Few Studies Adequately Report Adverse Events in CBT for Insomnia

Behavioral therapy
Cognitive behavioral therapy is the first line treatment for insomnia, but studies have reported potential negative effects. This review aims to understand the extent to which adverse events are monitored for and reported in trial literature.

Only about 7% of clinical trials that address cognitive behavioral therapy (CBT) for insomnia adequately report adverse events, according to a clinical review published in Sleep Medicine Reviews.

CBT is the first-line treatment for insomnia. However, not much attention is given to the treatment’s negative effects. CBT is presumed safer than pharmacological treatment, but, some patients develop new symptoms or experience an exacerbation of existing symptoms.

Researchers from University of Oxford’s Sleep and Circadian Neuroscience Institute investigated the extent to which these and other adverse events are monitored and reported.

The researchers identified randomized controlled trials related to CBT and insomnia from the PsychInfo, CINAHL, Medline, EMBASE, AMED, and Cochrane databases from inception until March 31, 2019. The researchers included studies that used adults age 18 and over with an insomnia disorder that identified CBT as an intervention, among other criteria. Out of 2,790 possible results, 99 studies were reviewed.

The researchers found that 32% of the studies addressed adverse events. Most of these mentioned that adverse events occurred, but about half of them did not define how they defined or collected adverse event data. Most notably, only 7.1% of studies (only 7 studies) met all the researchers’ criteria for reporting adverse events.

The researchers ultimately found CBT-Insomnia studies “have paid limited attention to the measurement and reporting of adverse events.” They suspect this issue is improving over time as about half the studies that reported adverse events took place between 2015 and 2019.

A limitation of this review is that it only included studies where CBT for insomnia was compared to a nonactive or minimal intervention control group. The researchers extracted data on the definition of adverse events only if the study predefined adverse event classification before reporting results. Conclusions are limited to the extent of adverse event reporting as opposed to quality.

“Should adverse events become a better understood part of CBTI, clinicians may

consider planning in extra time during initial sessions in order to discuss possible negative effects of treatment, to manage treatment expectations as well as problem-solve possible barriers to engagement,” the researchers concluded. “Regular review over the course of treatment may also help structure and tailor support when needed. From a research perspective, it may also be fruitful to develop and test strategies to mitigate minor adverse events (eg: countermeasures against fatigue and sleepiness) and improve patient adherence/engagement.”


Condon HE, Maurer LF, Kyle SD. Reporting of adverse events in cognitive behavioural therapy for insomnia: A systematic examination of randomised controlled trials. Sleep Med Rev. Published online November, 29, 2020. doi:10.1016/j.smrv.2020.101412