Substance Use Disorder

Substance Use Disorder (SUD) is a chronic, relapsing brain disorder defined by a pattern of substance use leading to clinically significant impairment or distress. DSM-5-TR unified the older diagnoses of 'substance abuse' and 'substance dependence' into a single SUD diagnosis with severity grading. It covers alcohol, cannabis, opioids, stimulants (cocaine, amphetamines), sedative-hypnotics (benzodiazepines, barbiturates), hallucinogens, inhalants, tobacco/nicotine, and other substances. References: DSM-5-TR, StatPearls (NCBI Bookshelf).

Substance Use Disorder (SUD) is a chronic, relapsing brain disorder defined by a pattern of substance use leading to clinically significant impairment or distress. DSM-5-TR unified the older diagnoses of 'substance abuse' and 'substance dependence' into a single SUD diagnosis with severity grading. It covers alcohol, cannabis, opioids, stimulants (cocaine, amphetamines), sedative-hypnotics (benzodiazepines, barbiturates), hallucinogens, inhalants, tobacco/nicotine, and other substances. SUD involves neurobiological changes in reward, motivation, memory, and executive control circuits. It is not a moral failing or a choice. The global burden is staggering: approximately 20 million adults in the USA have an SUD (SAMHSA, 2022), and the US opioid crisis produces roughly 100,000 overdose deaths per year. ICD-11 codes: 6C40-6C4Z (varies by substance). This information is for psychoeducation only.

DSM-5-TR defines SUD using 11 criteria, grouped into 4 clusters. Any 2 or more criteria within a 12-month period confirm diagnosis. Impaired control: (1) using more or longer than intended; (2) persistent desire or unsuccessful efforts to cut down; (3) spending excessive time obtaining, using, or recovering from the substance; (4) craving - strong urge or desire to use. Social impairment: (5) failure to fulfil major role obligations (work, school, home); (6) continued use despite persistent social/interpersonal problems caused by substance effects; (7) giving up or reducing important activities because of use. Risky use: (8) recurrent use in physically hazardous situations (driving, operating machinery); (9) continued use despite knowledge of a physical or psychological problem caused or worsened by the substance. Pharmacological indicators: (10) tolerance - needing increased amounts for the same effect, or diminished effect at the same dose; (11) withdrawal - characteristic withdrawal syndrome for the substance, or using the substance to relieve/avoid withdrawal. Severity: Mild (2-3 criteria), Moderate (4-5 criteria), Severe (6+ criteria). Specifiers include 'in early remission' (3-12 months without criteria except craving), 'in sustained remission' (12+ months), and 'on maintenance therapy.' Substance-specific signs: opioids - pinpoint pupils, respiratory depression, constipation, nodding; stimulants - dilated pupils, tachycardia, weight loss, agitation, psychosis at high doses; alcohol - hepatomegaly, spider angiomata, tremor, cognitive impairment; cannabis - conjunctival injection, increased appetite, impaired short-term memory; sedatives - slurred speech, ataxia, respiratory depression.

Genetic: heritability ranges from 40% (hallucinogens) to 70% (cocaine). Family history of SUD doubles or triples risk. Specific gene variants: ADH1B and ALDH2 (alcohol metabolism - the ALDH2*2 allele common in East Asian populations protects against alcohol use disorder by causing flushing, nausea); OPRM1 A118G (mu-opioid receptor variant affecting opioid reward sensitivity); CHRNA5 (nicotinic receptor subunit, increases nicotine dependence risk); CYP2A6 (nicotine metabolism - slow metabolisers smoke less). Psychological: childhood trauma and adverse childhood experiences (ACEs) - dose-response relationship where each additional ACE increases SUD risk. Pre-existing psychiatric disorders: ADHD (2-3x increased risk), bipolar disorder, PTSD, conduct disorder, borderline personality disorder. Sensation-seeking personality traits. Low distress tolerance. Environmental: peer substance use (strongest predictor in adolescence), early age of first use (before age 15 doubles lifetime SUD risk), substance availability, socioeconomic disadvantage, neighbourhood disorganisation, lack of parental monitoring, cultural norms around substance use. Developmental: adolescent brain vulnerability - the prefrontal cortex (impulse control, decision-making) does not fully mature until age ~25, while the limbic reward system matures earlier, creating a period of heightened vulnerability to reward-driven substance use.

