Subtyping of substance use disorders in a high-risk welfare-to-work sample: A latent class analysis

Predictors of substance use disorder treatment and mutual support group participation among Black women across the criminal legal spectrum: A latent class approach

BACKGROUND

The purpose of this study includes: 1) identifying classes of substance-related needs among Black women, and 2) examining the effect of substance-related need classes and culturally-relevant factors on Black women's use of substance use disorder (SUD) treatment and mutual support groups.

METHODS

As part of a longitudinal cohort study, Black women were recruited in prison nearing release, on probation, and in the community without involvement in the criminal legal system (CLS, n=565) and followed-up at 18-months. We conducted a baseline latent class analysis of substance-related needs among Black women. Logistic regression models adjusted for culturally-relevant factors to predict the use of treatment and frequency of mutual support group participation over 18-months among Black women who use drugs.

RESULTS

Four classes by level of needs were found: low, daily marijuana use, high mental health, and high comorbidity. During the 18-month follow-up, women characterized by the high comorbidity need class and with higher scores of religious well-being were more likely to frequently participate in mutual support groups. Non-CLS-involved women were less likely to engage with both treatment and mutual support groups than women from the prison sample at 18-months.

CONCLUSIONS

This study highlights four distinct classes of substance-related needs among Black women, highlighting the complex patterns of behavior and within-racial group differences among Black women. Black women with high comorbidity needs were more likely to participate in mutual support groups, but the latent classes did not predict SUD treatment indicating other non-medical and social contextual need factors may be at play.

Patterns of Polydrug Use Classes Among a Subset of Latino Male Seasonal Workers in South Florida: A Latent Class Analysis

BACKGROUND

Little is known about polydrug use among Latino seasonal farmworkers. This cross-sectional study with male Latino seasonal workers (LSWs) living in South Florida categorized distinct classes of drug use and then characterized each drug use typology by demographic, structural, and psychological factors.

METHODS

One hundred and twenty-five male LSWs were recruited during community events using convenience sampling between July 2019-March 2020. Latent class analysis was conducted by leveraging measures of self-reported use of nine drugs in the past year (sedatives, cannabis, stimulants, heroin, opioids, cocaine, PCP, hallucinogens, and inhalants). Correlates of latent class membership were examined using 3-step categorical latent variable logistic regression. Analyses were performed using Mplus version 8 and SAS 9.4.

RESULTS

Four drug use classes were identified, male LSWs who exhibited: 1) use of illegal opioids only (n = 32); 2) concurrent cannabis and cocaine use (n = 75); 3) concurrent sedative and cannabis use (n = 13); and 4) high concurrent drug use (n = 5). About 84.7% of the sample reported use of at least one drug in the past 12 months. LSWs who identified as White and were married or in a stable relationship were likely to only use illegal opioids. LSWs with less than high school education and self-reported good to excellent health were more likely to use cannabis and cocaine. Men with moderate to severe anxiety and self-reported bad health were classified as engaging in sedative and cannabis co-use. Survivors of physical abuse were more commonly classified as people using high concurrent substances relative to non-abused men among the four classes.

CONCLUSIONS

This pilot study suggests the presence of heterogeneity in polydrug use classes among LSWs in South Florida.

Patterns of polysubstance use and clinical comorbidity among persons seeking substance use treatment: An observational study

INTRODUCTION

Polysubstance use is common among individuals seeking treatment for substance use disorders (SUD). However, we know less about patterns and correlates of polysubstance use among treatment-seeking populations. The current study aimed to identify latent patterns of polysubstance use and associated risk factors in persons entering SUD treatment.

METHODS

Patients (N = 28,526) being admitted for substance use treatment reported on their use of thirteen substances (e.g., alcohol, cannabis, cocaine, amphetamines, methamphetamines, other stimulants, heroin, other opioids, benzodiazepines, inhalants, synthetics, hallucinogens, and club drugs) in the month before treatment and prior to the month before treatment. Latent class analysis (LCA) determined the relationship between class membership and gender, age, employment status, unstable housing, self-harm, overdose, past treatment, depression, generalized anxiety disorder, and/or post-traumatic stress disorder (PTSD).

