Substance Use Screening and Withdrawal Instruments

In primary care and hospital settings, screening instruments sit at the front of a brief intervention pathway: a positive score leads to a conversation, a fuller assessment or a referral. The AUDIT-C is short enough to be used routinely, and in some health systems it is the standard annual alcohol screen. The withdrawal scales are used at the bedside and repeated at intervals, because withdrawal changes over hours and treatment is increasingly given in response to the score rather than on a fixed schedule.

In research, these instruments do two jobs. They characterise participants at baseline, since alcohol and tobacco use modify outcomes in almost every condition, and they serve as outcomes in trials of treatments for substance use itself. The Fagerström score predicts how hard quitting will be, and withdrawal scale totals are used to compare detoxification regimens. Self-report of substance use is sensitive, so how the questions are asked, and who sees the answers, affects what people disclose.

Check that the instrument matches the task. A screening questionnaire cannot grade withdrawal, and a withdrawal scale says nothing about whether someone has a use disorder. Using the CIWA-Ar to decide whether a patient drinks heavily, or the AUDIT to decide when to give medication, is a category error.

Check the definitions that sit underneath the questions. The size of a standard drink differs between countries, from about 8 grams of alcohol in a United Kingdom unit to about 14 grams in the United States, so the same AUDIT answer means different amounts in different places. The Fagerström test was built for cigarettes and does not transfer to e-cigarettes or heated tobacco. And the withdrawal scales assume a patient who can communicate, and their items overlap with other conditions such as sepsis, anxiety and withdrawal from other drugs.

Check how disclosure will be protected. People under-report substance use when they fear consequences, and digital self-completion often produces more honest answers than a face to face interview. Finally, check that a positive screen leads somewhere. Screening without a defined next step, whether a brief intervention, an assessment or a referral, identifies a problem and then leaves it where it was.

What is the difference between the AUDIT and the AUDIT-C?

The AUDIT-C is the first three questions of the ten item AUDIT, covering consumption only. It is quicker and performs nearly as well for detecting hazardous drinking. The full AUDIT adds questions about dependence and harm, which help distinguish risky drinking from an established alcohol use disorder.

Can a screening questionnaire diagnose an alcohol use disorder?

No. A positive screen identifies people who need further assessment. Diagnosis requires a clinical assessment against diagnostic criteria, which cover control, harm and dependence as well as the amount consumed.

When is the CIWA-Ar not reliable?

When the patient cannot communicate, for example if they are intubated, delirious or do not share the assessor's language, and when another condition such as sepsis or hepatic encephalopathy produces similar signs. In those situations the score cannot be taken at face value.

Why has fentanyl changed how the COWS is used?

Fentanyl accumulates in body fat, so buprenorphine can precipitate withdrawal even when the COWS score has reached the usual starting threshold. Many services now use low dose induction methods that do not rely on waiting for a particular score.