SUD develops through a cycle of neuroadaptation involving three stages: binge/intoxication (reward), withdrawal/negative affect, and preoccupation/anticipation (craving). Each stage maps onto distinct brain circuits. Binge/intoxication stage: substances hijack the mesolimbic dopamine pathway. Dopamine neurons in the ventral tegmental area (VTA) project to the nucleus accumbens (NAc). All addictive substances increase dopamine release in the NAc, but through different mechanisms - opioids inhibit GABA interneurons in the VTA (disinhibiting dopamine neurons); stimulants block or reverse the dopamine transporter (DAT); alcohol enhances GABA and opioid peptide release; nicotine directly stimulates nicotinic acetylcholine receptors on VTA dopamine neurons. Withdrawal/negative affect stage: chronic substance use downregulates dopamine signalling (fewer D2 receptors, reduced dopamine release). The brain's anti-reward systems activate: dynorphin (kappa opioid receptor agonist) produces dysphoria; corticotropin-releasing factor (CRF) and norepinephrine drive stress and anxiety; the extended amygdala mediates negative emotional states. The result is anhedonia, irritability, and anxiety when not using - driving continued use to avoid withdrawal. Preoccupation/anticipation stage: prefrontal cortex dysfunction impairs decision-making, inhibitory control, and the ability to weigh long-term consequences against immediate reward. Drug-associated cues trigger dopamine release in the dorsal striatum via Pavlovian conditioning, producing intense craving. Glutamatergic projections from the prefrontal cortex to the NAc drive compulsive drug-seeking.

USA: approximately 46.3 million people aged 12+ had an SUD in the past year (SAMHSA 2022 NSDUH). Alcohol use disorder: ~29.5 million. Illicit drug use disorder: ~27.2 million (many individuals have both). Opioid use disorder: ~5.6 million. The opioid crisis: approximately 107,000 overdose deaths in 2023, with synthetic opioids (fentanyl) accounting for ~70% of deaths. Tobacco use disorder: ~28.3 million current cigarette smokers; tobacco kills approximately 480,000 Americans per year. Globally: ~271 million people used illicit drugs in 2017 (UNODC). Alcohol use disorder affects approximately 283 million people worldwide (WHO). Drug use directly caused 585,000 deaths in 2017 (60% increase from 2000). Alcohol caused 3 million deaths in 2016. Demographics: males are ~twice as likely as females to develop SUD (though the gap is narrowing for alcohol and cannabis). Peak onset: late teens to mid-20s. Higher prevalence among Native American/Alaska Native populations (USA), lower-income groups, individuals with disabilities (12-month prevalence 13.5%), and incarcerated populations. Comorbidity: approximately 50% of individuals with SUD have at least one co-occurring psychiatric disorder ('dual diagnosis'). Most common: depression, anxiety disorders, PTSD, ADHD, bipolar disorder, personality disorders (especially antisocial PD and borderline PD).

The mesolimbic dopamine pathway (VTA to nucleus accumbens) is the primary reward circuit hijacked by substances. Normal rewards (food, sex, social connection) produce modest, regulated dopamine surges. Addictive substances produce much larger, faster surges: cocaine increases NAc dopamine 3-5 fold; methamphetamine up to 12 fold; opioids 2-3 fold (via disinhibition). Neuroadaptation: with repeated exposure, the brain reduces dopamine signalling through receptor downregulation (fewer D2 receptors on postsynaptic neurons), reduced dopamine synthesis, and increased dopamine reuptake. This produces tolerance - more substance is needed for the same effect. The hedonic set point shifts: normal pleasures become less rewarding (anhedonia), and only the substance can restore baseline mood. Anti-reward systems: chronic substance use activates stress neurotransmitters in the extended amygdala - CRF, norepinephrine, and dynorphin - creating a persistent negative emotional state during abstinence. This drives continued use through negative reinforcement (using to relieve dysphoria rather than to get high). Prefrontal cortex impairment: executive function, impulse control, and judgement deteriorate with chronic use. Structural imaging shows grey matter volume reduction in dorsolateral PFC, orbitofrontal cortex, and anterior cingulate cortex. These deficits impair the ability to stop using despite awareness of consequences. Conditioned associations: drug-associated cues (people, places, paraphernalia, emotional states) acquire the ability to trigger dopamine release and craving through Pavlovian conditioning. These associations are encoded in the dorsal striatum and are remarkably persistent, contributing to relapse long after withdrawal resolves. Substance-specific pathophysiology: Opioids bind mu, kappa, and delta receptors; chronic use produces profound tolerance and physical dependence with severe withdrawal (diarrhoea, sweating, lacrimation, myalgia, insomnia). Alcohol inhibits NMDA glutamate receptors and enhances GABA-A receptor function; chronic use upregulates excitatory glutamate and downregulates inhibitory GABA, making abrupt cessation dangerous (seizures, delirium tremens).

