Abuse and dependence on prescription opioids in adults: a mixture categorical and dimensional approach to diagnostic classification

Opioid use disorder (OUD) and treatment for opioid problems among OUD symptom subtypes in individuals misusing opioids

Background

In 2021, approximately 60 million individuals worldwide and 9 million individuals in the United States (US) reported opioid misuse. In the US, 2.5 million have OUD, of which only about a third receive any substance abuse treatment. OUD is often regarded as a monolithic disorder but different opioid problem subtypes may exist beyond DSM-IV/5 criteria. Understanding the characteristics of these subtypes could be useful for informing treatment and intervention strategies.

Methods

Latent class analysis was used to identify OUD symptom subtypes among persons in the US who reported misusing prescription opioids or heroin in the 2015-2018 National Survey on Drug Use and Health (n=10,928). Regression analyses were utilized to determine associations between class membership and treatment receipt, as well as demographic characteristics and other comorbid conditions.

Results

Five classes were identified with unique OUD symptom patterns: Class 1: Asymptomatic (71.6%), Class 2: Tolerance/Time (14.5%), Class 3: Loss of Control/Pharmacological (LOC/Pharmacol) (5.7%), Class 4: Social Impairment (2.6%), and Class 5: Pervasive (5.6%). Nearly all persons in the LOC/Pharmacol, Social Impairment, and Pervasive classes met criteria for OUD (98-100%); however, they differed in receipt of past-year treatment for substance use (28%, 28%, 49%, respectively). Age, race, education, insurance status, and criminal activity were also associated with treatment receipt.

Conclusions

There were considerable differences in OUD symptom patterns and substance use treatment among individuals who misused opioids. The findings indicate a substantial unmet need for OUD treatment and point to patterns of heterogeneity within OUD that can inform development of treatment programs.

Female-male differences in prescription pain reliever dependence levels: Evidence on newly incident adolescent and young adult users in the United States, 2002-2014

BACKGROUND

A comprehensive epidemiology of dependence on prescription opioid pain relievers requires evidence about age-specific female-male differences, possibly manifest during adolescent and early adult years. In this study, we identified newly incident extra-medical users of prescription pain relievers (EMPPR), all observed with onsets before the 22nd birthday. We then quantified female-male differences in clinical features or manifestations of opioid dependence (OD), devised a measurement-equivalent OD dimension, and estimated age-specific female-male differences in OD levels.

METHOD

The population under study included 12-to-21-year-old non-institutionalized civilian community residents of United States sampled for recent nation-scale surveys. Confidential computer-assisted self-interviews identified newly incident EMPPR users (n = 10,188). Analysis-weighted estimation procedures yielded cumulative incidence proportions for each OD feature, evaluated measurement non-equivalence across subgroups, and estimated female-male differences age-by-age.

RESULTS

(1) Tolerance and salience ('spending a lot of time') are most common OD features. (2) Measurement non-equivalence (bias) was found across sex- and onset-age groups. (3) With biasing features removed, we can see elevated OD levels for female new initiates, age-by-age. Subsidiary analyses suggested possibly accelerated progression toward higher OD levels when extra-medical PPR use starts before age 18.

CONCLUSIONS

Dimensional approaches to OD and other drug use disorders have gained popularity but can be fragile when differential measurement biases are left uncontrolled. This study's bias-corrected dimensional view of female-male differences shows elevated OD levels among newly incident female EMPPR users relative to new male initiates. Future studies can check for accelerated progression to higher OD levels when EM use starts before age 18 years.

Opioid-related hospitalizations in Pennsylvania: A latent class analysis

BACKGROUND

Opioid abuse is associated with substantial morbidity and often results in hospitalization. Despite this, patient-level factors associated with opioid-related hospitalizations are not well understood.

