower re-hospitalisation rates in the first 24 months after discharge than those treated with oral ones.

CONCLUSIONS

This study highlights the impact of LAI antipsychotics in preventing re-hospitalisation in severe psychotic patients at high risk in a naturalistic setting. The benefits appear relevant also with respect to a controlled long-term oral antipsychotic treatment, however, further studies are needed to develop more tailored intervention strategies in such complex psychiatric population.

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.

Polysubstance Use Patterns among Justice-Involved Individuals Who Use Opioids

AIM

The current study explores pre-incarceration polysubstance use patterns among a justice-involved population who use opioids. Design: Setting: Data from prison and jail substance use programing in the state of Kentucky from 2015-2017 was examined. Participants: A cohort of 6,569 individuals who reported both pre-incarceration use of opioids and reported the use of more than one substance per day. Measurements: To determine the different typologies of polysubstance use involving opioids, latent profile analysis of the pre-incarceration thirty-day drug use of eight substances was conducted. Multinomial logistic regression predicted latent profile membership. Findings: Six unique profiles of polysubstance use involving opioids and other substances were found; Primarily Alcohol (9.4%), Primarily Heroin (19.0%), Less Polysubstance Use (34.3%), Tranquilizer Polysubstance Use (16.3%), Primarily Buprenorphine (7.8%), and Stimulant-Opioid (13.2%). Profiles differed by rural/urban geography, injection drug use, physical, and mental health symptoms. Conclusion: Findings indicate the heterogeneity of opioid use among a justice-involved population. More diverse polysubstance patterns may serve as a proxy to identifying individuals with competing physical and mental health needs. Future interventions could be tailored to polysubstance patterns during the period of justice-involvement.

Characteristics and Correlates of Psychiatric Problems in Wives of Men with Substance-related Disorders, Kermanshah, Iran

Objectives

We sought to evaluate the characteristics and correlates of psychiatric problems in the wives of men with substance-related disorders.

Methods

Four-hundred and fifty women whose husbands had substance-related disorders were selected by purposive sampling for inclusion in the study.

Results

The prevalence of psychiatric symptoms in our sample was 67.1% (n = 302). Depression was the most prevalent symptom 
(n = 63) and the least was psychosis (n = 5). The prevalence of psychiatric symptoms was highest (26.0%) among women with opiate-dependent spouses (n = 117), and those with hallucinogen-dependent spouses had the lowest prevalence (4.2%). We found a significant relationship between the prevalence of psychiatric disorders and demographic factors including age, women's education, spouse's education, women's job, duration of marriage, number of children, monthly income, and history of psychiatric disorders with the exception of spouses' jobs.

Conclusions

There is a high prevalence of psychiatric symptoms among the wives of men with substance-related disorders and there is need to devise mechanism to reduce the high prevalence of psychiatric disorders.

Modified cognitive behavioral therapy (M-CBT) for cocaine dependence: Development of treatment for cognitively impaired users and results from a Stage 1 trial

Cognitive impairments are associated with poor outcomes when treating cocaine dependent patients, but behavioral interventions to mitigate this impact have not been developed. In this Stage 1A/1B treatment development study, several compensatory strategies (e.g., content repetition, daily logs, diaries, visual presentation) were combined to create a modified cognitive behavioral therapy (M-CBT) for treating cocaine dependence. Initially, a select group of therapists, neuropsychology experts, and patients were asked to provide input on early drafts of the treatment manual and companion patient workbook. After an uncontrolled small trial (N = 15) and two rounds of manual development (Stage 1A), a pilot randomized clinical trial (N = 102) of cocaine dependent outpatients with and without cognitive impairments was conducted (Stage 1B). Participants were randomized to M-CBT (N = 52) or CBT (N = 50). Both treatments were individually delivered over 12 weeks with assessments conducted at baseline, end-of-treatment, and 3-month follow-up. The primary outcome was frequency of cocaine use, measured by number of days used in the prior 7 days. Participants in the two treatment groups did not differ significantly on drug use reduction or retention in treatment. However, among participants who completed at least 9 weeks of treatment, those in M-CBT showed a trend toward greater reduction in cocaine use compared to those in the CBT group. M-CBT is feasible for impaired and nonimpaired cocaine dependent participants. However, M-CBT treatment did not show significant superiority over standard CBT in the present sample. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Satisfaction and burden of mental health personnel: data from healthcare services for substance users and their families

