REVIEW OF: Gouverneur A et al, Br J Clin Pharmacol 2021;87:3971–3977

STUDY TYPE: Retrospective analysis

Sleepwalking and sleep-eating are common parasomnias, also known as somnambulism and sleep-related eating disorder. Both can be side effects of benzos, z-hypnotics, and—rarely—antidepressants. This review looked at parasomnias’ association with antipsychotics and lithium.

The authors used a World Health Organization database of suspected adverse drug reactions, which contains reports by physicians dating back to 1978. Lacking a control group, they compared the rate of parasomnias in the database with that in the general population to see if there was any disproportional reporting for patients on atypical antipsychotics or lithium.

They presented their data in terms of the proportional reporting ratio (PRR) for each medication—where a PRR over 1 means the parasomnia might be associated with the medication. As expected, the highest PRR by far was for the benzodiazepines and z-drugs, together at 60.51. The PRRs were also elevated for the atypical antipsychotics at 3.44 (CI 3.13–3.78) and lithium at 2.03 (CI 1.22–3.37). First-generation antipsychotics did not show a significant PRR at 0.99 (0.68–1.44), while antidepressants clocked in at 3.01 (CI 2.76–3.28). Atypical antipsychotics with the highest PRRs were quetiapine at 12.50 (CI 11.06–14.13), lurasidone at 7.00 (CI 3.97–12.34), olanzapine at 3.23 (CI 2.50–4.17), and aripiprazole at 2.89 (CI 2.17–3.83). Of the atypical antipsychotics, nearly all had a significant PRR except for risperidone, paliperidone, and clozapine.

The main weakness here is that data of this type are meant to find associations but cannot confirm them. Also, the results do not tell us how common the problem is, as mild cases are usually not reported to these kinds of databases.

TCPR’S Take
Although benzodiazepines and z-hypnotics are the medications that are most likely to cause parasomnias, these sleep problems may also occur on antidepressants, lithium, and most atypical antipsychotics.