Patterns and motivations of polysubstance use: a rapid review of the qualitative evidence

Substance use patterns, quantities, and associated risk factors in women with polysubstance misuse

Polysubstance use (PSU), the use of two or more substances proximally, is highly prevalent and has amplified the risk for morbidity and mortality. However, PSU patterns and associated risk factors are not well characterized. This may be especially relevant to women who are known to be vulnerable to stress/trauma, craving, pain, and anxious and depressive symptoms as associated risk factors for PSU. A cross-sectional observational study was conducted to characterize substance use patterns in women who regularly used cocaine, opioids, marijuana, alcohol, benzodiazepines and/or nicotine and were being assessed for a placebo-controlled study of guanfacine treatment (n = 94; ages 19-65). Data on stress/traumatic life events, drug cravings for each substance, pain ratings, and anxiety and depressive symptoms were also obtained using standardized well-validated surveys. High use per day of two or more drugs was observed (72.7% ± 33.3%) and opioid amounts were high relative to other drug amounts (p's < 0.001). Notably, higher stress/trauma events and higher cravings are each associated with cumulative PSU days, amounts and probability of an individual PSU day (p's < 0.02). This remained when PSU versus single substance use was compared. Pain, anxiety and depressive symptoms were not associated with PSU metrics. These findings characterize specific patterns of PSU in women and show that average drug craving and stress/trauma events are associated with PSU. Interventions that focus on stress/trauma and craving management could be of benefit in reducing PSU risk in women.

Motivation and context of concurrent stimulant and opioid use among persons who use drugs in the rural United States: a multi-site qualitative inquiry

BACKGROUND

In recent years, stimulant use has increased among persons who use opioids in the rural U.S., leading to high rates of overdose and death. We sought to understand motivations and contexts for stimulant use among persons who use opioids in a large, geographically diverse sample of persons who use drugs (PWUD) in the rural settings.

METHODS

We conducted semi-structured individual interviews with PWUD at 8 U.S. sites spanning 10 states and 65 counties. Content areas included general substance use, injection drug use, changes in drug use, and harm reduction practices. We used an iterative open-coding process to comprehensively itemize and categorize content shared by participants related to concurrent use.

RESULTS

We interviewed 349 PWUD (64% male, mean age 36). Of those discussing current use of stimulants in the context of opioid use (n = 137, 39%), the stimulant most used was methamphetamine (78%) followed by cocaine/crack (26%). Motivations for co-use included: 1) change in drug markets and cost considerations; 2) recreational goals, e.g., seeking stronger effects after heightened opioid tolerance; 3) practical goals, such as a desire to balance or alleviate the effects of the other drug, including the use of stimulants to avoid/reverse opioid overdose, and/or control symptoms of opioid withdrawal; and 4) functional goals, such as being simultaneously energized and pain-free in order to remain productive for employment.

CONCLUSION

In a rural U.S. cohort of PWUD, use of both stimulants and opioids was highly prevalent. Reasons for dual use found in the rural context compared to urban studies included changes in drug availability, functional/productivity goals, and the use of methamphetamine to offset opioid overdose. Education efforts and harm reduction services and treatment, such as access to naloxone, fentanyl test strips, and accessible drug treatment for combined opioid and stimulant use, are urgently needed in the rural U.S. to reduce overdose and other adverse outcomes.

Longitudinal patterns of use of stimulants and opioids in the AIDS linked to the IntraVenous experience cohort, 2005-2019

BACKGROUND

Overdoses involving opioids and stimulants are on the rise, yet few studies have examined longitudinal trends in use of both substances. We sought to describe use and co-use of opioids and stimulants, 2005-2019, in the AIDS Linked to the Intravenous Experience (ALIVE) cohort - a community-based cohort of people with a history of injection drug use living in or near Baltimore, MD.