Objective:

To evaluate satisfaction and burden of mental health personnel providing mental health services for substance users and their families.

Method:

Five hundred twenty-seven mental health workers who provide treatment for substance users in five Brazilian states were interviewed. Data on sociodemographic characteristics and measures of satisfaction (SATIS-BR) and burden of mental health personnel (IMPACTO-BR) were collected.

Results:

Type of mental health service and educational attainment were associated with degree of satisfaction and burden. Therapeutic community workers and those with a primary education level reported being more satisfied with the treatment offered to patients, their engagement in service activities, and working conditions. Workers from psychosocial care centers, psychosocial care centers focused on alcohol and other drugs, and social care referral centers (both general and specialized), as well as workers with a higher education, reported feeling overburdened.

Conclusion:

This study offers important information regarding the relationship of mental health personnel with their work. Care providers within this sample reported an overall high level of job satisfaction, while perceived burden differed by type of service and educational attainment. To our knowledge, this is the first study with a sample of mental health professionals working with substance users across five Brazilian states.

Polysubstance use profiles among electronic dance music party attendees in New York City and their relation to use of new psychoactive substances

BACKGROUND

Electronic Dance Music (EDM) party attendees are often polysubstance users and are at high risk for use of new psychoactive substances (NPS). We sought to identify patterns of use of common illegal drugs among EDM party attendees, sociodemographic correlates, and use of NPS as a function of patterns of use of more common drugs to inform prevention and harm reduction.

METHOD

Using time-space-sampling, 1045 individuals aged 18-40 were surveyed entering EDM parties in New York City. We queried past-year use of common illegal drugs and 98 NPS. We conducted latent class analysis to identify polysubstance use profiles of use of eight common drugs (i.e., ecstasy, ketamine, LSD, mushrooms, powder cocaine, marijuana, amphetamine, benzodiazepines). Relationships between drug classification membership and sociodemographics and use of drugs within six NPS categories were examined.

RESULTS

We identified four profiles of use of common drugs: non-polysubstance use (61.1%), extensive polysubstance use (19.2%), moderate polysubstance use/stimulants (12.8%), and moderate polysubstance use/psychedelics (6.7%). Those in the moderate/psychedelic group were at higher odds of using NPS with psychedelic-type effects (2C, tryptamines, and other "new" psychedelics; Ps<0.05). Extensive polysubstance users were at increased odds of reporting use of 2C drugs, synthetic cathinones ("bath salts"), tryptamines, other new (non-phenethylamine) psychedelics, new dissociatives, and synthetic cannabinoids (Ps<0.05).

CONCLUSION

NPS preference is linked to the profile of use of common drugs among individuals in the EDM scene. Most participants were identified as non-polysubstance users, but findings may help inform preventive and harm reduction interventions among those at risk in this scene.

Differences in the Rates of Drug Polyconsumption and Psychiatric Comorbidity among Patients with Cocaine Use Disorders According to the Mental Health Service