Nicotine acts on nicotinic acetylcholine receptors in the VTA; chronic exposure desensitises receptors and produces physiological dependence with withdrawal (irritability, anxiety, difficulty concentrating).

History: screen all patients for substance use using validated tools - AUDIT-C or full AUDIT (alcohol), DAST-10 (drugs), CAGE-AID (general), single-item screening questions. The SBIRT model (Screening, Brief Intervention, Referral to Treatment) is recommended for primary care. Document: substances used, route, frequency, quantity, duration, age of first use, last use, withdrawal history, overdose history, prior treatment, injection drug use and related infections. Physical examination findings vary by substance: Alcohol - hepatomegaly, jaundice, spider angiomata, palmar erythema, gynecomastia, testicular atrophy, peripheral neuropathy, Dupuytren contracture, tremor, cerebellar signs (ataxia). Opioids - pinpoint pupils (miosis), track marks (IV use), skin abscesses, constipation, respiratory depression. Stimulants - dilated pupils (mydriasis), weight loss, dental decay ('meth mouth'), nasal septal perforation (snorted cocaine), skin excoriations (formication). Cannabis - conjunctival injection, dry mouth, cannabis hyperemesis syndrome (cyclical vomiting relieved by hot showers). Laboratory: urine drug screen (immunoassay with confirmatory GC-MS), blood alcohol level, liver function tests (GGT, AST, ALT; AST:ALT ratio >2:1 suggests alcoholic liver disease), MCV (elevated in chronic alcohol use), CDT (carbohydrate-deficient transferrin), hepatitis B/C serology, HIV testing, CBC, BMP, pregnancy test.

DSM-5-TR criteria: at least 2 of 11 criteria within a 12-month period. Severity: Mild (2-3), Moderate (4-5), Severe (6+). Each substance has its own specific SUD diagnosis (e.g. Alcohol Use Disorder, Opioid Use Disorder, Cannabis Use Disorder) using the same 11-criterion framework. Note: tolerance and withdrawal from prescribed medications taken as directed (e.g. opioids for chronic pain, benzodiazepines for anxiety) do not alone constitute SUD. SUD requires evidence of impaired control, social impairment, or risky use. ICD-11 uses a different framework: it distinguishes between 'Harmful Pattern of Substance Use' (6C4_) and 'Substance Dependence' (6C4_.1). ICD-11 dependence requires impaired control, physiological features (tolerance/withdrawal), and

persistent use despite harm - roughly analogous to DSM-5-TR moderate-severe SUD. Diagnosis should specify: current severity, remission status (early vs. sustained), maintenance therapy, and controlled environment.

Screening instruments: AUDIT (10 items, alcohol), AUDIT-C (3-item brief version), DAST-10 (drugs), CAGE-AID (4 items, general), TAPS (Tobacco, Alcohol, Prescription medication, and other Substance use tool), single-item screening question ('How many times in the past year have you used an illegal drug or used a prescription medication for non-medical reasons?' - positive if >=1). Severity and functional assessment: Addiction Severity Index (ASI), CIWA-Ar (Clinical Institute Withdrawal Assessment for Alcohol - Revised, scores 0-67), COWS (Clinical Opiate Withdrawal Scale, scores 0-48), Fagerstrom Test for Nicotine Dependence. Laboratory markers: urine drug screen (detection windows: cannabis 3-30 days; cocaine 2-4 days; opioids 2-3 days; amphetamines 1-3 days; alcohol 12-24 hours); ethyl glucuronide (EtG) in urine (detects alcohol up to 80 hours); phosphatidylethanol (PEth) in blood (detects chronic drinking over 3-4 weeks); CDT and GGT for chronic alcohol use. Risk assessment: evaluate for suicidal ideation (substantially elevated in SUD), overdose risk (especially during relapse after tolerance loss), injection-related infections (endocarditis, hepatitis, HIV), and withdrawal severity.