RESULTS

Identified classes included: 1) Alcohol primary, 2) Moderate probability of past-month alcohol, cannabis, and/or opioid use; 3) Alcohol primary, Lifetime cannabis and cocaine use; 4) Opioid primary, Lifetime use of alcohol, cannabis, hallucinogens, club drugs, amphetamines, and cocaine; 5) Moderate probability of past-month alcohol, cannabis, and/or opioid use, Lifetime use of various substances; 6) Alcohol and cannabis primary, Lifetime use of various substances; and 7) High past-month polysubstance use. Individuals who engaged in past-month polysubstance use attended to face elevated risk of screening positive for recent unstable housing, unemployment, depression, anxiety, PTSD, self-harm, and overdose.

CONCLUSIONS

Current polysubstance use is associated with significant clinical complexity. Tailored treatments that reduce harms resulting from polysubstance use and related psychiatric comorbidity may improve treatment outcomes in this population.

A scoping review of electroencephalographic (EEG) markers for tracking neurophysiological changes and predicting outcomes in substance use disorder treatment

Substance use disorders (SUDs) constitute a growing global health crisis, yet many limitations and challenges exist in SUD treatment research, including the lack of objective brain-based markers for tracking treatment outcomes. Electroencephalography (EEG) is a neurophysiological technique for measuring brain activity, and although much is known about EEG activity in acute and chronic substance use, knowledge regarding EEG in relation to abstinence and treatment outcomes is sparse. We performed a scoping review of longitudinal and pre-post treatment EEG studies that explored putative changes in brain function associated with abstinence and/or treatment in individuals with SUD. Following PRISMA guidelines, we identified studies published between January 2000 and March 2022 from online databases. Search keywords included EEG, addictive substances (e.g., alcohol, cocaine, methamphetamine), and treatment related terms (e.g., abstinence, relapse). Selected studies used EEG at least at one time point as a predictor of abstinence or other treatment-related outcomes; or examined pre- vs. post-SUD intervention (brain stimulation, pharmacological, behavioral) EEG effects. Studies were also rated on the risk of bias and quality using validated instruments. Forty-four studies met the inclusion criteria. More consistent findings included lower oddball P3 and higher resting beta at baseline predicting negative outcomes, and abstinence-mediated longitudinal decrease in cue-elicited P3 amplitude and resting beta power. Other findings included abstinence or treatment-related changes in late positive potential (LPP) and N2 amplitudes, as well as in delta and theta power. Existing studies were heterogeneous and limited in terms of specific substances of interest, brief times for follow-ups, and inconsistent or sparse results. Encouragingly, in this limited but maturing literature, many studies demonstrated partial associations of EEG markers with abstinence, treatment outcomes, or pre-post treatment-effects. Studies were generally of good quality in terms of risk of bias. More EEG studies are warranted to better understand abstinence- or treatment-mediated neural changes or to predict SUD treatment outcomes. Future research can benefit from prospective large-sample cohorts and the use of standardized methods such as task batteries. EEG markers elucidating the temporal dynamics of changes in brain function related to abstinence and/or treatment may enable evidence-based planning for more effective and targeted treatments, potentially pre-empting relapse or minimizing negative lifespan effects of SUD.

Profiles of individuals with cannabis-related disorders

Background: Profiles of individuals with cannabis-related disorders (CRD) in specialized addiction treatment centers serving high-need patients have not been identified. This longitudinal study developed a typology for 9,836 individuals with CRD attending Quebec (Canada) addiction treatment centers in 2012-2013. Methods: Data on sociodemographic, clinical and service use variables were extracted from several databases for the years 1996-1997 to 2014-2015. Individual profiles were produced using Latent Class Analysis and compared predicting health outcomes on emergency department (ED) use, hospitalizations and suicidal behaviors for 2015-2016. Results: Six profiles were identified: 1-Older individuals, many living in couples and working, with moderate health problems, receiving intensive general practitioner (GP) care and high continuity of physician care; 2-Older individuals with chronic CRD, multiple social and health problems, and low health service use (chronic CRD referred to experiencing CRD for several years; social problems related to homelessness, unemployment, having criminal records or living alone); 3-Students with few social and health problems, and low health service use; 4-Young adults, many working, with few health problems, least health service use and continuity of physician care; 5-Youth, many working but some criminal offenders, with 1 or 2 years of CRD, few health problems and high addiction treatment center use; and 6-Older individuals with chronic CRD and multiple social and health problems, high health service use and continuity of physician care. Profiles 6 and 2 had the worst health outcomes. Conclusions: For Profiles 2 to 5, outreach and motivational services should be prioritized, integrated health and criminal justice services for profile 5 and, for Profiles 2 and 6, assertive community treatments. Screening, brief intervention and referrals to addiction treatment centers may also be encouraged for individuals with CRD, particularly those in Profile 2. This cohort had high social and health needs relative to services received, suggesting continued need for care.