METHODS

We included 2083 ALIVE participants, who had at least two visits during the study period. Our outcome was based on self-reported use of opioids and stimulants in the prior 6 months. We estimated prevalence of 4 categories of use (neither stimulants nor opioids, only stimulants, only opioids, stimulants and opioids), using a non-parametric multi-state model, accounting for the competing event of death and weighting for informative loss to follow-up. All analyses were stratified by enrollment cohort, with the main analysis including participants who enrolled prior to 2015 and a sub-analysis including participants who enrolled 2015-2018.

RESULTS

In the main analysis, prevalence of using stimulants and opioids decreased from 38 % in 2005 to 12 % 2013 but stabilized from 2014 onwards (13-19 %). The prevalence of using only stimulants (7-11 %) and only opioids (5-10 %) was stable across time. Participants who reported using both were more likely to report homelessness, depression, and other substance use (e.g., marijuana and heavy alcohol use) than participants in the other use categories. On average, 65 % of visits with use of both were followed by a subsequent visit with use of both; of participants transitioning out of using both, 13% transitioned to using neither.

CONCLUSIONS

While use of stimulants and opioids declined in the cohort through 2013, a meaningful proportion of participants persistently used both. More research is needed to understand and develop strategies to mitigate harms associated with persistent use of both stimulants and opioids.

Codeine and promethazine: Exploratory study on "lean" or "sizzurp" using national survey data and an online forum

BACKGROUND

The concoction known as "lean" containing codeine and promethazine, holds a prominent cultural presence and is often referenced in mass media platforms (e.g., music and social media). Surprisingly, there's a scarcity of national data characterizing the use of lean. Therefore, the current study investigated the use of lean using national survey data and online forum participant input, and focused on identifying concurrent substance use, exploring co-administration with other substances (e.g., alcohol, cannabis), and determining lean-related experiences.

METHODS

We analyzed data from the National Survey on Drug Use and Health (NSDUH) spanning 2007-2019, identifying persons who used lean (weighted N = 42,275). Additionally, we conducted a Reddit-based study to gather insights about lean consumtion (N = 192).

RESULTS

The NSDUH data indicated that lean use was most prevalent among teenagers and young adults (ages 13-21), accounting for 66% of the sample. This trend was more pronounced in male respondents (75%) compared to females. Additionally, the use was predominantly observed among Black/African American (29%), Hispanic (28%), and White (33%) populations, with these groups also reporting higher levels of concurrent alcohol and cannabis use. Similarly, findings from Reddit showed that individuals who used lean were predominantly male (67%) and exhibited elevated concurrent rates of alcohol (83%) and cannabis (46%) use in the past 30 days. Moreover, approximately 66% of respondents met criteria for severe lean use disorder, and 37% acknowledged driving under its influence.

CONCLUSION

The NSDUH data found that mostly young adult males reported consuming lean in the past twelve months, though the racial/ethnic breakdown of persons who used lean was diverse. The Reddit data found that most individuals in the sample met the criteria for a substance use disorder pertaining to their lean consumption. These findings underscore the clinical significance and necessity for further controlled research on lean.

Identifying excessive chronic alcohol use with phosphatidylethanol in patients with suspected severe injury-results from the IDART study

INTRODUCTION

Acute and chronic alcohol use are well-known risk factors for accidents and injuries, and concurrent psychoactive drug use can increase injury risk further. Phosphatidylethanol (PEth) 16:0/18:1 is a biomarker used to determine alcohol consumption the previous 3-4 weeks. The aim was to investigate the prevalence of chronic alcohol use in trauma patients, as determined by PEth 16:0/18:1 concentrations, and how excessive chronic alcohol use relate to demographic variables, injury mechanisms and drug use.

SETTING

Patients received at Norwegian trauma hospitals from March 2019 to February 2020. The study is part of the Impairing Drugs and Alcohol as Risk factors for Traumatic Injuries study.

