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Substance use problems: Screening

Patients rarely present seeking help for substance use disorders. They are more likely to present with a medical, psychological or social condition caused by their substance use. This means that substance use should be part of the differential diagnosis for various medical and psychiatric disorders.

Substance use does not equal addiction or a substance-related disorder. It is necessary to differentiate these conditions because prognosis and management differ.

Key screening questions for substance use problems

Is the patient intoxicated (mild to severe) or in withdrawal?

Intoxication is the immediate influence of a substance. It is specific to a particular substance or class of substance.

Withdrawal is a distinct syndrome characteristic of the discontinuation of a substance.

As a general rule, intoxication with stimulants (e.g., cocaine, methamphetamine) leads to increased arousal, whereas withdrawal is associated with somnolence. The opposite is true with depressant drugs (e.g., opioids, benzodiazepines).

Is substance use involved?

When a patient presents with any psychiatric condition, screening for substance use is necessary. In addition, the following physical conditions are red flags for possible substance use:

General signs and symptoms:

  • fatigue
  • weight loss
  • hypertension
  • frequent trauma
  • odour of alcohol on breath

GI problems:

  • hepatitis
  • gastritis
  • pancreatitis

Renal problems:

  • frequency
  • hematuria
  • shrunken bladder

Neurological problems:

  • seizures
  • tremors

Respiratory problems:

  • chronic cough


  • HIV
  • hepatitis C
  • hepatitis B
  • sexually transmitted infections
  • infective endocarditis
  • signs of injection drug use (e.g., "track marks")

Obstetric problems:

  • intrauterine growth restriction
  • recurrent pregnancy loss

Social and family problems:

  • divorce
  • child protection agency involvement
  • spousal abuse

Occupational, legal and economic problems:

  • job loss
  • impaired driving
  • arrest
  • sudden loss of money
  • poor school performance

Screening for substance use problems in all patients

Ask all patients over nine years of age about their use of alcohol, tobacco, prescription drugs (e.g., benzodiazepines, opioids), over-the-counter drugs (e.g., dimenhydrinate, acetaminophen with codeine) and street drugs (e.g., cocaine, cannabis, and heroin).

Screening questionnaires (e,g,, the CAGE) can help to quickly identify a substance use problem or determine the level of dependence. Once a substance use disorder is identified or suspected, ask about:

  • the degree of use
  • the consequences of use
  • the patient's readiness to engage in treatment

Implementing effective screening strategies

Patients often have difficultly disclosing and quantifying their substance use. Inquiring about how much they use rather than if they use gives them permission to be more honest.

Here are some other strategies to overcome the shame, fear or reluctance to disclose that patients may feel:

Preparing the patient for the question: "To better understand your condition I am going to ask you questions about your use of alcohol, tobacco and other drugs. Is that okay with you?"

Normalizing substance use: "Some people who suffer from anxiety self-medicate with alcohol to help them cope. Does this describe your situation?"

Overestimating the amount: "How many beers can you drink before you feel high? Is it closer to 24 or 12?"

Abuse of prescription medications: Red flags

In cases of suspected abuse of prescription medications, it is helpful to be alert to indicators of potentially problematic use. Abuse of prescribed medications may be encountered, for example, when treating a patient with an anxiety disorder with benzodiazepines or when treating a patient with chronic pain with opioids.

Signs that suggest problematic prescription drug use include:

  •  running out of medications early, presenting as:
    • multiple dose escalations with no evidence of benefit
    • multiple episodes of prescription "loss"
    • "borrowing" from family and friends
    • seeking prescriptions from multiple sources
  • deterioration in functioning
  • refusal to consider other treatment iptions despite lack of benefit

Psychiatric interviewing series

David Goldbloom and Nancy McNaughton demonstrate clinical interviewing situations.

Psychiatry in primary care toolkit

The Psychiatry in Primary Care App has been decommissioned. 

The revised print version of Psychiatry in Primary Care is avaible through the CAMH store. 

We have posted a number of revised chapters from the book in Treating Conditions and Disorders in the new Professionals section of