Tina's ParTy line: Polysubstance use patterns in sexual minority men living with HIV who use methamphetamine

INTRODUCTION

This cross-sectional study examined the associations of demographic, structural and psychological factors with distinct typologies of polysubstance use in sexual minority men (SMM) living with HIV who use methamphetamine.

METHODS

In total, 161 SMM living with HIV who reported methamphetamine use in the past 3 months were recruited in San Francisco from 2013 to 2017 for a randomised controlled trial. A latent class analysis was conducted by leveraging baseline measures of self-reported use of 15 substances in the past 3 months as well as validated screening measures of hazardous alcohol and cannabis use. Correlates of latent class membership were examined using a three-step categorical latent variable logistic regression.

RESULTS

Four typologies of substance use were identified: (i) methamphetamine use only (43%); (ii) methamphetamine and crack-cocaine use (22%); (iii) party and play use-methamphetamine, gamma-hydroxybutyrate and amyl nitrites (i.e. poppers) with erectile dysfunction drugs (31%); and (iv) high polysubstance use (4%). SMM of colour and those with a history of incarceration were more commonly classified as engaging in methamphetamine and crack-cocaine use compared to party and play use. Men with higher sexual compulsivity scores were more commonly classified as engaging in party and play use and polysubstance use.

DISCUSSION AND CONCLUSIONS

There is substantial heterogeneity in polysubstance use patterns among SMM living with HIV who use methamphetamine. This will inform the development of tailored substance use interventions addressing the unique needs of SMM of colour and targeting sexual compulsivity as a prominent comorbidity for some men.

Profiles of trauma histories as predictors of depression among women living with HIV

This study examined co-occurring psychosocial problems among 120 women living with HIV (WLWH) in Washington, DC, USA. Participants completed a demographic survey, PHQ-9 (depressive symptoms), the Life Stressor Checklist (stressful events) and the PCL-C (PTSD symptoms in civilian populations). We calculated descriptive statistics and chi-square solutions for participant demographics. Classes of trauma history were established using latent class analysis (LCA). Latent indicators were extracted from participant self-reported traumatic histories on the LSC-R. Traumatic events have been found to be predictive of both depression. Latent class solution selection was guided by utility in evaluating and discriminating between classes as predictors of scales measuring depression or trauma exposure. Three distinct classes of trauma histories were identified: a high trauma (HT) class, an abuse/neglect (AN) class and a childhood trauma (CT) class. Binary logistic regression analyses determined whether trauma profiles predicted depression or PTSD after controlling for age, marital status, race and education. Participants in both the AN and CT class were over five times more likely than those in the HT class to endorse depressive symptoms. Classes differed significantly on whether they endorse depressive symptoms (p = .008) and marital status (p = .009), while PTSD appeared to trend toward significance (p = .085).

Clinical symptoms and personality traits predict subpopulations of treatment-seeking substance users

BACKGROUND

The heterogeneity of treatment-seeking substance users represents a challenge, as most studies include participants having problems with specific substances or merge polysubstance users into the same category without considering differences between profiles. Considering the inconsistent literature on predictors of treatment outcomes, this study aimed to identify subpopulations of individuals with substance use disorders (SUDs) and analyze the association among class membership, previous relapses, and treatment retention.

METHODS

The study recruited a total of 159 participants (mean age = 40.60, SD = 8.70; 85.5% males) from two treatment facilities (outpatient daycare and inpatient residential centers). The baseline assessment gathered lifetime and current substance use, and personality and psychopathology measures. The study performed a latent class analysis to identify subpopulations of substance users and explored predictors of class membership using a multinomial regression analysis.

RESULTS

The study found six different classes of substance users based on their diagnosis and pattern of substance use: class 1 (6.92% of participants): individuals with cannabis as primary substance, alcohol/cocaine as secondary substance and additional use of stimulants or other drugs; class 2 (30.82%): cocaine as primary substance, alcohol as secondary and additional cannabis use; class 3 (20.13%): alcohol as primary substance, cocaine as secondary and additional cannabis use; class 4 (17.61%): cocaine as primary substance, cannabis as secondary and additional alcohol/other drugs use; class 5 (16.35%): alcohol as primary and cannabis as secondary substance; class 6 (8.18%): heroin as primary substance, cocaine as secondary and additional alcohol use. Several traits and clinical symptoms predicted distinct class memberships. Participants pertaining to class 6 presented the highest number of relapses (M = 2.54, SD = 1.56).

