A 32-year-old man with a 5-year history of heroin use presents to the de-addiction centre reporting daily use and inability to cut down. He denies any recent overdose but admits to tolerance and withdrawal symptoms on missing doses. Which investigation is most appropriate to confirm the diagnosis of opioid use disorder and assess the severity of dependence?

Explanation

## Diagnostic Assessment of Opioid Use Disorder ### Role of Severity of Dependence Scale (SDS) **Key Point:** The Severity of Dependence Scale is a validated, brief 5-item self-report instrument that quantifies the severity of opioid dependence and predicts treatment outcome. It directly measures psychological and physical dependence symptoms. ### Why SDS is the Investigation of Choice The SDS questionnaire assesses: - Difficulty controlling use - Worry about use - Difficulty thinking of anything else - Physical withdrawal symptoms - Difficulty reducing use Scores range from 0–15, with higher scores indicating greater dependence severity. This guides treatment intensity and prognosis. ### Complementary vs. Diagnostic Investigations | Investigation | Purpose | Role in OUD Diagnosis | |---|---|---| | **Urine drug screening** | Detects presence of opioids | Confirms recent use, NOT severity | | **SDS questionnaire** | Quantifies dependence severity | **Gold standard for assessing dependence** | | **LFTs & hepatitis serology** | Screens for complications | Assesses comorbidity, NOT diagnosis | | **EEG** | Neurophysiological recording | No role in OUD assessment | **High-Yield:** While urine drug screening confirms opioid use, it does NOT measure dependence severity or psychological dependence. The SDS directly addresses the diagnostic criteria (tolerance, withdrawal, loss of control) outlined in DSM-5. **Clinical Pearl:** SDS is particularly useful in resource-limited settings (common in India) as it requires no laboratory equipment, is brief (< 5 minutes), and has been validated in Indian populations. [cite:ICD-10 F11.2, DSM-5 Opioid Use Disorder criteria]