Primary psychiatric disorders: bipolar mania/hypomania (elevated mood, impulsivity, risk-taking) can mimic stimulant intoxication. Major depression with psychomotor retardation can mimic sedative effects. Psychotic disorders can mimic stimulant-induced psychosis. Distinguish by timeline: did psychiatric symptoms precede substance use (independent psychiatric disorder) or only occur during intoxication/withdrawal (substance-induced)? Medical conditions: thyroid disorders (anxiety, agitation in hyperthyroidism); hypoglycaemia (confusion, tremor, diaphoresis); delirium from medical causes (infections, metabolic derangements); seizure disorders; head injury. Substance-induced disorders: substance-induced psychosis, depressive disorder, anxiety disorder, or sleep disorder - these persist during intoxication or withdrawal and resolve after sustained abstinence. If symptoms persist beyond 1 month of sustained abstinence, a co-occurring independent psychiatric disorder is likely. Pain disorders: patients with chronic pain may develop tolerance and physical dependence on opioids without meeting full SUD criteria if they do not show impaired control or risky use. Behavioural addictions: gambling disorder (the only DSM-5-TR recognised behavioural addiction) shares neurobiological features with SUD.

Treatment of Substance Use Disorder (SUD) follows a chronic disease management model with phases of acute stabilisation, active treatment, and long-term recovery support.

Acute Management: Medically managed withdrawal (detoxification) is the first step for patients with physical dependence. Protocols are substance-specific. Alcohol withdrawal: benzodiazepines (chlordiazepoxide, lorazepam, or diazepam) titrated using CIWA-Ar protocol; thiamine 500 mg IV x 3 days then 100 mg PO daily to prevent Wernicke encephalopathy; folate 1 mg daily; monitor for seizures (peak 24-48 hours) and delirium tremens (peak 48-72 hours, mortality 5-15% if untreated). Opioid withdrawal: buprenorphine induction (start when COWS >=8-12), methadone taper, or clonidine-based symptomatic management. Benzodiazepine withdrawal: slow taper over weeks to months (10-25% dose reduction every 1-2 weeks). Stimulant withdrawal: supportive care; monitor for depression and suicidal ideation; no specific pharmacotherapy. Medication-Assisted Treatment (MAT): For opioid use disorder: buprenorphine/naloxone (Suboxone - partial mu agonist; can be prescribed in office settings); methadone (full mu agonist; dispensed daily through opioid treatment programmes; doses of 80-120 mg/day most effective); naltrexone extended-release injection (Vivitrol - mu antagonist, monthly injection; requires 7-10 days opioid-free before starting). All three reduce mortality by 50-70%, decrease illicit opioid use, reduce criminal activity, and improve social functioning. For alcohol use disorder: naltrexone (50 mg PO daily or 380 mg IM monthly - reduces heavy drinking days and craving; NNT ~12); acamprosate (666 mg TID - modulates glutamate/GABA, supports abstinence; most effective in maintaining abstinence once achieved); disulfiram (250 mg daily - inhibits aldehyde dehydrogenase, causing nausea, vomiting, flushing with alcohol ingestion; effectiveness depends on supervised administration). For tobacco use disorder: nicotine replacement therapy (patch 21/14/7 mg step-down; gum 2/4 mg; lozenge; inhaler; nasal spray); varenicline (Chantix - partial nicotinic receptor agonist, most effective single agent, OR 2.3 vs. placebo); bupropion SR (150 mg BID - norepinephrine/dopamine reuptake inhibitor). Combination NRT (patch + gum/lozenge) is more effective than single NRT. For stimulant use disorder: no FDA-approved pharmacotherapy; trials of topiramate, mirtazapine, and bupropion show modest or mixed results. Psychotherapy: Motivational Interviewing (MI) and Motivational Enhancement Therapy (MET) address ambivalence and strengthen motivation for change through empathy, developing discrepancy, rolling with resistance, and supporting self-efficacy. CBT teaches coping skills for high-risk situations, craving management, and relapse prevention. Contingency Management (CM) uses positive reinforcement (vouchers, prizes) for verified abstinence - strongest evidence for stimulant use disorders, with effect sizes exceeding all other psychotherapies. Twelve-Step Facilitation (TSF) promotes engagement with mutual-help programmes (AA, NA). Community Reinforcement Approach (CRA) restructures the patient's social environment to make abstinence more rewarding than substance use. Recovery Support: Mutual-help organisations (Alcoholics Anonymous, Narcotics Anonymous, SMART Recovery, Refuge Recovery) provide ongoing peer support. Peer support specialists with lived experience of recovery. Sober living environments provide structured, substance-free housing. Addressing social determinants (housing, employment, legal issues, family reunification, childcare) is essential for sustained recovery. Harm Reduction: For patients not ready for abstinence: naloxone distribution (all opioid users and their families should have naloxone kits); syringe services programmes (reduce HIV, hepatitis C transmission); supervised consumption sites (prevent overdose deaths); medication-assisted treatment without abstinence requirements; managed alcohol

programmes; drug checking services (fentanyl test strips).

