Opioid Use Disorder

DSM-5 OUD: ≥2 criteria within 12 months: tolerance, withdrawal, larger use than intended, persistent desire to cut down, time spent obtaining, social/occupational impact, continued use despite harm, hazardous use, craving, role failure, interpersonal problems, withdrawal of activities. Severity by criteria count: mild 2–3, moderate 4–5, severe ≥6. Baseline: • Bloods: FBC, U&E, LFTs, BBV (HIV, HBV, HCV), syphilis. • Urine drug screen. • Pregnancy test in women. • ECG (QTc — methadone risk). • Mental health screening. • Social: housing, family, employment, criminal justice. • Domestic abuse + safeguarding (children at home).