Partial K-Complex Recovery Following Short-Term Abstinence in Individuals with Alcohol Use Disorder

The K-complex (KC) is a brain potential characteristic of nonrapid eye movement (NREM) sleep resulting from the synchronous activity of a large population of neurons and hypothesized to reflect brain integrity. KC amplitude is lower in individuals with alcohol use disorder (AUD) compared with age-matched controls, but its recovery with short-term abstinence has not been studied. Therefore, we investigated whether the KC shows significant recovery over the first 4 months of abstinence in individuals with AUD.

A total of 16 recently abstinent AUD individuals (46.6 ± 9.3 years) and 13 gender and age-matched healthy controls (41.6 ± 8.3 years) were studied on 3 occasions: the Initial session was within 1 month of the AUD individuals' last drink, then 1 and 3 months later. Overnight electroencephalogram was recorded while participants were presented with tones during stage 2 NREM sleep to elicit KCs.

At the Initial session, AUD participants showed significantly lower KC amplitude and incidence compared with controls. In the AUD individuals, KC amplitude increased significantly from the Initial to the 1-month session. KC incidence showed a marginally significant increase. Neither KC amplitude nor incidence changed from the 1-month to the 3-month session. No changes in KC amplitude or incidence across sessions were observed in the control group.

Our results demonstrate partial KC recovery during the first 2 months of abstinence. This recovery is consistent with the time course of structural brain recovery in abstinent AUD individuals demonstrated by recent neuroimaging results.