SUD follows a chronic, relapsing course similar to diabetes or hypertension. Relapse rates of 40-60% are comparable to other chronic diseases and do not indicate treatment failure. Each treatment episode improves long-term outcomes even if relapse occurs. Longer treatment duration (at least 90 days for residential; 12+ months for MAT) predicts better outcomes. Opioid use disorder: untreated, 10-year mortality approaches 5-10%; MAT reduces mortality by 50-70%. Methadone and buprenorphine retention rates at 1 year are approximately 50-60%. Alcohol use disorder: approximately one-third achieve long-term abstinence, one-third improve significantly, and one-third have a chronic relapsing course. Cannabis use disorder: approximately 50% achieve sustained remission. Tobacco: quit rates are 7-30% at 1 year depending on intervention intensity. Positive prognostic factors: stable housing, employment, supportive social network, treatment engagement, MAT adherence, absence of co-occurring psychiatric disorders, later age of onset. Negative factors: polysubstance use, injection drug use, homelessness, antisocial personality disorder, untreated comorbid psychiatric illness.

Medical: Alcohol - cirrhosis, pancreatitis, cardiomyopathy, Wernicke-Korsakoff syndrome, alcohol-related dementia, increased cancer risk (oropharyngeal, oesophageal, hepatocellular, breast, colorectal), fetal alcohol spectrum disorder. Opioids - overdose death (respiratory depression), infectious endocarditis, hepatitis B/C, HIV, skin and soft tissue infections, osteomyelitis, constipation, hypogonadism. Stimulants - myocardial infarction, stroke, arrhythmias, psychosis, rhabdomyolysis, seizures, dental decay, nasal septal perforation. Cannabis - cannabinoid hyperemesis syndrome, impaired adolescent brain development, psychosis risk (especially high-potency THC in genetically predisposed individuals). IV drug use - endocarditis, septic emboli, hepatitis B/C, HIV, wound botulism. Tobacco - lung cancer, COPD, coronary artery disease, stroke, peripheral vascular disease, bladder cancer. Psychiatric: substance-induced psychosis, depression, anxiety; increased suicide risk (SUD increases lifetime suicide risk 5-10 fold); worsening of co-occurring psychiatric disorders. Social: incarceration, family disruption, child protective services involvement, homelessness, unemployment, poverty, driving under the influence and associated injuries/deaths, stigma and discrimination. Neonatal: neonatal abstinence syndrome (opioids), fetal alcohol spectrum disorder, low birth weight, premature birth.

Primary prevention: evidence-based school programmes (e.g. Life Skills Training, which has shown 50-75% reductions in tobacco, alcohol, and cannabis use); limiting adolescent access through age-restricted sales, taxation, advertising regulations; early identification and treatment of childhood ADHD, anxiety, and conduct disorder (which increase SUD risk); screening and brief intervention (SBIRT) in primary care and emergency departments.

Key patient education messages: SUD is a medical condition involving brain changes, not a character flaw. Treatment works - MAT for opioid use disorder is as evidence-based as insulin for diabetes. Relapse is common and does not mean treatment failed; it means the treatment plan needs adjustment. Naloxone saves lives - all opioid users and their household members should carry it. Recovery is possible at any age and after any number of relapses. Stigma kills - it prevents people from seeking treatment. Families should seek support (Al-Anon, Nar-Anon, CRAFT). Harm reduction messages: never use alone; carry naloxone; test drugs for fentanyl; use clean needles; avoid mixing depressants (opioids + benzodiazepines + alcohol is the leading cause of polysubstance overdose death).

