Substance Use Disorders in ICD-10: The Complete F10–F19 Code Guide

The highest-volume family in Indian clinical practice. Watch the .3/.4 boundary: uncomplicated withdrawal (F10.3) can escalate to withdrawal delirium (F10.4 — delirium tremens), which carries real mortality and warrants ICU-capable care; clinically, that is why heavy drinkers should never stop abruptly without supervision (patient-facing explainer: alcohol withdrawal symptoms). F10.6 (amnesic syndrome) and F10.7 (residual disorders) capture the chronic neuropsychiatric burden.

Dependence (F11.2) develops rapidly; withdrawal (F11.3) is intensely distressing but rarely life-threatening in otherwise healthy adults — the danger concentrates in overdose (respiratory depression) and post-detox loss of tolerance. Pharmacological treatment (e.g., buprenorphine — a high-affinity partial mu-agonist) is standard of care alongside psychosocial treatment.

Frequently miscoded as harmless. Harmful use (F12.1) and dependence (F12.2) are common in students and young adults, and cannabis-induced psychotic disorder (F12.5) — with relapsing course in vulnerable users — is a recurring inpatient presentation. Patient-facing resources: cannabis addiction and bhang addiction.

The benzodiazepine family. Often iatrogenic — dependence (F13.2) growing quietly out of a legitimate prescription. Like alcohol (both are GABAergic), sedative withdrawal (F13.3/.4) can produce seizures and delirium: tapering and supervision are mandatory, not optional.

Coded separately from other stimulants. Abuse/harmful use (F14.1) presents with cardiovascular events, paranoia and financial collapse; withdrawal (F14.3) is dominated by crash dysphoria, hypersomnia and craving rather than dramatic physical signs.

Amphetamine-type stimulants and MDMA sit here — clinically important in India's party-drug belt — along with caffeine. Stimulant-induced psychotic disorder (F15.5) can mimic paranoid schizophrenia; the substance history is the differentiator.

LSD and psilocybin-type agents. Dependence is uncommon; the clinically significant codes are intoxication (F16.0), psychotic disorder (F16.5) and residual/flashback phenomena (F16.7).

The most prevalent dependence (F17.2) and the most undercoded — documenting it changes cessation-support delivery and risk profiles across every specialty. India-specific: smokeless tobacco (gutkha, khaini) codes here too.

Inhalant use — glue, thinner, petrol — concentrated in adolescents and street-involved children. Brief intoxication (F18.0), significant organ toxicity, and dependence (F18.2) in chronic users. A high-vigilance code in paediatric and community settings.

Two uses: genuine polysubstance dependence where no single substance predominates (code F19.2 only when the picture is truly mixed — prefer the specific family when one drug dominates), and substances unclassifiable elsewhere. In practice, polysubstance presentations are among the most complex to treat and frequently co-occur with psychiatric illness — the population our dual diagnosis pathway exists for.

Companion lecture: how substances hijack the mesolimbic dopamine pathway, the binge–withdrawal–craving cycle, and where naltrexone, acamprosate, disulfiram and buprenorphine act — the neurobiology underneath every code on this page.

Four habits that keep records clean and clinically useful:

1. Code the state, not just the substance. "F10" alone is incomplete; "F10.2" tells the next clinician the patient is dependent, which changes withdrawal precautions on any admission — surgical wards included.
2. Dependence supersedes harmful use. Once .2 criteria are met, stop coding .1 — a common audit finding.
3. Code every substance meeting criteria. Alcohol dependence with tobacco dependence is F10.2 + F17.2, and the second code is the one that gets the cessation referral written.
4. Document the evidence behind the fourth character. "F10.3" without recorded tremor, sweating, or pulse trend will not defend itself in an audit — or an insurance query.