Drug Abuse

Drug Abuse — formally classified in DSM-5-TR as Substance Use Disorders (other than alcohol and tobacco) — includes problematic use of cannabis, opioids, stimulants, sedatives, hallucinogens, inhalants, and other psychoactive substances, with severity ranging from mild to severe.

Overview

“Drug abuse” is a lay and historical term for problematic use of psychoactive substances other than alcohol and tobacco. The DSM-5-TR formally classifies these conditions as Substance Use Disorders (SUDs), with separate diagnoses for cannabis (304.30), hallucinogens (304.50), inhalants (304.60), opioids (304.00), sedative-hypnotic-anxiolytics (304.10), stimulants (304.40), and other or unknown substances (304.90). The DSM-5 (2013) consolidated the previous DSM-IV “Abuse” and “Dependence” diagnoses into a single Substance Use Disorder diagnosis with severity specifiers (mild: 2-3 criteria, moderate: 4-5, severe: 6+).

Past-year prevalence of any non-alcohol, non-tobacco SUD in Canadian adults is approximately 4-5%; lifetime prevalence approximately 12%. Cannabis use disorder is the most common (past-year ~3%), followed by stimulant, opioid, sedative, and hallucinogen use disorders. The opioid epidemic has produced substantial increases in opioid-related morbidity and mortality across North America since the early 2000s, with fentanyl contamination of the illicit drug supply driving record overdose deaths in recent years.

The clinical pattern across substances shares core features: impaired control, social impairment, risky use, and pharmacological features (tolerance, withdrawal). Substances differ substantially in withdrawal severity, medical complications, treatment options, and recovery trajectories. Specific medication-assisted treatments are well-established for opioid use disorder (methadone, buprenorphine, naltrexone) but limited for stimulant, cannabis, and hallucinogen use disorders.

Comorbidity with mental-health conditions is the rule. Trauma history, mood disorders, anxiety disorders, ADHD, and personality disorders all elevate SUD risk and complicate treatment. Integrated dual-diagnosis treatment produces better outcomes than sequential or parallel care.

Treatment is highly effective for most who engage. Combinations of pharmacotherapy (where available), psychotherapy, peer support, and harm-reduction services produce meaningful improvement. Recovery is typical with sustained treatment, though relapse is common and frequently part of the recovery process. Modern approaches increasingly integrate harm-reduction (naloxone distribution, supervised consumption, drug-checking) with abstinence-oriented options.

Signs and symptoms

Loss of control over use — Use in larger amounts or over a longer period than intended; repeated unsuccessful efforts to cut down or stop.
Significant time on substance-related activities — Substantial time obtaining, using, or recovering from the substance.
Craving — Persistent strong desire or urge to use the substance.
Role obligation failure — Recurrent use resulting in failure to fulfill major obligations at work, school, or home.
Continued use despite social problems — Continued use despite persistent social or interpersonal problems caused or exacerbated by use.
Activities given up or reduced — Important social, occupational, or recreational activities given up or reduced.
Use in hazardous situations — Recurrent use in physically hazardous situations (driving, swimming, operating machinery).
Continued use despite physical or psychological harm — Continued use despite knowledge of having a persistent or recurrent physical or psychological problem caused or exacerbated by the substance.
Tolerance — Need for markedly increased amounts to achieve effect, or markedly diminished effect with same amount.
Withdrawal — Substance-specific withdrawal syndrome on cessation, or use of substance to relieve or avoid withdrawal. Severity ranges from mild discomfort to medical emergency depending on substance.

Diagnostic context

The DSM-5-TR Substance Use Disorder criteria are largely consistent across substances, with specific clinical features by substance class. Severity is determined by number of criteria met:

Mild SUD: 2-3 criteria.
Moderate SUD: 4-5 criteria.
Severe SUD: 6 or more criteria.

