Screening and assessment of quetiapine and other antipsychotic use

Ask all new patients routinely and others (adolescents and adults) opportunistically and periodically about medication use, as part of a general screen for disorders of substance use and gambling; these disorders are common (and often co-exist) and patients are reluctant to disclose them, often due to fear of stigma. Screening and assessment of substance use and addictive behaviours outlines history-taking (including use of the ASSIST-Lite tool), examination, and investigations that should be considered in a broad review of substance use and addictive behaviour. Consider an electrocardiogram (ECG) to detect QTc prolongation in patients taking high doses of quetiapine.

If quetiapine or other antipsychotic use is identified, specific questions to assess use in more detail include:

• duration and dosage—prolonged use of recommended or higher doses can result in withdrawal symptoms on stopping
• use of any other substances (alcohol, over-the-counter medications, complementary therapies, other prescribed or illicit drugs) to assess risk of fatal sedation or other dangerous interactions; see Quetiapine poisoning for clinical presentation of central nervous system, cardiac and anticholinergic effects
• factors that precipitate or perpetuate use—assess for undertreated anxiety¹, untreated or undertreated psychosis, difficulties with regulation of emotional distress (eg in personality disorder), insomnia and other disorders of substance use
• withdrawal symptoms experienced on previous attempts to reduce usage.

Symptoms reported after abrupt stopping of quetiapine include dysphoria, anxiety and irritability, palpitations, tachycardia, dizziness, light-headedness, hypertension, nausea and vomiting, insomnia, sweating, movement disorders, craving, fatigue and headacheMonahan, 2021.