Most people know that drunken sleep is the worst sleep. Even if excessive alcohol consumption causes one to “pass out,” it is seriously detrimental to sleep quality. A study published early this year determined that the more a person drank, the faster they were able to fall asleep. Then, despite the amount of alcohol consumed, the participants experienced deep sleep during the first half of the night. However, researchers also found that sleep disruption, or waking after falling asleep, increased during the second half of the night.

Now, researchers at Boston University School of Medicine (BUSM) are looking at how this alcohol-related sleep disruption actually happens. According to an article published in the online journal, Behavioral Brain Research, this disruption of the sleep cycle can occur in people who are actively drinking, suffering from withdrawal, or even when fully abstaining.

“Sleep-wake disturbances can last for months, or even years, after someone stops drinking, which indicates that chronic alcohol abuse could cause long-term negative effects on sleep,” said the article’s senior author, Subial Datta, BUSM professor of psychiatry and neurology.

The article explains how chronic alcohol use leads to dysfunction of cholinergic cells (cells that synthesize neurotransmitter acetylcholine) in an area of the brain stem involved in regulating many aspects of sleep. The disruption in the normal sleep cycle occurs as the activity of chemicals that excite neurons in the brain increases.

The article goes on to mention that although significant progress has been made in identifying the health risks of alcohol abuse and addiction, the underlying neurobiological mechanisms that lead to sleep-wake disorders related to alcohol are poorly understood. As a result, Datta notes that more research is needed to identify exactly how these neurological changes are happening so that scientists may be able to create medications to treat alcohol-related sleep disorders in the future.