Questions: Substance Use Disorder: Diagnosis and Types

Question 1

A patient has been taking prescription opioids for chronic pain for two years. They have developed tolerance (needing higher doses for the same effect) and experience withdrawal symptoms when doses are missed. They take their medication as prescribed, have no cravings, and their work and relationships are unaffected. Do they have Substance Use Disorder?

• A. Yes — tolerance and withdrawal are the two pharmacological criteria for SUD
• B. No — tolerance and withdrawal are only 2 of 11 DSM-5 criteria; SUD requires impaired control, social problems, or risky use that this patient does not exhibit
• C. Yes — any physical dependence on a controlled substance meets the DSM-5 definition of SUD
• D. No — SUD cannot be diagnosed in patients receiving legally prescribed medications

Answer: (B)

Physical dependence (tolerance and withdrawal) can result from appropriate medical treatment without any of the impaired control, social impairment, or risky use criteria. SUD requires meeting 2+ of 11 criteria with clinically significant impairment — and the pharmacological criteria are just 2 of those 11. The core of SUD is loss of control and continued use despite harm, which this patient does not exhibit. Conversely, a patient could have SUD without any tolerance or withdrawal (e.g., binge drinking that meets control and harm criteria but not yet pharmacological ones).

Question 2

A person with severe alcohol use disorder has lost their job and family due to drinking, has repeatedly tried and failed to quit, and desperately wants to stop. Neurobiologically, why is stopping so difficult despite strong motivation?

• A. The person lacks sufficient willpower and has not made a genuine commitment to stop
• B. Withdrawal symptoms alone create intolerable physical pain that prevents cessation without medical support
• C. Chronic alcohol use downregulates baseline dopamine, reduces D2 receptors, and weakens prefrontal inhibitory control — the person now uses to feel normal, not euphoric, because their reward system can no longer generate baseline pleasure without the substance
• D. The mesolimbic pathway is permanently destroyed and cannot recover under any circumstances

Answer: (C)

Chronic substance use produces homeostatic downregulation: baseline dopamine release decreases, D2 receptor density falls, and prefrontal cortex activity is reduced. The person is no longer pursuing euphoria — their depleted reward system can no longer generate it. They use to relieve the anhedonia and dysphoria of a chronically understimulated system — to feel normal. This is why willpower-based approaches alone are insufficient and why treatment combines pharmacological stabilization with psychosocial intervention to rebuild adaptive reward-seeking.

Question 3

In DSM-5, a person meeting 6 or more of the 11 SUD criteria has severe SUD, while someone meeting 2 has mild SUD — reflecting a dimensional rather than categorical model of addiction severity.

• T. True
• F. False

Answer: True

The DSM-5 replaced the DSM-IV's separate 'abuse' and 'dependence' categories with a single dimensional SUD construct. Severity is determined by criterion count: mild (2–3 criteria), moderate (4–5), severe (6+). This dimensional approach reflects clinical reality — the person who occasionally drinks more than intended is meaningfully different from someone whose drinking has cost them their job, family, and health — and better predicts treatment intensity needed and prognosis.

Question 4

The presence of tolerance and withdrawal symptoms is sufficient to diagnose Substance Use Disorder.

• T. True
• F. False

Answer: False

Tolerance and withdrawal are the pharmacological criteria — 2 of the 11 DSM-5 criteria. Physical dependence can develop in patients receiving appropriate medical treatment (e.g., opioids for chronic pain, benzodiazepines for seizures) without impaired control, social impairment, or risky use. Meeting only these 2 criteria does not constitute SUD. Conversely, behavioral addictions (gambling, gaming) can produce clear SUD patterns — impaired control, social harm, continued use despite consequences — with minimal or no physical dependence.

Question 5

Why does the DSM-5 framework treat tolerance and withdrawal as only two of eleven criteria for SUD, rather than treating physical dependence as the defining feature of addiction?

Model answer: Because physical dependence can occur without problematic use — as in medically supervised opioid therapy — and problematic use can occur without physical dependence, as in gambling or stimulant abuse. The defining feature of SUD is loss of control over use and continued use despite harm, which the pharmacological criteria alone do not capture.

A cancer patient on long-term morphine may be physically dependent (tolerant and subject to withdrawal if stopped abruptly) while taking medication exactly as prescribed with no impaired control, no cravings, no neglected obligations, and no risky use. None of the control or harm criteria apply. Conversely, a person with a gambling disorder meets multiple impaired-control and social-impairment criteria with no pharmacological dependence. The 11-criterion dimensional framework captures the behavioral and functional reality of loss-of-control and harm-despite-consequences, which is the actual clinical problem.