Cocaine continues to be a worldwide public health concern in Europe. To improve prognosis and intervention, it is necessary to understand the characteristics of the patients who depend on the services where they receive care. The objective is to analyze the differences among patients who use cocaine and between ambulatory and residential resources to better adapt treatment. This is a descriptive, observational study of two populations of cocaine users in treatment: the ambulatory therapeutic community (ATC) and the therapeutic community (TC). The PRISM diagnostic interview was used for both groups. An analysis of both populations indicates a high prevalence of cocaine, heroin, cannabis, sedative, psychostimulant, and hallucinogen use disorders in the TC population compared to the ATC. In alcohol use disorder, differences between both mental health services were not observed. The degree of severity of cocaine use disorders (CUD) is greater in the TC population. The prevalence of psychiatric comorbidity is not statistically significant between the two populations, except for primary psychotic disorders, which are more prevalent in the TC population. This difference in the prevalence of psychotic disorders may be related to the high prevalence of cannabis use disorders in TC patients. Differences in the prevalence of substance use disorders, severity of CUD, and psychiatric comorbidity may limit the efficiency of mental health services involved in substance use disorder therapeutics. These results suggest the need for careful and extensive phenotyping of patients to improve intervention and prognosis in a clinical resource-dependent manner.

Impact of alcohol consumption on clinical aspects of gambling disorder

Similarities between gambling disorder and substance use disorders have been extensively described. To date, however, few studies using large clinical samples have been carried out that reliably assess the relationship between different levels of alcohol consumption and gambling disorders. The present study aimed to assess the impact of baseline alcohol consumption levels on the clinical profile in a large sample of treatment-seeking individuals. Nine hundred and fifty-one consecutive outpatients diagnosed with gambling disorder according to DSM-IV criteria were compared after being included in three alcohol consumption groups (low risk, abuse and risk of dependence) based on their total raw scores on the AUDIT questionnaire. Results showed a high prevalence of risk of alcohol dependence in GD patients who were immigrants, unemployed, and had a low level of education. A positive linear trend was also found between alcohol consumption level and the prevalence of other current and life-time comorbid mental disorders, and for the presence of drug abuse. Statistically significant differences were found between the three alcohol consumption groups in terms of the evolution and severity of the gambling disorder, self-directedness personality trait, and levels of general psychopathology, hostility and paranoid ideation. In conclusion, the results showed an association between increased alcohol consumption and greater dysfunction.

Psychiatric comorbidity and severity of dependence on substance users: how it impacts on their health-related quality of life?

OBJECTIVE

The aim of this study was to analyze the impact of psychiatric comorbidity and severity of dependence on health-related quality of life (HRQoL).

METHODS

One hundred and ninety-eight substance use disorder (SUD) patients were recruited from an outpatient center that provides treatment for SUD. The International Personality Disorder Examination Screening Questionnaire (IPDE-SQ), Mini International Neuropsychiatric Interview (MINI), Substance Dependence Severity Scale (SDSS) and Health-Related Quality of Life for Drug Abusers test (HRQoLDA test) were administered.

RESULTS

Patients with psychiatric comorbidity evaluated their HRQoL more negatively than patients without psychiatric comorbidity. An analysis of the relationship between severity of dependence and HRQoL scores indicated significant correlations among alcohol-, cocaine-, heroin- and cannabis-dependent patients. According to multivariate analyses, anxiety disorders, mood disorders, severity of dependence on alcohol, cannabis, cocaine, paranoid, borderline and avoidant personality disorders (PDs) were observed to have a major impact on HRQoL.

CONCLUSIONS

SUD (severity of dependence on alcohol, cannabis and cocaine) and other mental disorders (anxiety disorders; mood disorders; paranoid, borderline and avoidant PDs) are involved in the deterioration of the SUD patients' HRQoL. This study demonstrates the need for integrated treatment for SUD patients. Treating only a part of the problem (whether SUD or other mental disorders are present) is insufficient for improving quality of life.

Dual cannabis and alcohol use disorders in young adults: Problems magnified

BACKGROUND

Alcohol and marijuana are the 2 most commonly used substances among young adults. The present study examines whether having 2 DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th Edition) diagnoses (alcohol and cannabis) is associated with greater problems than having 1 (alcohol or cannabis) diagnosis.