METHODS

We used the Pennsylvania Health Care Cost Containment Council dataset (2000-2014) to identify opioid-related hospitalizations using primary and/or secondary ICD-9-CM hospital discharge codes for opioid use disorder (OUD), opioid poisoning, and heroin poisoning. Latent class analyses (LCA) of patient-level factors including sociodemographic characteristics, pregnancy, alcohol, tobacco, other substance use, and psychiatric disorders were used to identify common patterns within hospitalizations.

RESULTS

Among 28,538,499 hospitalizations, 430,569 (1.5%) were opioid-related. LCA identified five latent class (LC) patient groups associated with opioid-related hospitalizations: pregnant women with OUD (LC1); women over 65 with opioid overdose (LC2); OUD, polysubstance use and co-occurring psychiatric disorders (LC3); patients with opioid overdose without co-occurring polysubstance use (LC4); and African American patients with OUD and co-occurring cocaine use (LC5). LC3 was the largest latent class (58.2%) with annual hospitalizations doubling over time.

DISCUSSION

Among patients with opioid-related discharges, we identified five subpopulations among this sample. These findings suggest increased outpatient OUD treatment, mental health service support for patients with co-occurring psychiatric disorders and polysubstance use to prevent overdose and hospitalization.

Prevalence and patterns of opioid misuse and opioid use disorder among primary care patients who use tobacco

BACKGROUND

Current data suggest that opioid misuse or opioid use disorder (OUD) may be over represented among tobacco users. However, this association remains understudied in primary care settings. A better understanding of the extent of heterogeneity in opioid misuse among primary care patients who use tobacco may have implications for improved primary care-based screening, prevention, and intervention approaches.

METHODS

Data were derived from a sample of 2000 adult (aged ≥18) primary care patients across 5 distinct clinics. Among past-year tobacco users (n = 882), we assessed the prevalence of opioid misuse and OUD by sociodemographic characteristics and past-year polysubstance use. Latent class analysis (LCA) was used to identify heterogeneous subgroups of tobacco users according to past-year polysubstance use patterns. Multinomial logistic regression was used to examine variables associated with LCA-defined class membership.

RESULTS

Past-year tobacco use was reported by >84% of participants who reported past-year opioid misuse or OUD. Among those reporting past-year tobacco use, the prevalence of past-year opioid misuse and OUD was 14.0% and 9.5%, respectively. The prevalence of opioid misuse or OUD was highest among tobacco users who were male or unemployed. Three LCA-defined classes among tobacco users were identified including a tobacco-minimal drug use group (78.0%), a tobacco-cannabis use group (10.1%), and a tobacco-opioid/polydrug use group (11.9%). Class membership differed by sociodemographic characteristics.

CONCLUSIONS

Results from this study support the benefit of more comprehensive assessment of and/or monitoring for opioid misuse among primary care patients who use tobacco, particularly for those who are male, unemployed, or polydrug users.

Determining the Initiation of Opiate Misuse Resulting in Opioid Use Disorder in Pregnant Women

The aim of this study was to explore the "opiate misuse footprint" made by obstetrics and gynecology physicians in prescribing opioid medications for postpartum pain control that led to opioid misuse and opioid use disorder. Data were collected using intake information and anonymous surveys administered to pregnant women at local methadone clinics in Indianapolis, Indiana, in 2016-2017. Results from this study revealed that 40% of the 33 participants stated that the first drug they became addicted to was prescription opioids; 71% stated that the first opiate they became addicted to was a prescription pain medication. Prescription opioids were mainly obtained from emergency medicine physicians and friends. Reported use of opioids within the past four months was high, with the most commonly used drugs being methadone (57.6%) and heroin (42.4%). A majority of participants also endorsed a history of sexual and physical abuse, recent incarceration, and mental health disorders. As a large number of pregnant women with opioid use disorder reported their initial drug of misuse as prescription pain medications, it is important to avoid overprescribing opioids in reproductive-age women.