METHODS

All patients aged ≥ 16 years received with trauma team were included in the study. Data on injury date and mechanism, gender and age was registered. Blood samples were analyzed for 22 psychoactive medicinal and illicit drugs, ethanol and phosphatidylethanol 16:0/18:1. Regression analyses were conducted to assess associations between alcohol use and gender, age, injury mechanism and drug use.

RESULTS AND CONCLUSION

Of the 4845 patients included in the study, 10% had PEth 16:0/18:1 concentration ≥ 600 nM (~430 ng/mL), indicative of excessive chronic alcohol use. Being male, between 44-61 years old, involved in violence, and testing positive for medicinal drugs was associated with excessive chronic alcohol use.Excessive chronic alcohol use was common among males, middle-aged, patients with violence as injury mechanism and those with medicinal drug use. These findings emphasize the need to detect and treat excessive chronic alcohol use among trauma patients.

Patterns of polydrug use among Black Americans who misuse opioids

In the United States, opioid-related deaths involving polydrug use are now more prevalent than those involving only opioids. What often goes unnoticed is that deaths involving more than one substance are increasing more rapidly among Black Americans than Whites. Unfortunately, little research attention is paid to understanding opioid-related polydrug use patterns among Black Americans. As a result, less is known regarding which drug combinations are most common among this population and their reasons for co-using certain drugs. Therefore, the objective of this mixed methods study was to identify which substances were most commonly co-used with opioids among Black Americans, while also capturing their motives for combining opioids with other drugs. This study used data from the Florida Minority Health Study, a mixed-methods project that included online surveys (n = 303) and qualitative in-depth interviews (n = 30) of Black Americans who misuse opioids. Data collection was conducted from August 2021 to February 2022 throughout Southwest Florida. Analyses revealed that opioids were most commonly combined with alcohol, cocaine, and methamphetamine, respectively. Opioids were co-used with alcohol in an attempt to enhance the desired effect (i.e., intoxication), while stimulants and opioids were combined to counteract the undesirable side effects of the other. This study begins to answer the question of which/why substances are combined with opioids among Black Americans and should inform behavioral health interventions targeted at this population. Data on this topic are especially timely as the United States goes through the current fourth wave of the opioid crisis that is characterized by deaths due to polydrug use. These findings invite further study using nationally representative data to determine the extent to which polydrug using patterns differ across racial/ethnic groups.

The relationship between substance use and self-reported aspects of social functioning in patients with a psychotic disorder

BACKGROUND

In patients with a psychotic disorder, rates of substance use (tobacco, cannabis, and alcohol) are higher compared to the general population. However, little is known about associations between substance use and self-reported aspects of social functioning in patients with a psychotic disorder.

METHODS

In this cross-sectional study of 281 community-dwelling patients with a psychotic disorder, linear regression models were used to assess associations between substance use (tobacco, cannabis, or alcohol) and self-reported aspects of social functioning (perceived social support, stigmatization, social participation, or loneliness) adjusting for confounders (age, gender, and severity of psychopathology).

RESULTS

Compared to nonsmokers, both intermediate and heavy smokers reported lower scores on loneliness (E = -0.580, SE = 0.258, p = 0.025 and E = -0.547, SE = 0,272, p = 0.046, respectively). Daily cannabis users reported less social participation deficits than non-cannabis users (E = -0.348, SE = 0.145, p = 0.017). Problematic alcohol use was associated with more perceived social support compared to non-alcohol use (E = 3.152, SE = 1.102, p = 0.005). Polysubstance users reported less loneliness compared to no users (E = -0.569, SE = 0.287, p = 0.049).

CONCLUSIONS

Substance use in patients with psychosis is associated with more favorable scores on various self-reported aspects of social functioning.

Are you thinking what I'm thinking? Defining what we mean by "polysubstance use."