CONCLUSIONS

These results have several clinical implications. Belonging to class 6 was associated with a greater number of previous relapses. Also, specific psychopathological symptoms and personality traits may impact SUD treatment response, which may help clinicians to guide initial assessment and treatment allocation.

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.

Latent Classes of Polydrug Users as a Predictor of Crash Involvement and Alcohol Consumption

OBJECTIVE

Polydrug users have been shown to be at higher risk for alcohol consumption and crash involvement. However, research has shown that polydrug groups differ in some important ways. It is currently unknown how polydrug-using groups differ in terms of crash involvement and alcohol consumption.

METHOD

The current study used latent class analysis to examine subgroups of polydrug users (n = 384) among a sample of drivers in Virginia Beach, Virginia (N = 10,512). A series of logistic regression analyses were conducted to determine the relationship between polydrug use categories and crash involvement and alcohol consumption.

RESULTS

Four distinct subclasses of users were identified among polydrug-using drivers: Class 1 is the "marijuana-amphetamines class" and accounts for 21.6% of polydrug users. Class 2 is the "benzo-antidepressant class" and accounts for 39.0% of polydrug users. Class 3 is the "opioid-benzo class" and accounts for 32.7% of polydrug users. Finally, Class 4 is the "marijuana-cocaine class" and accounts for 6.7% of the study sample. Drivers in the opioid-benzo class were significantly more likely than those in any other class as well as non-drug users and single-drug users to be involved in a crash and were more likely than those in most other conditions to consume alcohol. No significant difference was found between marijuana-amphetamine users or benzo-antidepressant users and non-drug users on crash risk.

CONCLUSIONS

Some polydrug users are indeed at greater risk for crash involvement and alcohol consumption; however, not all polydrug users are significantly worse than single-drug users and/or non-drug users, and the practice of lumping polydrug users together when predicting crash risk runs the risk of inaccurately attributing crash involvement to certain drivers.

A latent class analysis of the past-30-day substance use patterns among lifetime cocaine users: Findings from a community sample in North Central Florida

Objectives

Cocaine use is increasing and many cocaine users engage in polysubstance use. Within polysubstance use, relationships among use of individual substances are necessarily complex. To address this complexity, we used latent class analysis (LCA) to identify patterns of polysubstance use among lifetime cocaine users and examine associations among these patterns, demographics, and risk profiles.

Methods

Members of HealthStreet, an ongoing community engagement program, were asked about lifetime and past 30-day use of cocaine, alcohol, tobacco, marijuana, and prescription medications, mental health conditions, recent Emergency Department (ED) visits and demographics. LCA was used to identify classes of past 30-day polysubstance use among individuals who endorsed lifetime cocaine use. Multinomial logistic regression identified factors associated with these classes.

Results

Among 1797 lifetime cocaine users, a five-class LCA model was identified: 1) past 30-day tobacco use only (45%), 2) past 30-day alcohol, marijuana and tobacco use (31%), 3) past 30-day tobacco, prescription opioid and sedative use (13%), 4) past 30-day cocaine, alcohol, marijuana and tobacco use (9%), 5) past 30-day cocaine and multiple polysubstance use (2%). Demographics, ED visits and mental health conditions were associated with class membership.

Conclusions

Approximately 11% of lifetime cocaine users used cocaine in the past 30 days with two different concurrent substance use patterns. Prescription medication (opioids and sedatives) and complex polysubstance use patterns were stronger indicators of negative outcomes than current cocaine use. Cocaine was not used frequently with other stimulants. In addition to polysubstance use, prescription medication use should be targeted for intervention among lifetime cocaine users.

Examining racial/ethnic differences in patterns of benzodiazepine prescription and misuse

BACKGROUND

Benzodiazepines (BZDs) are widely prescribed during psychiatric treatment. Unfortunately, their misuse has led to recent surges in overdose emergency visits and drug-related deaths.