The use of latent variable mixture models to identify invariant items in test construction

Purpose

Patient-reported outcome measures (PROMs) are frequently used in heterogeneous patient populations. PROM scores may lead to biased inferences when sources of heterogeneity (e.g., gender, ethnicity, and social factors) are ignored. Latent variable mixture models (LVMMs) can be used to examine measurement invariance (MI) when sources of heterogeneity in the population are not known a priori. The goal of this article is to discuss the use of LVMMs to identify invariant items within the context of test construction.

Methods

The Draper-Lindely-de Finetti (DLD) framework for the measurement of latent variables provides a theoretical context for the use of LVMMs to identify the most invariant items in test construction. In an expository analysis using 39 items measuring daily activities, LVMMs were conducted to compare 1- and 2-class item response theory models (IRT). If the 2-class model had better fit, item-level logistic regression differential item functioning (DIF) analyses were conducted to identify items that were not invariant. These items were removed and LVMMs and DIF testing repeated until all remaining items showed MI.

Results

The 39 items had an essentially unidimensional measurement structure. However, a 1-class IRT model resulted in many statistically significant bivariate residuals, indicating suboptimal fit due to remaining local dependence. A 2-class LVMM had better fit. Through subsequent rounds of LVMMs and DIF testing, nine items were identified as being most invariant.

Conclusions

The DLD framework and the use of LVMMs have significant potential for advancing theoretical developments and research on item selection and the development of PROMs for heterogeneous populations.

Treatment utilization among persons with opioid use disorder in the United States

BACKGROUND

The United States is experiencing an opioid overdose epidemic. Treatment use data from diverse racial/ethnic groups with opioid use disorder (OUD) are needed to inform treatment expansion efforts.

METHODS

We examined demographic characteristics and behavioral health of persons aged ≥12 years that met criteria for past-year OUD (n=6,125) in the 2005-2013 National Surveys on Drug Use and Health (N=503,101). We determined the prevalence and correlates of past-year use of alcohol/drug use treatment and opioid-specific treatment to inform efforts for improving OUD treatment.

RESULTS

Among persons with OUD, 81.93% had prescription (Rx) OUD only, 9.75% had heroin use disorder (HUD) only, and 8.32% had Rx OUD+HUD. Persons with Rx OUD+HUD tended to be white, adults aged 18-49, males, or uninsured. The majority (80.09%) of persons with OUD had another substance use disorder (SUD), and major depressive episode (MDE) was common (28.74%). Of persons with OUD, 26.19% used any alcohol or drug use treatment, and 19.44% used opioid-specific treatment. Adolescents, the uninsured, blacks, native-Hawaiians/Pacific-Islanders/Asian-Americans, persons with Rx OUD only, and persons without MDE or SUD particularly underutilized opioid-specific treatment. Among alcohol/drug use treatment users, self-help group and outpatient rehabilitation treatment were commonly used services.

CONCLUSIONS

Most people with OUD report no use of OUD treatment. Multifaceted interventions, including efforts to access insurance coverage, are required to change attitudes and knowledge towards addiction treatment in order to develop a supportive culture and infrastructure to enable treatment-seeking. Outreach efforts could target adolescents, minority groups, and the uninsured to improve access to treatment.

Exploring the latent trait of opioid use disorder criteria among frequent nonmedical prescription opioid users

BACKGROUND

There is a need to explore the dimensional and categorical phenotypes of criteria of opioid use disorder among frequent nonmedical users of prescription opioids (NMUPO) users.

METHODS

We used pooled data of 2011-2012 National Survey on Drug Use and Health to examine reliability and phenotypic variability in the diagnosis of OUD secondary to NMUPO in a nationally-representative sample of 18+ years-old frequent past-year NMUPO users (120+ days, n = 806). Through exploratory factor analysis (EFA) and latent class analysis (LCA), we examined 10 past-year OUD criteria. We examined associations between the latent classes and sociodemographic/psychiatric/NMUPO correlates.