Substance-specific clinical considerations:

Cannabis Use Disorder: increasing cannabis potency (THC concentration) is associated with elevated risk of dependence, psychotic disorders, and cognitive effects, particularly in adolescents.
Opioid Use Disorder: highest mortality risk of any SUD due to overdose; fentanyl contamination of illicit supply has substantially elevated overdose mortality. MAT (methadone, buprenorphine) is the standard of care.
Stimulant Use Disorder: includes cocaine, methamphetamine, prescription stimulants. No FDA-approved medication; behavioral treatments (contingency management) have strongest evidence.
Sedative-Hypnotic Use Disorder: benzodiazepines, z-drugs, barbiturates. Withdrawal can be life-threatening; medical detoxification is required. Iatrogenic dependence from prescribed long-term use is common.
Hallucinogen Use Disorder: classic hallucinogens (psilocybin, LSD), MDMA. Generally lower addictive potential than other classes; emerging therapeutic applications (psilocybin for depression, MDMA for PTSD) are reshaping clinical understanding.
Inhalant Use Disorder: volatile substances. Particularly common in adolescents; produces rapid intoxication and substantial neurotoxicity with sustained use.

Differential diagnosis includes mood, anxiety, and psychotic disorders with secondary substance use; substance-induced mood/anxiety/psychotic disorders; medical conditions (delirium, dementia, endocrine disorders); medication side effects; and primary psychiatric conditions presenting with substance use as a coping strategy.

Causes and risk factors

SUD development involves interaction of biological, psychological, and social factors:

Genetic factors: heritability ~40-60% across substances. Substantial genetic overlap across substance classes (“general addiction vulnerability”) and with comorbid conditions (depression, ADHD, schizophrenia).

Neurobiological factors: repeated substance exposure produces neuroplastic changes in mesolimbic dopamine, prefrontal executive control, amygdala stress, and habenula aversion circuits. Substance-specific mechanisms (opioid receptors for opioids, GABA for sedatives, dopamine reuptake for stimulants) modify this general pattern.

Developmental factors: early initiation (before age 15), childhood adversity, family history, ADHD, conduct problems, and early peer use all elevate risk.

Psychological factors: trauma history, mood disorders, anxiety disorders, PTSD, ADHD, and personality disorders elevate risk and complicate treatment. Self-medication of underlying mental-health symptoms is common.

Social and environmental factors: peer use, family use, accessibility, neighborhood disorder, poverty, discrimination, housing instability, and trauma exposure all contribute.

Substance-specific risk factors: route of administration (intravenous and inhaled produce faster onset and higher addictive potential), pharmacokinetic profile (rapid-onset, short-acting substances are more addictive), substance accessibility, social context, and contamination of supply (fentanyl in opioids has dramatically elevated mortality).

Comorbidity: approximately 50-60% of individuals with SUDs have a co-occurring mental-health condition. Co-occurring tobacco use disorder is extremely common across SUD populations.

Typical treatments

Treatment is matched to substance, severity, and patient characteristics. Evidence-based approaches:

Pharmacotherapy / Medication-Assisted Treatment:

Opioid Use Disorder: methadone, buprenorphine (with or without naloxone), extended-release naltrexone. MAT substantially reduces mortality; international standard of care.
Tobacco Use Disorder: nicotine replacement, varenicline, bupropion.
Cannabis Use Disorder: no FDA-approved medication; some evidence for N-acetylcysteine and gabapentin.
Stimulant Use Disorder: no FDA-approved medication; contingency management and CBT are first-line.
Sedative-Hypnotic Use Disorder: medically supervised gradual taper; no agonist-substitution approach analogous to opioid MAT.

Psychotherapy:

Cognitive Behavioral Therapy — strong evidence across substances.
Motivational Interviewing — useful for engagement.
Contingency Management — particularly strong for stimulants; underused in clinical practice.
Couples and family therapy.
Trauma-focused therapies for co-occurring PTSD.
Mindfulness-Based Relapse Prevention.

Peer support: Narcotics Anonymous, Cocaine Anonymous, SMART Recovery, Refuge Recovery, LifeRing.

Levels of care: outpatient, intensive outpatient, partial hospitalization, residential, medical detoxification (required for sedative-hypnotic withdrawal due to seizure risk).

