Sleep disorders and sleep deprivation leave different traces in the brain, study shows

About 20% to 35% of the population suffers from chronic sleep disorders—and up to half of all people in older age. Moreover, almost every teenager or adult has experienced short-term sleep deprivation at some point. There are many reasons for not getting enough sleep, whether it be partying, a long day at work, caring for relatives, or simply whiling away time on smartphones.

In a recent meta-study, Jülich researchers have now been able to show that the brain regions involved in the short-term and long-term conditions differ significantly. The results of the study were published in the journal JAMA Psychiatry.

“Poor sleep is one of the most important—but changeable—risk factors for mental illnesses in adolescents and older people,” says Jülich researcher and Privatdozent Dr. Masoud Tahmasian, who coordinated the study. In contrast, long-term pathological sleep disorders, such as insomnia, obstructive sleep apnea, narcolepsy, and short-term sleep deprivation, are located in different parts of the brain.

Lack of sleep has negative impact

Gerion Reimann, one of the lead authors of the study, who wrote his master’s thesis on this topic at the Jülich Institute of Neuroscience and Medicine (INM-7), says, “The symptoms of sleep deprivation are similar during the day. Anyone who has ever slept poorly or not had enough sleep will know how you often feel a bit grumpy—or unable to perform tasks well due to your attention and reaction times being significantly impaired.”

Repeated instances of sleep deprivation can have much more serious consequences. Studies show that frequent sleep deprivation has an adverse effect on brain development, reduces the removal of harmful substances from the brain, decreases emotional stability, and causes a massive decline in working memory as well as a person’s performance at school or at work. “Chronic sleep disorders and a continual lack of sleep are also risk factors for various mental illnesses,” says Reimann.

Different brain structures detected

The Jülich researchers analyzed data from 231 brain studies. The studies examined and compared several groups—for example, patients suffering from chronic sleep disorders with healthy individuals, or healthy, well-rested test subjects with those suffering from sleep deprivation. The results show clear neural differences between the groups.

People with chronic sleep disorders showed changes in a region of the brain known as the “anterior cingulate cortex,” as well as in the right amygdala and in the hippocampus, one of the brain’s central hubs. These regions are involved in processing emotions, memories, decisions, and sensations, for example.

Reimann explains, “These abnormalities reflect common symptoms that occur during the day with various sleep disorders, such as exhaustion, memory problems, mood swings, and even depression. Whether the changes in the brain are the cause or a consequence of chronic sleep disorders remains to be seen.”

In contrast, short-term sleep deprivation was associated with changes in the right thalamus, a brain region responsible for temperature regulation, movement, and the perception of pain. “This corresponds with the symptoms of short-term sleep deprivation,” says Reimann. “You are less attentive, restricted in your actions, and often feel the cold more easily.”

Important findings for future studies

“We were thus able to show for the first time that there are no overlapping brain regions between the two groups,” says Reimann. “This is important for future studies. We can now focus on the precise structural and functional regions and networks that are representative of the respective sleep disorder,” he emphasizes.

“Individual sleep disorders have previously been considered separately from one another. Now we can also address questions about chronic sleep disorders in transdiagnostic studies—in other words, we can examine several findings at the same time,” adds Tahmasian.

The new findings might also pave the way for more targeted therapies and preventive measures. “Many patients who suffer from insomnia—or chronic sleep disorders in general—also have an increased risk of depression, anxiety, and other mental disorders, as well as Alzheimer’s and other forms of dementia,” explains Reimann.

“Now that we know which brain regions are involved, we can investigate in more detail the effects of non-pharmacological therapies, such as cognitive behavioral therapy or continuous positive airway pressure (CPAP) therapy, in comparison to pharmacological treatments for various sleep disorders,” he adds.