RESULTS

OUD criteria were unidimensional, and a three-class model was the overall best fitting solution for characterizing individuals into phenotypes along this unidimensional continuum: a "non-symptomatic class" (40.7%), "Tolerance-Time spent class" (29.0%) with high probability of endorsing Tolerance/Time Spent criteria, and a "High-moderate symptomatic class" (30.1%). The last class was significantly associated with being male, having insurance and obtaining prescription opioids (PO) nonmedically via "doctor shopping" as compared to the non-symptomatic class. "Tolerance-Time spent class" was significantly associated with being younger (18-25 years) and obtaining PO nonmedically from family/friends as compared to the non-symptomatic class.

CONCLUSION

This study revealed the different characteristics and routes of access to PO of different classes of frequent NMUPO users. It is possible that these groups may respond to different interventions, however such conclusions would require a clinical study.

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.

A Pilot Study To Define Chemical Coping in Cancer Patients Using the Delphi Method

BACKGROUND

"Chemical coping" is a commonly used term in the pain and palliative care literature, but is heterogeneously defined. We conducted a Delphi survey among palliative care and pain specialists internationally to identify a consensus definition for "chemical coping with opioids" and warning signs for chemical coping.

METHODS

This Delphi survey consisted of two rounds on the following: (1) concepts and definition related to chemical coping, (2) warning signs for chemical coping, and (3) demographics. Consensus in this study was defined as agreement by a minimum of 70% of the experts.

RESULTS

Participating in the first round were 14/19 (74%) physicians; 12/14 (86%) participated in the second round. The international experts reached the following consensus definition for chemical coping with opioids (92% agreement): "The use of opioids to cope with emotional distress, characterized by inappropriate and/or excessive opioid use." They also identified depression (consensus 93%); psychiatric disease (86%); a history of substance abuse (86%); a positive score for the Cut-down, Annoyed, Guilty, and Eye-opener (CAGE) alcoholism screening test (79%); a history of alcoholism (79%); and a history of smoking (71%) as important warning signs for chemical coping.

CONCLUSION

Our expert panel reached a consensus definition for chemical coping and related warning signs, which may help clinicians and researchers to identify patients at risk of opioid misuse.

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.

Les troubles liés à l’utilisation des opioïdes prescrits médicalement

Épidémiologie Au cours des 10 à 15 dernières années, le Canada est devenu le deuxième plus grand consommateur d’opioïdes de prescription (OP), principalement pour le traitement de la douleur. Cette augmentation a été plus marquée chez les 55 ans et plus. Même si personne ne conteste le droit des patients à recevoir des traitements adéquats pour la douleur, il n’en demeure pas moins que cette disponibilité accrue a entraîné son lot de problèmes : augmentation des visites à l’urgence et des décès liés aux opioïdes ainsi que du trouble lié à l’utilisation (TLU) des opioïdes, trouble qui est d’ailleurs associé à une prévalence accrue, de l’ordre de 40 %, de divers problèmes psychiatriques, dont les troubles dépressifs majeurs.

Neuroscience De nouvelles connaissances issues des neurosciences nous permettent de mieux comprendre la réaction du cerveau lors de l’exposition à ces substances et le caractère chronique du TLU des opioïdes. Quoique historiquement perçu comme une faiblesse de caractère ou un vice, le TLU des opioïdes est maintenant reconnu comme une condition chronique résultant d’une interaction complexe entre une substance, des facteurs d’environnement et un génotype individuel. Malheureusement, ces évidences scientifiques ne sont pas encore largement appliquées à la clinique et la majorité des médecins n’ont pas les habiletés nécessaires pour diagnostiquer et traiter le TLU des opioïdes.

Guides de pratique clinique Des recommandations et guides de pratique peuvent nous aider à identifier les personnes plus vulnérables à un mésusage, et à mieux encadrer la prescription et la gestion de la médication. Il ne s’agit pas de se désintéresser de ces patients et de les abandonner à leur sort mais plutôt de leur offrir des soins inspirés des meilleures pratiques et appuyés sur des évidences scientifiques de qualité.