Harm reduction: naloxone distribution, supervised consumption sites, syringe services, drug-checking (testing for fentanyl contamination), low-barrier MAT access. Reduces mortality and disease transmission for individuals not yet engaging in abstinence-oriented treatment.

Integrated dual-diagnosis treatment for co-occurring mental-health conditions.

Treatment of comorbid SUDs: co-occurring tobacco use is extremely common and warrants explicit attention; concurrent treatment improves overall outcomes.

When to seek help

Professional support is indicated when:

You have been unable to control substance use despite repeated efforts.
Use is producing significant consequences in relationships, work, finances, health, or legal status.
You experience cravings, tolerance, or withdrawal symptoms.
You are using opioids from an illicit source (high overdose risk due to fentanyl contamination).
You are using sedatives daily and have tried to stop without success.
Co-occurring mental-health conditions (depression, anxiety, PTSD, ADHD) are present.
You are concealing use from family, partners, or healthcare providers.

If you are experiencing or witnessing an opioid overdose, contact emergency services (911) immediately and administer naloxone if available. Naloxone kits are available free at most Canadian pharmacies without prescription. If you are physically dependent on sedative-hypnotics or alcohol, do not stop abruptly without medical supervision — withdrawal can be life-threatening.

Free 24-hour crisis and addictions support: 1-866-332-2322 (Alberta Health Services Addiction Helpline, 24/7), 1-866-531-2600 (ConnexOntario, 24/7), 1-866-585-0445 (Drug & Alcohol Helpline of Ontario), 9-8-8 (Suicide Crisis Helpline), 1-833-456-4566 (Talk Suicide Canada).

Frequently asked questions

Is "drug abuse" still the right term?

Clinically, the formal terminology is "Substance Use Disorder" with severity specifiers. "Drug abuse" remains common in lay and historical clinical usage but is being replaced by less stigmatizing terminology in contemporary practice. The clinical concept is the same.

Are some drugs more addictive than others?

Yes. Opioids (especially fentanyl, heroin), methamphetamine, cocaine, and nicotine are among the most addictive substances. Cannabis, hallucinogens, and inhalants generally have lower addictive potential, though all can produce SUD in vulnerable individuals.

Will medication-assisted treatment work for stimulant use?

No FDA-approved medication for stimulant use disorder exists. Contingency management has the strongest evidence base. Various medications are being studied (modafinil, bupropion, mirtazapine, others) with mixed results.

Should I worry about fentanyl in the drug supply?

Yes, particularly for opioids and increasingly for other substances (cocaine, methamphetamine, MDMA). Fentanyl contamination has driven record overdose deaths across North America. Use of drug-checking services, fentanyl test strips, never using alone, and having naloxone available substantially reduce overdose risk.

Can I withdraw safely at home?

Depends on the substance. Opioid withdrawal is uncomfortable but rarely medically dangerous; cannabis and stimulant withdrawal are typically not medically dangerous. Alcohol and sedative-hypnotic withdrawal can be life-threatening (seizures, delirium) and require medical supervision.

How long does treatment take?

Acute stabilization typically requires weeks to months. Sustained recovery is typically multi-year. MAT for opioid use disorder is often appropriate long-term. Many people experience one or more relapses on the path to sustained recovery; relapse responds to renewed treatment.

References

American Psychiatric Association. (2022). Diagnostic and Statistical Manual of Mental Disorders (5th ed., text rev.). APA.
National Institute on Drug Abuse. (2018). Principles of Drug Addiction Treatment: A Research-Based Guide (3rd ed.).
World Health Organization. (2022). International Classification of Diseases, Eleventh Revision (ICD-11). Disorders Due to Substance Use.
Volkow, N. D., et al. (2019). Use and misuse of opioids in chronic pain. Annual Review of Medicine, 69, 451–465.
Bruneau, J., et al. (2018). Management of opioid use disorders: A national clinical practice guideline. Canadian Medical Association Journal, 190(9), E247–E257.

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The ShiftGrit Clinical Editorial Team combines the insight of registered psychologists, provisional psychologists, and trained writers to create accessible, evidence-informed therapy resources. All content is clinically reviewed by a Registered Psychologist.