University of California Irvine investigators spotlight links and propose further systematic examination into the molecular underpinnings.
Circadian rhythm disruption is found to be common among mental disorders, according to investigators from the University of California Irvine (UC Irvine).
“Circadian rhythms play a fundamental role in all biological systems at all scales, from molecules to populations,” Pierre Baldi, UC Irvine distinguished professor of computer science, said in a statement. “Our analysis found that circadian rhythm disruption is a factor that broadly overlaps the entire spectrum of mental health disorders.”
In the study published in Translational Psychiatry, the investigators hypothesized that circadian rhythm disorder is a psychopathy factor that is shared by various mental disorders, aiming to research its molecular foundation to hopefully aid in discovering better therapies and treatments.
Circadian rhythm regulates the body’s biological processes and physiological activity during each day, synchronizing to a 24-hour light/dark cycle, according to the statement.
It influences when individuals need to sleep and when they are awake, but it also manages body temperature maintenance, the consolidation of memories, and hormone production and release.
“The telltale sign of circadian rhythm disruption, a problem with sleep, was present in each disorder,” Amal Alachkar, a professor of teaching in UCI's Department of Pharmaceutical Sciences, said in the statement. “While our focus was on widely known conditions including autism, [attention-deficit/hyperactive disorder], and bipolar disorder, we argue that the [circadian rhythm disorder] psychopathology factor hypothesis can be generalized to other mental health issues, such as obsessive-compulsive disorder, anorexia nervosa, bulimia nervosa, food addiction, and Parkinson disease.”
Circadian rhythm is sensitive to dark and light cues, so it can be easily disrupted by light exposure, but the level of disruptions was age- and sex-dependent. For example, fetuses and pregnant women can experience clinical effects from chronic stress and circadian rhythm disorder.
An association was seen between circadian rhythms and mental disorders based on sex, with disorders, such as Tourette syndrome more present in primary males and Alzheimer disease more common in females by a ratio of approximately two-third to one-third, investigators said.
Additionally, age is another important factor, because circadian rhythm disorder can affect neurodevelopment in early life, as well as leading to the onset of aging-related mental disorder among the elderly, they said.
Further examination is needed to determine if the circadian rhythm is a key player in the origin and onset of mental health disorders or if it is a self-reinforcing symptom in the progression of the disease, investigators said.
They suggested further examination of circadian rhythm disorder at the molecular level using metabolomic and transcriptomic technologies in mouse models.
“This will be a high-throughput process with researchers acquiring samples from healthy and diseased subjects every few hours along the circadian cycle,” Baldi said. “This approach can be applied with limitations in humans, since only serum samples can really be used, but it could be applied on a large scale in animal models, particularly mice, by sampling tissues from different brain areas and different organs, in addition to serum.”
Conducting experiments in a systematic way before and during disease progression could help identify potential biomarkers, causal relationships, and novel therapeutic targets and avenues, investigators said.
Circadian rhythm disruption found to be common among mental health disorders. News release. Science Daily. September 1, 2022. Accessed September 2, 2022. https://www.sciencedaily.com/releases/2022/09/220901200635.htm