METHODS

Electronic health record data from a large healthcare system were used to describe racial/ethnic, sex, and age differences in BZD use and dependence. Among patients with a BZD prescription, we assessed differences in the likelihood of subsequently receiving a BZD dependence diagnosis, number of BZD prescriptions, receiving only one BZD prescription, and receiving 18 or more BZD prescriptions. We also estimated multivariate hazard models and generalized linear models, assessing racial/ethnic differences after adjustment for covariates.

RESULTS

In both unadjusted and adjusted analyses, Whites were more likely than Blacks, Hispanics, and Asians to have a BZD dependence diagnosis and to receive a BZD prescription. Racial/ethnic minority groups received fewer BZD prescriptions, were more likely to have only one BZD prescription, and were less likely to have 18 or more BZD prescriptions. We identified greater BZD misuse among older patients but no sex differences.

CONCLUSIONS

Findings from this study add to the emerging evidence of high relative rates of prescription drug abuse among Whites. There is a concern, given their greater likelihood of having only one BZD prescription, that Blacks, Hispanics, and Asians may be discontinuing BZDs before their clinical need is resolved. Research is needed on provider readiness to offer racial/ethnic minorities BZDs when indicated, patient preferences for BZDs, and whether lower prescription rates among racial/ethnic minorities offer protection against the progression from prescription to addiction.

The costs of crime associated with stimulant use in a Canadian setting

BACKGROUND

Costs attributable to criminal activity are a major component of the economic burden of substance use disorders, yet there is a paucity of empirical evidence on this topic. Our aim was to estimate the costs of crime associated with different forms and intensities of stimulant use.

METHODS

Retrospective cohort study, including individuals from three prospective cohorts in Vancouver, Canada, measured biannually (2011-2015), reporting stimulant use at baseline assessment. Monthly crime costs included policing, court, corrections, and criminal victimization (2016 CAD). We estimated monthly crime costs associated with mutually exclusive categories of crack, cocaine, methamphetamine, and polystimulant use, stratified by daily/non-daily use, relative to stimulant abstinence, as well as the independent effects of treatment (opioid agonist (OAT) and other addiction treatment). We used a two-part model, capturing the probability of criminal activity and costs of crime with generalized linear logistic and gamma regression models, respectively, controlling for age, gender, education, homelessness, mental health issues, employment, prior incarceration, alcohol and opioid use.

RESULTS

The study sample included 1599 individuals (median age 39, 65.9% male) assessed over 5299 biannual interviews. Estimates of associated monthly crime costs ranged from $5449 [95% C.I.: $2180, $8719] for non-daily polystimulant use, to $8893 [$4196, $13,589] for daily polystimulant use. Cost differences between daily/non-daily use, injection/non-injection, and stimulant type were not statistically significant. Drug treatment was not associated with lower monthly crime costs in our sample.

CONCLUSIONS

Substantial crime-related costs were associated with stimulant use, emphasizing the urgency for development and implementation of efficacious treatment regimens.

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.

Genetics of Tinnitus: An Emerging Area for Molecular Diagnosis and Drug Development

Subjective tinnitus is the perception of sound in the absence of external or bodily-generated sounds. Chronic tinnitus is a highly prevalent condition affecting over 70 million people in Europe. A wide variety of comorbidities, including hearing loss, psychiatric disorders, neurodegenerative disorders, and temporomandibular joint (TMJ) dysfunction, have been suggested to contribute to the onset or progression of tinnitus; however, the precise molecular mechanisms of tinnitus are not well understood and the contribution of genetic and epigenetic factors remains unknown. Human genetic studies could enable the identification of novel molecular therapeutic targets, possibly leading to the development of novel pharmaceutical therapeutics. In this article, we briefly discuss the available evidence for a role of genetics in tinnitus and consider potential hurdles in designing genetic studies for tinnitus. Since multiple diseases have tinnitus as a symptom and the supporting genetic evidence is sparse, we propose various strategies to investigate the genetic underpinnings of tinnitus, first by showing evidence of heritability using concordance studies in twins, and second by improving patient selection according to phenotype and/or etiology in order to control potential biases and optimize genetic data output. The increased knowledge resulting from this endeavor could ultimately improve the drug development process and lead to the preventive or curative treatment of tinnitus.

Marijuana and Other Substance Use Among Motor Vehicle Operators: A Latent Class Analysis

OBJECTIVE

The deleterious effect of multiple-substance use on driving performance is well established, but relatively little research has examined the patterns of drug use among multiple-substance users and its relationship to both alcohol use and adverse driving outcomes.