Substance use has been part of human civilisation for millennia. Alcohol fermentation dates to ~7000 BCE. Opium has been cultivated since ~3400 BCE. Tobacco use by Indigenous Americans predates European contact. 1784: Benjamin Rush (signer of the Declaration of Independence) described chronic drunkenness as a disease. 1935: founding of Alcoholics Anonymous by Bill Wilson and Dr. Bob Smith. 1956: AMA declared alcoholism a disease. 1970: Controlled Substances Act established drug scheduling. 1971: Nixon declared the 'War on Drugs.' 1980: DSM-III distinguished 'Substance Abuse' from 'Substance Dependence.' 1994: DSM-IV refined the abuse/dependence distinction. 2000: Drug Addiction Treatment Act (DATA 2000) allowed office-based buprenorphine prescribing. 2013: DSM-5 unified abuse and dependence into Substance Use Disorder with severity grading, added craving as a criterion, and removed legal problems. 2016: Surgeon General's Report on Alcohol, Drugs, and Health declared addiction a public health crisis. 2023: opioid settlement funds ($50+ billion) began reaching communities.

SUD is one of the most stigmatised medical conditions. Language matters: 'substance use disorder' instead of 'addict' or 'junkie'; 'person with opioid use disorder' instead of 'opioid abuser'; 'medication-assisted treatment' instead of 'substitution.' The person-first language movement aims to reduce dehumanisation. Racial disparities in the US criminal justice response to drug use are well-documented. The crack cocaine epidemic of the 1980s-90s prompted harsh mandatory minimum sentences that disproportionately affected Black communities, while the opioid epidemic of the 2010s-20s (affecting predominantly White communities) prompted a more medicalised, harm-reduction-oriented response. The 2020 Oregon Drug Decriminalization Measure (110) represented a policy shift, though it was partially repealed in

from ALDH2*2 in some East Asian populations); khat in East Africa and the Arabian Peninsula; betel nut in South/Southeast Asia; coca leaf chewing in Andean cultures (distinct from refined cocaine). Religious prohibitions (Islam, Mormonism, some Protestant denominations) reduce alcohol-related harm in adherent populations. Treatment access is profoundly unequal. Only about 10% of people with SUD receive any treatment. Barriers include: lack of insurance or affordability, geographic distance to treatment facilities (especially in rural areas), stigma, waiting lists, lack of MAT-prescribing providers, criminal justice system as de facto treatment system.

Active research areas: development of vaccines against opioids, nicotine, methamphetamine, and cocaine (targeting drug molecules in the bloodstream before they reach the brain). Long-acting injectable formulations: monthly or quarterly buprenorphine implants/injections, extended-release naltrexone. Novel medications: orexin receptor antagonists (reduce drug-seeking behaviour in preclinical models); GLP-1 receptor agonists (semaglutide, liraglutide) show unexpected reductions in alcohol and substance use in observational studies. For stimulant use disorder: lisdexamfetamine, injectable naltrexone + bupropion combination, and anti-methamphetamine monoclonal antibodies are in clinical trials. Psychedelic-assisted therapy: psilocybin for alcohol use disorder (phase II trials show large effect sizes); MDMA-assisted therapy for PTSD with co-occurring SUD; ibogaine for opioid use disorder (unregulated, safety concerns). Digital therapeutics: reSET and reSET-O (FDA-cleared apps delivering contingency management and CBT for SUD). Pharmacogenomics: CYP2D6 genotyping for methadone dosing; OPRM1 genotyping for naltrexone response prediction. Neuroimaging biomarkers: fMRI cue-reactivity as relapse predictor. Harm reduction research: overdose prevention centres, drug checking, managed alcohol programmes.

APA. (2022). Diagnostic and Statistical Manual of Mental Disorders (5th ed., text rev.; DSM-5-TR). APA Publishing. Sadock BJ, Sadock VA, Ruiz P. (Eds.). (2024). Kaplan & Sadock's Comprehensive Textbook of Psychiatry (11th ed.). Wolters Kluwer. StatPearls [Internet]. Substance Use Disorder. NCBI Bookshelf. StatPearls Publishing. SAMHSA. (2022). National Survey on Drug Use and Health (NSDUH). WHO. (2022). ICD-11 for Mortality and Morbidity Statistics. Geneva: World Health Organization.

NIMH: https://www.nimh.nih.gov SAMHSA National Helpline: https://www.samhsa.gov/find-help/national-helpline (1-800-662-4357) NIDA (National Institute on Drug Abuse): https://nida.nih.gov StatPearls - Substance Use Disorders: https://www.ncbi.nlm.nih.gov/books/NBK570642/ WHO ICD-11: https://icd.who.int Alcoholics Anonymous: https://www.aa.org Narcotics Anonymous: https://www.na.org SMART Recovery: https://www.smartrecovery.org Crisis: 988 (US Suicide & Crisis Lifeline); Text HOME to 741741 (Crisis Text Line)