METHODS

Participants were 307 young adults (18-25 years) from the community who met criteria for DSM-5 alcohol use disorder (AUD), cannabis use disorder (CUD), or both (dual use disorder [DUD]). Participants reported alcohol and marijuana use in the past 90 days (Timeline Follow-Back), alcohol problems (Short Inventory of Problems), and marijuana problems (Marijuana Problems Scale).

RESULTS

Eighty-four participants (27.4%) met criteria for AUD, 107 (34.9%) met criteria for CUD, and 116 (37.8%) met criteria for DUD. In multivariate analyses, the DUD group reported greater alcohol use frequency and more alcohol problems than the CUD-only group but not the AUD-only group. However, DUD individuals reported greater drinking intensity than singly diagnosed individuals. Those with DUD reported a greater proportion of marijuana consumption days than the AUD-only group but not the CUD-only group. However, DUD individuals reported more marijuana problems than both singly diagnosed groups.

CONCLUSIONS

Results show that the concurrent presence of both DSM-5 AUD and CUD is associated with heavier drinking patterns and greater marijuana problems than disordered use of either substance alone, thus affirming the magnified severity of alcohol and marijuana use that accompanies dual DSM-5 alcohol and marijuana use disorders.

Cannabis and Psychosis: a Critical Overview of the Relationship

Interest in the relationship between cannabis use and psychosis has increased dramatically in recent years, in part because of concerns related to the growing availability of cannabis and potential risks to health and human functioning. There now exists a plethora of scientific articles addressing this issue, but few provide a clear verdict about the causal nature of the cannabis-psychosis association. Here, we review recent research reports on cannabis and psychosis, giving particular attention to how each report provides evidence relating to two hypotheses: (1) cannabis as a contributing cause and (2) shared vulnerability. Two primary kinds of data are brought to bear on this issue: studies done with schizophrenic patients and studies of first-episode psychosis. Evidence reviewed here suggests that cannabis does not in itself cause a psychosis disorder. Rather, the evidence leads us to conclude that both early use and heavy use of cannabis are more likely in individuals with a vulnerability to psychosis. The role of early and heavy cannabis use as a prodromal sign merits further examination, along with a variety of other problem behaviors (e.g., early or heavy use of cigarettes or alcohol and poor school performance). Future research studies that focus exclusively on the cannabis-psychosis association will therefore be of little value in our quest to better understand psychosis and how and why it occurs.

Strain and cocaine-induced differential opioid gene expression may predispose Lewis but not Fischer rats to escalate cocaine self-administration

The aim of the present study was to investigate alterations in gene expression of opioid system components induced by extended access (18 h) cocaine self-administration and to determine the impact of genetic background in the vulnerability to escalate cocaine intake. Comparing two inbred rat strains, we previously reported that Lewis rats progressively escalated cocaine consumption compared to Fischer rats, in a new translational model of intravenous cocaine self-administration, which included 14 sessions of 18-h operant sessions in which rats were allowed to select the cocaine unit dose to self-administer. We compare here Fischer and Lewis rats in the gene expression of endogenous opioid peptides (Pomc, Penk, Pdyn) and cognate receptors (Oprm, Oprk and Oprd) in reward-related brain regions, after exposure to either cocaine self-administration or yoked-saline, in the aforementioned translational paradigm. We performed a correlation analysis between the mRNA level, found in the Dorsal Striatum (DS), Nucleus accumbens (NAcc) shell and core respectively, and individual cocaine intake. Our findings show that the gene expression of all the aforementioned opioid genes exhibit strain-dependent differences in the DS, in absence of cocaine exposure. Also, different strain-specific cocaine-induced mRNA expression of Oprm and Oprk was found in DS. Only few differences were found in the ventral parts of the striatum. Moreover, gene expression level of Pdyn, Penk, Oprk, and Oprm in the DS was significantly correlated with cocaine intake only in Fischer rats. Overall, these data shed light on potential genetic differences which may predispose of subjects to initiate and escalate cocaine consumption.