METHOD

The current study used latent class analysis to examine subgroups of substance users among a population of drivers who screened positively for 2 or more of 13 substances other than alcohol (N = 250). A series of logistic regression analyses was conducted to examine demographic predictors of latent class assignment and class association with adverse driving outcomes.

RESULTS

Four distinct subclasses of users were identified among multiple-substance-using drivers: Class 1 consisted of individuals who demonstrated high levels of all substances indicators (5%). The second class demonstrated high levels of marijuana and cocaine use and lower levels of all other substances (27%). The third class screened high for marijuana and nonmedical prescription opiate analgesics use (36%), whereas the last class demonstrated high nonmedical prescription opiate analgesics and benzodiazepine use (32%). Drivers in Class 2 (marijuana and cocaine users) were more likely to be younger and have a positive breath alcohol concentration than drivers in any other class.

CONCLUSIONS

Because multidrug users show dissimilar characteristics, the propensity of researchers to lump all multiple-substance users together may either erroneously attribute the potentially profound impact of those in the marijuana and cocaine use class to all multiple-substance users or dilute their specific contribution to crash risk.

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

BACKGROUND

Therapeutic community (TC) clients frequently display a pattern of multiple substance use disorders (SUDs) which is associated with poorer treatment outcomes. This study aimed to characterize multiple SUD profiles in patients enrolled in TCs, and examine the association of these profiles with social, medical and psychiatric outcomes.

METHODS

Observational study. We acquired substance use diagnoses and sociodemographic, medical and psychiatric comorbidity data for 4102 patients who had been admitted to six public TCs in Andalusia (Spain) from 2004 to 2012. Latent class analysis was applied to participants' substance use diagnoses, and the resulting classes were associated with social (i.e., education, employment, criminality), medical (i.e., infectious diseases) and psychiatric comorbidity.

RESULTS

We found four differentiated profiles of substance use diagnoses among TC patients: cocaine/opiates (Class 1: 37% of participants); cocaine/opiates/benzodiazepines (Class 2: 25.3%); alcohol (Class 3: 24.7%); and cocaine/cannabis/alcohol (Class 4: 12.9%). Classes 1 and 2 were associated with poorer social and medical characteristics. Class 2 was also associated with greater prevalence of impulsive spectrum mental disorders. Class 3 was associated with greater prevalence of mood and anxiety disorders and cognitive dysfunction, and Class 4 was associated with higher prevalence of psychotic illness.

CONCLUSIONS

Patients admitted to TCs have heterogeneous substance use diagnostic profiles. Profiles involving multiple use of heroin, cocaine, alcohol and benzodiazepines are associated with poorer social and medical function and impulse control disorders. Profiles involving alcohol use and cannabis/cocaine use are associated with cognitive dysfunction and psychotic illness respectively.

Multi-view singular value decomposition for disease subtyping and genetic associations

BACKGROUND

Accurate classification of patients with a complex disease into subtypes has important implications for medicine and healthcare. Using more homogeneous disease subtypes in genetic association analysis will facilitate the detection of new genetic variants that are not detectible using the non-differentiated disease phenotype. Subtype differentiation can also improve diagnostic classification, which can in turn inform clinical decision making and treatment matching. Currently, the most sophisticated methods for disease subtyping perform cluster analysis using patients' clinical features. Without guidance from genetic information, the resultant subtypes are likely to be suboptimal and efforts at genetic association may fail.

RESULTS

We propose a multi-view matrix decomposition approach that integrates clinical features with genetic markers to detect confirmatory evidence for a disease subtype. This approach groups patients into clusters that are consistent between the clinical and genetic dimensions of data; it simultaneously identifies the clinical features that define the subtype and the genotypes associated with the subtype. A simulation study validated the proposed approach, showing that it identified hypothesized subtypes and associated features. In comparison to the latest biclustering and multi-view data analytics using real-life disease data, the proposed approach identified clinical subtypes of a disease that differed from each other more significantly in the genetic markers, thus demonstrating the superior performance of the proposed approach.

CONCLUSIONS

The proposed algorithm is an effective and superior alternative to the disease subtyping methods employed to date. Integration of phenotypic features with genetic markers in the subtyping analysis is a promising approach to identify concurrently disease subtypes and their genetic associations.