The rise in drug overdoses and harms associated with the use of more than one substance has led to increased use of the term "polysubstance use" among researchers, clinicians, and public health officials. However, the term retains no consistent definition across contexts. The current authors convened from disciplines including sociology, epidemiology, neuroscience, and addiction psychiatry to propose a recommended definition of polysubstance use. An iterative process considered authors' formal and informal conversations, insights from relevant symposia, talks, and conferences, as well as their own research and clinical experiences to propose the current definition. Three key concepts were identified as necessary to define polysubstance use: (1) substances involved, (2) timing, and (3) intent. Substances involved include clarifying either (1) the number and type of substances used, (2) presence of more than one substance use disorder, or (3) primary and secondary substance use. The concept of timing is recommended to use clear terms such as simultaneous, sequential, and same-day polysubstance use to describe short-term behaviors (e.g., 30-day windows). Finally, the concept of intent refers to clarifying unintentional use or exposure when possible, and greater attention to motivations of polysubstance use. These three components should be clearly defined in research on polysubstance use to improve consistency across disciplines. Consistent definitions of polysubstance use can aid in the synthesis of evidence to better address an overdose crisis that increasingly involves multiple substances.

Trends and psychosocial correlates of same day polysubstance use among people who inject drugs in Australia, 2012-2022

BACKGROUND

Polysubstance use is associated with negative health and social outcomes among people who inject drugs. We aimed to describe trends in polysubstance use and identify psychosocial correlates and associated drug use risk behaviours. We defined polysubstance use as intentional same day use of more than one of three drug classes: opioids, other non-opioid depressants (hereafter 'depressants'), and stimulants.

METHODS

We used 10 years (2012-2022, excluding 2020) of data from annual surveys in Australian capital cities with people who inject drugs (N=5657) to construct five mutually exclusive polysubstance use profiles: opioid-depressant, opioid-stimulant, stimulant-depressant, opioid-stimulant-depressant, and single drug class use. We examined time trends using the Mann Kendall test and identified correlates using multinomial logistic regression.

RESULTS

Same day polysubstance use was relatively common among this sample (43.6%). Opioid-depressant use was the most frequent polysubstance use profile, but this decreased over the study period (32.6% to 13.3%, p<0.001). This aligned with observed decreases in use of pharmaceutical opioids (p<0.001), opioid agonist treatment (p=0.007), and benzodiazepines (p=0.001). There was no evidence for any trend in the other polysubstance use profiles, although single drug class use increased (51.9% to 64.7%, p=0.031). The different polysubstance use profiles were variously associated with psychosocial factors, including unstable housing and very high psychological distress, and other drug use risk behaviours, including non-fatal overdose, receptive and/or distributive needle sharing, and reusing one's own needles.

CONCLUSION

Same day polysubstance use has remained relatively common among this sample over time, although the typology has changed. Collectively, our findings point to diverse drug use patterns among people who inject drugs and reiterate the need for a range of harm reduction, treatment, and support options.

High-risk polysubstance use among LGBTQ+ people who use drugs in the United States: An application of syndemic theory

BACKGROUND

Compared to heterosexual and cisgender people, lesbian, gay, bisexual, transgender, queer, and other sexual and gender minority (LGBTQ+) people are more likely to develop problems with high-risk polysubstance use. According to syndemic theory, this disparity in high-risk polysubstance use is produced by the LGBTQ+ community's increased vulnerability to experiencing psychosocial (e.g., discrimination, unwanted sex) and structural (e.g., food insecurity, homelessness) conditions, greater likelihood of coping with concurrent health problems (e.g., human immunodeficiency virus [HIV]), and decreased opportunities to develop protective factors (e.g., social support, resilience).

METHODS

Data from 306 LGBTQ+ participants living in the United States (U.S.) with a lifetime history of alcohol and drug use were analyzed; 21.2% reported lifetime problems with 10 different drugs. Bootstrapped hierarchical multiple regression was used to test demographic correlates and syndemic predictors of high-risk polysubstance use. One-way ANOVA and post-hoc comparison tests were used to test subgroup differences by gender.