Depressive symptoms among adolescents and older adults in Mexico City

PURPOSE

Determine the structure of depressive symptoms among adolescents and older adults through the person-centered approach of latent class analysis (LCA).

METHODS

The study is based on data from two independent samples collected in Mexico City (2,444 adolescents and 2,223 older adults) which included the revised version of the CES-D. The presence or absence of depressed mood (dysphoria), diminished pleasure (anhedonia), drastic change in weight, sleep problems, thinking and concentration difficulties, excessive or inappropriate guilt, fatigue, psychomotor agitation/retardation, and suicide ideation were used in LCA to determine the structure of depressive symptoms for adolescents and older adults.

RESULTS

Adolescents reported higher excessive or inappropriate guilt compared to older adults, while older adults had higher proportions of anhedonia, sleep problems, fatigue, and psychomotor agitation/retardation. Similar proportions were found in other symptoms. The LCA analysis showed the best fit with four latent classes (LC): LC 1, "symptoms suggestive of major depressive episode (MDE)" with prevalence of 5.9 % (n = 144) and 10.3 % (n = 230) among adolescents and older adults, respectively; LC 2, "probable MDE symptoms" 18.2 % (n = 446) and 23.0 % (n = 512); LC 3, "possible MDE" 27.7 % (n = 676) and 21.8 % (n = 485); LC 4, "without significant depressive symptoms" 48.2 % (n = 1,178) and 44.8 % (n = 996). The differences in item thresholds between the two groups (adolescents vs. older adults) were statistically significant (Wald test = 255.684, df = 1, p < 0.001).

CONCLUSIONS

This study documented important similarities and differences in the structure of depressive symptoms between adolescents and older adults that merit acknowledgment, further study, and consideration of their potential clinical and public health implications.

Towards the characterization and validation of alcohol use disorder subtypes: integrating consumption and symptom data

BACKGROUND

There is evidence that measures of alcohol consumption, dependence and abuse are valid indicators of qualitatively different subtypes of alcohol involvement yet also fall along a continuum. The present study attempts to resolve the extent to which variations in alcohol involvement reflect a difference in kind versus a difference in degree.

METHOD

Data were taken from the 2001-2002 National Epidemiologic Survey of Alcohol and Related Conditions. The sample (51% male; 72% white/non-Hispanic) included respondents reporting past 12-month drinking at both waves (wave 1: n = 33644; wave 2: n = 25186). We compared factor mixture models (FMMs), a hybrid of common factor analysis (FA) and latent class analysis (LCA), against FA and LCA models using past 12-month alcohol use disorder (AUD) criteria and five indicators of alcohol consumption reflecting frequency and heaviness of drinking.

RESULTS

Model comparison revealed that the best-fitting model at wave 1 was a one-factor four-class FMM, with classes primarily varying across dependence and consumption indices. The model was replicated using wave 2 data, and validated against AUD and dependence diagnoses. Class stability from waves 1 to 2 was moderate, with greatest agreement for the infrequent drinking class. Within-class associations in the underlying latent factor also revealed modest agreement over time.

CONCLUSIONS

There is evidence that alcohol involvement can be considered both categorical and continuous, with responses reduced to four patterns that quantitatively vary along a single dimension. Nosologists may consider hybrid approaches involving groups that vary in pattern of consumption and dependence symptomatology as well as variation of severity within group.