Latent class analysis of polysubstance use, sexual risk behaviors, and infectious disease among South African drug users

BACKGROUND

HIV transmission risk among non-injection drug users is high due to the co-occurrence of drug use and sexual risk behaviors. The purpose of the current study was to identify patterns of drug use among polysubstance users within a high HIV prevalence population.

METHODS

The study sample included 409 substance users from the Pretoria region of South Africa. Substances used by 20% or more the sample included: cigarettes, alcohol, marijuana and heroin in combination, marijuana and cigarettes in combination, and crack cocaine. Latent class analysis was used to identify patterns of polysubstance use based on types of drugs used. Multivariate logistic regression analyses compared classes on demographics, sexual risk behavior, and disease status.

RESULTS

Four classes of substance use were found: MJ+Cig (40.8%), MJ+Her (30.8%), Crack (24.7%), and Low Use (3.7%). The MJ+Cig class was 6.7 times more likely to use alcohol and 3 times more likely to use drugs before/during sex with steady partners than the Crack class. The MJ+Cig class was 16 times more likely to use alcohol before/during sex with steady partners than the MJ+Her class. The Crack class was 6.1 times more likely to engage in transactional sex and less likely to use drugs before/during steady sex than the MJ+Her class.

CONCLUSIONS

Findings illustrate patterns of drug use among a polysubstance using population that differ in sexual risk behavior. Intervention strategies should address substance use, particularly smoking as a route of administration (ROA), and sexual risk behaviors that best fit this high-risk population.

A latent class analysis of drug abuse in a national Swedish sample

BACKGROUND

Drug abuse (DA) is a clinically heterogeneous syndrome. Using medical, legal, death and pharmacy records covering the entire population of Sweden, could we uncover meaningful subtypes of DA?

METHOD

We performed a latent class analysis (LCA) on all individuals in Sweden born 1950–1993 who were registered with DA or its consequences (n=192,501) and then validated these classes using demographics, patterns of co-morbidity with alcohol use disorder (AUD), non-DA crime and psychiatric illness, and the pattern of aggregation and co-aggregation in sibling pairs.

RESULTS

The best-fit LCA had six classes : (1) low-frequency pure criminal, (2) high-frequency medical criminal, (3) low-frequency pure medical, (4) high-frequency medical, (5) prescription and (6) death. Each class had a distinct pattern of demographic features and co-morbidity and aggregated within sibling pairs with at least moderate specificity. For example, class 2 was characterized by early age at registration, low educational attainment, high male preponderance, high rates of AUDs, strong resemblance within sibling pairs [odds ratio (OR) 12.6] and crime and the highest risk for DA in siblings (20.0%). By contrast, class 5 had a female preponderance, late age at registration, low rates of crime and AUDs, high rates of psychiatric illness, high familiality within sibling pairs (OR 14.7) but the lowest observed risk for DA in siblings (8.9%).

CONCLUSIONS

DA as assessed by public records is a heterogeneous syndrome. Familial factors contribute substantially to this heterogeneity. Advances in our understanding of etiological processes leading to DA will be aided by a consideration of this heterogeneity.

Types of polydrug use among Spanish adolescents

OBJECTIVE

This study examined the types of polydrug use among Spanish adolescents.

METHOD

1501 high school students (50.6% female) aged 12 to 17years old (mean age=14.03, SD=1.28), from public schools in the city of Girona (Catalonia, Spain), completed the survey.

RESULTS

In the previous six months 20.9% of the Spanish adolescents used alcohol, 18.8% tobacco, 10.5% cannabis and 0.7% cocaine. Specifically, 28.6% of the sample (n=429; 29% males and 28.2% females) used at least one drug and 13.9% reported polydrug use (n=208; 12.6% males and 15.1% females). The present research also found that the most critical ages for starting polydrug use were 14 and 15years old. More than one quarter (27.9%) of the adolescent polydrug users were type A (tobacco and alcohol), 67.8% were type B (cannabis together with tobacco and/or alcohol) and 3.4% were type C (cannabis together with tobacco and/or alcohol, and cocaine).

CONCLUSIONS

These results suggest that Spanish adolescents, particularly males, commence polydrug use at an earlier age than other European adolescents. Early preventative strategies and a multisubstance perspective are greatly needed in Spain to avoid the initiation of polydrug use or to prevent progress onto heavier drugs.