RESULTS

Results indicated that income, food insecurity, sexual orientation-based discrimination, and social support were associated with high-risk polysubstance use, explaining 43.9% of the variance of high-risk polysubstance use. Age, race, unwanted sex, gender identity-based discrimination, and resilience were not significant. Group comparison tests revealed that, compared to nonbinary people and cisgender sexual minority men and women, transgender individuals experienced significantly higher levels of high-risk polysubstance use and sexual orientation-based discrimination but significantly lower levels of homelessness and social support.

CONCLUSION

This study provided further evidence for conceptualizing polysubstance use as an adverse outcome of syndemic conditions. Harm reduction strategies, anti-discrimination laws, and gender-affirming residential treatment options should be considered in U.S. drug policy. Clinical implications include targeting syndemic conditions to reduce high-risk polysubstance use among LGBTQ+ people who use drugs.

Seeking order in patterns of polysubstance use

PURPOSE OF REVIEW

This review provides an overview of recent developments in understanding polysubstance use patterns across the lifespan, and advances made in the prevention and treatment of harm arising from polysubstance use.

RECENT FINDINGS

A comprehensive understanding of the patterns of polysubstance use is hampered by heterogeneity across study methods and types of drugs measured. Use of statistical techniques such as latent class analysis has aided in overcoming this limitation, identifying common patterns or classes of polysubstance use. These typically include, with decreasing prevalence, (1) Alcohol use only; (2) Alcohol and Tobacco; (3) Alcohol, Tobacco, and Cannabis; and finally (4) a low prevalence, Extended Range cluster that includes other illicit drugs, Novel Psychoactive Substances (NPS), and nonmedical prescription medications.

SUMMARY

Across studies, there are commonalities present in clusters of substances used. Future work that integrates novel measures of polysubstance use and leverages advances in drug monitoring, statistical analysis and neuroimaging will improve our understanding of how and why drugs are combined, and more rapidly identify emerging trends in multiple substance use. Polysubstance use is prevalent but there is a paucity of research exploring effective treatments and interventions.

Prevalence and correlates of methamphetamine use in transitional age youth experiencing homelessness or housing instability in San Francisco, CA

INTRODUCTION

Substance use, including methamphetamine use, is a contributing factor in HIV acquisition and treatment. Stimulant use is linked to mental health yet there is limited data from youth in community-based settings.

DESIGN

One hundred marginally housed or homeless transitional age youth (TAY) were recruited at Larkin Street Youth Services and completed a survey on mental health and substance use.

METHODS

We conducted secondary data analysis using multivariable logistic regression models to identify the correlates of methamphetamine use among TAY.

RESULTS

The participants' mean age was 22. Of those who reported methamphetamine use in the past 3 months, 64% were Gay, Bisexual, or Pansexual. Factors independently associated with methamphetamine use were; living with HIV (adjusted odds ratio [aOR] = 3.18, 95% CI = 1.11-9.15), depressive symptoms (aOR = 6.02, 95% CI = 1.46-24.78), symptoms of PTSD (aOR = 13.38, 95% CI = 1.59-112.73), polysubstance use in the past 3 months (aOR = 50.02, 95% CI = 9.72-257.46) and a history of injection drug use (aOR = 8.38, 95% CI = 1.87-37.53).

CONCLUSIONS

Results from this study suggest a need to develop, adapt, and rapidly implement comprehensive interventions that address the combined epidemics of substance use, HIV, and mental health among TAY.

CLINICAL RELEVANCE

This article examines factors associated with methamphetamine use among transitional age youth (TAY) experiencing homelessness or housing instability. Several factors were associated with use, including depression, PTSD, HIV status, polysubstance use, and injection drug use. These findings highlight the need for nurses to assess for methamphetamine use among youth as well as associated mental health and physical health problems. Nurses should link TAY who are using methamphetamine to evidence-based treatment programs to address substance use and comorbid conditions.