DSM-5 criteria for substance use disorders: recommendations and rationale

Since DSM-IV was published in 1994, its approach to substance use disorders has come under scrutiny. Strengths were identified (notably, reliability and validity of dependence), but concerns have also arisen. The DSM-5 Substance-Related Disorders Work Group considered these issues and recommended revisions for DSM-5. General concerns included whether to retain the division into two main disorders (dependence and abuse), whether substance use disorder criteria should be added or removed, and whether an appropriate substance use disorder severity indicator could be identified. Specific issues included possible addition of withdrawal syndromes for several substances, alignment of nicotine criteria with those for other substances, addition of biomarkers, and inclusion of nonsubstance, behavioral addictions.This article presents the major issues and evidence considered by the work group, which included literature reviews and extensive new data analyses. The work group recommendations for DSM-5 revisions included combining abuse and dependence criteria into a single substance use disorder based on consistent findings from over 200,000 study participants, dropping legal problems and adding craving as criteria, adding cannabis and caffeine withdrawal syndromes, aligning tobacco use disorder criteria with other substance use disorders, and moving gambling disorders to the chapter formerly reserved for substance-related disorders. The proposed changes overcome many problems, while further studies will be needed to address issues for which less data were available.

Measuring Outcome in the Treatment of Cocaine Dependence

BACKGROUND

Little in known about the extent to which outcome measures used in studies of the treatment of cocaine dependence are associated with longer-term use and with broader measures of clinical improvement. The current study examined reductions in use, and abstinence-oriented measures, in relation to functioning and longer-term clinical benefits in the treatment of cocaine dependence.

METHODS

Overall drug use, cocaine use, and functioning in a number of addiction-related domains for 487 patients diagnosed with DSM-IV cocaine dependence and treated with one of four psychosocial interventions in the NIDA Cocaine Collaborative Treatment Study were assessed monthly during 6 months of treatment and at 9, 12, 15, and 18 month follow-up.

RESULTS

Measures of during-treatment reduction in use were moderately correlated with drug and cocaine use measures 12 months, but showed non-significant or small correlations with measures of functioning at 12 months. Highest correlations were evident for abstinence measures (maximum consecutive days abstinence and completely abstinent) during treatment in relation to sustained (3 month) abstinence at 12 months. Latent class analysis of patterns of change over time revealed that most patients initially (months 1 to 4 of treatment) either became abstinent immediately or continued to use every month. Over the couse of follow-up, patients either maintained abstinence or used regularly - intermittent use was less common.

CONCLUSIONS

There were generally small associations between various measures of cocaine use and longer-term clinical benefits, other than abstinence was associated with continued abstinence. No one method of measuring outcome of treatment of cocaine dependence appears superior to others.

Extramedical use of prescription pain relievers by youth aged 12 to 21 years in the United States: national estimates by age and by year

OBJECTIVE To identify when youth are most likely to start using prescription pain relievers to get high or for other unapproved indications outside the boundaries of what a prescribing physician might intend (ie, extramedical use). DESIGN Cross-sectional surveys of adolescent cohorts, 2004 to 2008. SETTING The United States. PARTICIPANTS Large nationally representative samples of youth in the United States who had been assessed for the 2004 through 2008 National Survey on Drug Use and Health, yielding data from 138 729 participants aged 12 to 21 years. MAIN OUTCOME MEASURES Estimated age-specific risk of starting extramedical use of prescription pain relievers, year by year, and confirmation of age at peak risk by tracing the experience of individual cohorts during this period. RESULTS The estimated peak risk of starting extramedical use of prescription pain relievers occurs in midadolescence, well before the college years. The age at peak risk is 16 years, when an estimated 2% to 3% become newly incident users. Smaller risk estimates are observed at age 12 to 14 years and at age 19 to 21 years. CONCLUSIONS For initiatives to prevent youth from using prescription pain relievers to get high or for other unapproved indications, a focus on the last year of high school and the post-secondary school years may be too little too late. Practice-based approaches are needed in addition to public health interventions based on effective alcohol and tobacco prevention programs during the earlier adolescent years.

