Electrophysiological and Neuropsychological Indices of Cognitive Dysfunction in Patients with Chronic Insomnia and Severe Benzodiazepine Use Disorder

Benzodiazepine (BDZ) misuse is a growing health problem, with 1-2% of patients under BDZ treatment meeting the criteria for use disorder or dependence. Although BDZ addiction potential has been known for decades, much remains unknown its effects on brain functions. The aim of this study was to assess the neuropsychological and neurophysiological profile of a group of chronic insomniacs taking long-term high doses of benzodiazepine. We recruited 17 consecutive patients admitted to our third-level Sleep Medicine Unit for drug discontinuation (7 males, mean age 49.2 +/- 11.2 years, mean education 13.7 +/- 3.9 years, mean daily diazepam-equivalent BDZ: 238.1 +/- 84.5 mg) and 17 gender/age-matched healthy controls (7 males, mean age 46.8 +/- 14.1 years, mean education 13.5 +/- 4.5 years). We performed a full neuropsychological evaluation of all subjects and recorded their scalp event-related potentials (Mismatch-Passive Oddball-Paradigm and Active Oddball P300 Paradigm). Patients with chronic insomnia and BDZ use disorder showed a profound frontal lobe executive dysfunction with significant impairment in the cognitive flexibility domain, in face of a preserved working, short and long-term memory. In patients, P300 amplitude tended to be smaller, mainly over the frontal regions, compared to controls. BDZ use disorder has a severe cognitive impact on chronic insomnia patients. Long-term high-dose BDZ intake should be carefully evaluated and managed by clinicians in this specific patient population, especially in relation to risky activities.

Automated summary

The study aimed to evaluate the neuropsychological and neurophysiological profile of chronic insomniacs taking long-term high doses of benzodiazepine. The results showed that patients with chronic insomnia and benzodiazepine use disorder exhibited significant frontal lobe executive dysfunction, particularly in the cognitive flexibility domain, while their working memory, short-term memory, and long-term memory were relatively preserved. Compared to the control group, patients had a decrease in P300 amplitude, mainly in the frontal regions. Therefore, careful evaluation and management of long-term high-dose benzodiazepine intake should be considered for this specific patient population, especially regarding risky activities.