Predictors and motives of polydrug use in opioid users. A narrative review

PURPOSE OF REVIEW

To review the recent literature on predictors and personal motives of polydrug use in opioid users with a focus on combined use of opioids with stimulants, benzodiazepines and gabapentinoids.

RECENT FINDINGS

In North America, methamphetamine is now the most prevalent co-drug in opioid users and is responsible for high mortality rates. In Europe, opioids are rather combined with either cocaine, benzodiazepines or gabapentionoids, but recent data are lacking.Main personal motives of opioid users to combine opioids with methamphetamine or cocaine is to boost the opioid high, inhibit the withdrawal effects of heroin and have a cheaper alternative to maintain the opioid high. Risk factors of polydrug use by opioid users included being male, younger age, homelessness, high-risk sexual behavior, needle sharing, incarceration, poor mental health and recent use of cocaine or prescription opioids. The motives for co-use of opioids and gabapentinoids also include seeking a better high, lower price and to self-medicate pain/physical symptoms, including those resulting from withdrawal.

SUMMARY

When treating opioid users with polydrug drug use, special attention should be paid to dosing when in opioid agonist methadone/buprenorphine treatment and to the presence of physical pain. The validity of part of the personal motives seems questionable which deserves attention when counselling opioid users with polydrug use.

Polysubstance use in South Asia

PURPOSE OF REVIEW

Polysubstance use is very common in the world, but there has been limited research in this area. South Asia is sandwiched between two of the world's largest heroin producing areas: the Golden Crescent and the Golden Triangle. The burden and prevalence of polysubstance use have not been estimated in this region of the world. We review the research findings on polysubstance use in different South Asian countries. The review also comments on the gaps in knowledge regarding polysubstance use in this region of the world.

RECENT FINDINGS

The available literature on polysubstance use from South Asia suggests its widespread presence in the region, ranging from 20 to 90%, more commonly among illicit opioid drug users and injection drug users. Most of the available data is from epidemiological studies. There are few studies on the adverse effects of polysubstance use, but the limited data clearly suggests an elevated risk of comorbid psychopathology and health problems.

SUMMARY

Polysubstance use still lacks a consensus definition. There is a need of more research on its prevalence, effects on health, and prevention and treatment.

Can cannabis kill? Characteristics of deaths following cannabis use in England (1998-2020)

BACKGROUND

Cannabis is the most widely used illegal drug but is rarely considered a causal factor in death.

AIMS

This study aimed to understand trends in deaths in England where cannabinoids were detected at post-mortem, and to evaluate the clinical utility of post-mortem cannabinoid concentrations in coronial investigations.

METHODS

Deaths with cannabinoid detections reported to the National Programme on Substance Abuse Deaths (NPSAD) were extracted and analysed.

RESULTS

From 1998 to 2011, on average 7% of all cases reported to NPSAD had a cannabinoid detected (n = 110 deaths per year), rising to 18% in 2020 (n = 350). Death following cannabis use alone was rare (4% of cases, n = 136/3455). Traumatic injury was the prevalent underlying cause in these cases (62%, n = 84/136), with cannabis toxicity cited in a single case. Polydrug use was evident in most cases (96%, n = 3319/3455), with acute drug toxicity the prevalent underlying cause (74%, n = 2458/3319). Cardiac complications were the most cited physiological underlying cause of death (4%, n = 144/3455). The median average Δ9-tetrahydrocannabinol post-mortem blood concentrations were several magnitudes lower than previously reported median blood concentrations in living users (cannabis alone: 4.3 µg/L; cannabis in combination with other drugs: 3.5 µg/L).

CONCLUSIONS

Risk of death due to cannabis toxicity is negligible. However, cannabis can prove fatal in circumstances with risk of traumatic physical injury, or in individuals with cardiac pathophysiologies. These indirect harms need careful consideration and further study to better elucidate the role cannabis plays in drug-related mortality. Furthermore, the relevance of cannabinoid quantifications in determining cause of death in coronial investigations is limited.