Are the symptoms of cannabis use disorder best accounted for by dimensional, categorical, or factor mixture models? A comparison of male and female young adults

Despite the consensus that criteria for cannabis abuse and dependence and symptoms of withdrawal are best explained by a single latent liability, it remains unknown whether alternative models provide a better explanation of these criteria. A series of latent factor, latent class, and hybrid factor mixture models were fitted to data from 872 recent cannabis users from the Minnesota Twin Family Study who completed Diagnostic and Statistical Manual of Mental Disorders (3rd ed., revised, and 4th ed.) diagnostic criteria for cannabis abuse, dependence, and symptoms of withdrawal. Despite theoretical appeal, results did not support latent class or factor mixture modeling. Instead, symptoms of abuse, dependence, and withdrawal were better summarized by a single latent factor Cannabis Use Disorder (CUD) for male and female young adults. An almost 2-fold sex difference in item endorsement was best explained by a single mean difference on the CUD factor, indicating that young men have a greater latent liability toward expressing CUD.

Exploring age of onset as a causal link between major depression and nonmedical use of prescription medications

BACKGROUND

Nonmedical use of prescription medications (NUPM) has been associated with major depression (MDD), but the specific processes by which they might interact and influence one another are understudied. This investigation attempted to clarify the relationship between MDD and NUPM by examining whether age of MDD onset influenced current and past NUPM and by examining whether age of NUPM onset influenced lifetime or past year MDD.

METHODS

These goals were met through use of data from the 2005 to 2007 National Survey on Drug Use and Health. Analyses utilized design-based logistic regression, and current age and order of MDD onset and NUPM initiation were examined in interactions with age of MDD or NUPM onset.

RESULTS

For each year MDD onset was delayed, odds of lifetime, past year, past 30-day NUPM and substance dependence from NUPM were decreased by 2.3%, 2.6%, 1.9% and 2.3%, respectively. Earlier NUPM onset increased odds of past year (3.8%) and lifetime MDD (4.3%) in young adults, and lifetime MDD (2.5%) in 26-34 age group. Current age also interacted with age of MDD onset, with effects on NUPM pronounced in the 65 and older cohort. Order of MDD/NUPM onset generally did not interact with age of MDD onset, but it did interact with age of NUPM onset; the effects of NUPM onset on past year MDD were only significant in those with NUPM first.

CONCLUSIONS

These results highlight the need for further investigations of the interactions between depression and NUPM, particularly to evaluate potential causal relationships.

Assessing the dimensionality of lifetime DSM-IV alcohol use disorders and a quantity-frequency alcohol use criterion in the Australian population: a factor mixture modelling approach

AIMS

With the revision of the DSM-IV underway, two important research issues currently dominate the addiction literature: (a) how can the dimensionality of DSM-IV alcohol use disorders (AUD) diagnostic criteria best be described? and (ii) should a quantity-frequency alcohol use (QF) criterion be added to the existing diagnostic criteria set in the DSM-V? The current study addressed these aims by analysing lifetime data from a recent Australian population survey.

METHODS

Data from adults screened for lifetime DSM-IV AUD in the 2007 National Survey on Mental Health and Wellbeing (NSMHWB) were analysed (n = 5409). A series of alternative factor analytic, latent class and factor mixture or 'hybrid' models were used to assess the dimensionality of lifetime DSM-IV AUD diagnostic criteria and a lifetime QF criterion.

RESULTS

Examination of the goodness-of-fit indices revealed that a one-factor or a two-factor model, a three-class latent class model or a two-factor zero-class hybrid model, were all acceptable models for the data. A simple structure one-factor model was considered to be the most parsimonious and theoretically meaningful model, given the high correlation between the abuse and dependence factors (0.874) in the two-factor model. The inclusion of the QF criterion did not enhance the fit of the one-factor model.

CONCLUSIONS

Incorporating both dimensional and categorical conceptions of lifetime AUD did not provide substantial gains over a simple structure unidimensional model of AUD severity. The utility of a QF use criterion in helping to diagnose AUD is questionable. These findings should be of relevance to the DSM-5 substance use disorder workgroup.