Polydrug Definition and Assessment: The State of the Art

Polydrug use is a very common phenomenon and represents an important public health problem. The definition of the term has varied since its inception, and consequently so have forms of self-report evaluation. The aim of this review is to offer an overview of how the concept has evolved and its forms of evaluation through self-reporting. A search of the term polydrug was conducted on the PubMed portal up to August 2022, with a total of 2076 publications detected containing the word polydrug in their title, abstract or keywords. This includes publications that represent an advance in the definition and assessment of this construct through self-reports, which may be useful for researchers carrying out future studies in the field. The importance of distinguishing between concurrent and simultaneous polydrug use and the need to employ comparable measures in parameters for the frequency, magnitude and combination of psychoactive substances involved in polydrug use are two of the main recommendations emerging from this review.

Self-Control as Conceptual Framework to Understand and Support People Who Use Drugs During Sex

Few theory-informed interventions to support people who use drugs during sex have been conceptualized and developed. We conceptualize sexualized drug use, also referred to as chemsex or pharmacosex, as a self-control challenge, and draw on extant theory and research to propose intervention approaches that can be tailored to meet the differing needs of people who engage in sexualized drug use. We draw on a continuum perspective of sexualized drug use, in particular chemsex, and discuss the role of reasoned and automatic processes in behavioral decisions, as well as critical components of effective self-control of behavior. A self-control approach can empower people to tackle their sexualized drug use, and classify their experienced sex-related drug use as problematic. Self-control encompasses clarifying one's goals and identifying strategies to mitigate behaviors to achieve these goals, despite competing pharmacosex desires. Our approach to self-control sexualized drug use contains three critical components: goal setting, goal enactment, and goal progress appraisal and goal adjustment. Goals should be formulated specific, ambitious yet realistic, and tailored to the individual's needs and wishes. Goals may target aspects of drug use, protecting sexual health and mitigating negative impacts. Implementing goal enactment implies translating goals into concrete (short-term) actions to move toward the higher-order goal via goal intentions and action/coping plans. During the goal progress appraisal and adjustment stage, people compare their actual with their planned behavior. This reflection may result in goal adjustment through feedback loops to adjust their goals and action/coping plans. We propose that our self-control approach can guide the development of interventions to effectively support people to prevent or limit pharmacosex, and helps to effectively mitigate or reduce negative impacts via self-help, peer support or professional support, offered via personal counseling or digital tools.

Plasma Amino Acid Concentrations in Patients with Alcohol and/or Cocaine Use Disorders and Their Association with Psychiatric Comorbidity and Sex

(1) Background: Co-occurrence of mental and substance use disorders (SUD) is prevalent, but complicates their clinical courses, and specific biomarkers are required. Amino acids are altered in primary mental disorders; however, little is known about SUD and psychiatric comorbidity. Because most psychiatric disorders and biomarkers show sex differences, we investigated amino acids in men and women with alcohol and/or cocaine use disorders (AUD and/or CUD) and psychiatric comorbidity. (2) Methods: A cross-sectional study was conducted in 295 participants, who were divided into four groups (AUD, n = 60; CUD, n = 41; AUD + CUD, n = 64; and control, n = 130). Participants were clinically assessed, and plasma amino acid concentrations were analyzed in relation to sex, diagnosis of SUD and psychiatric comorbidity (3) Results: In the total sample, there were sex differences, and women showed lower Iso, Leu, Gln and Glu than men. While patients with CUD and AUD + CUD had higher Glu, Gly, Orn and Ser than controls, patients with AUD showed no differences. In SUD, patients with psychiatric comorbidity had lower Orn and higher Ala than non-comorbid patients in the AUD group. (4) Conclusions: There was a dysregulation of plasma amino acids in abstinent patients with SUD. However, our results suggest the importance of considering the clinical characteristics and sex in the validity of amino acids as potential biomarkers for SUD.