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Mental health disorders and circadian rhythm disruption are closely associated, according to a new analysis. NICK VEASEY/SCIENCE PHOTO LIBRARY/Getty Images

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  • A new study finds a striking association between people who have sleep difficulties and people who have mental health conditions.
  • The authors of the study focused primarily on autism, ADHD, and bipolar disorder, but believe their findings may also apply to other mental health issues as well.
  • Not getting enough sleep has previously been linked to a range of health issues, including mental health disorders.

Worldwide, only 1 in 10 people report “sleeping extremely well”, according to Philips’ 2019 Global Sleep Survey. Most adults in that survey, about 62%, reported sleeping “somewhat or not at all well.”

Such sleeping problems are associated with various mental health disorders such as depression, anxiety, bipolar disorder, attention deficit hyperactivity disorder (ADHD), and bipolar disorder.

Of the 300 million people globally who have depression, research suggests that 75% also have insomnia.

A new study from researchers at the University of California, Irvine (UCI) explores the connection between difficulties sleeping and a range of mental health disorders.

Amal Alachkar, Ph.D., the study’s lead author, said in a news release, “The telltale sign of circadian rhythm disruption — a problem with sleep — was present in each disorder.”

“While our focus was on widely known conditions including autism, ADHD, and bipolar disorder, we argue that the CRD psychopathology factor hypothesis can be generalized to other mental health issues, such as obsessive-compulsive disorder, anorexia nervosa, bulimia nervosa, food addiction, and Parkinson’s disease,” Dr. Alachkar continued.

The results were recently published in Translational Psychiatry.

For the study, researchers examined the link between CRD and a number of different mental disorders and mental health conditions.

  • Autism spectrum disorder (ASD): The National Autism Society describes autism as “a lifelong developmental disability which affects how people communicate and interact with the world.” (Autism is not universally considered a mental disorder.)
  • Attention deficit hyperactivity disorder (ADHD): ADHD is a condition with which a person, often a child, finds it difficult to focus, exhibits inappropriate physical movement, and acts impulsively without thinking through the consequences.
  • Bipolar disorder (BPD): People with bipolar disorders experience extreme mood swings lasting days or weeks, marked by periods of abnormal happiness or irritability that alternate with periods of depressive sadness.
  • Tourette syndrome: Tourette syndrome is a neurological disorder in which a person produces “tics”: sudden, rapid, repetitive, and unwanted movements or vocal sounds.
  • Schizophrenia spectrum disorder: Schizophrenia alters a person’s thinking, emotional state, and behavior to an extent that it may seem to others as if they have lost touch with reality.
  • Major depressive disorder (MDD): MDD refers to a state in which a person experiences prolonged bouts of depression most of the time over a period of weeks, interfering with one’s ability to function.
  • Anxiety disorder: Anxiety disorder causes a person to live in a persistent state of anxiousness or dread.
  • Alzheimer’s disease (AD): With the progression of Alzheimer’s disease, a person’s memory and thinking become severely degraded over a period of time.

“An interesting issue that we explored is the interplay of circadian rhythms and mental disorders with sex,” senior author Pierre Baldi, Ph.D., author of the study and distinguished professor of computer science at UCI, said in a news release. “For instance, Tourette syndrome is present primarily in males, and Alzheimer’s disease is more common in females by a ratio of roughly two-thirds to one-third.”

The body’s internal, 24-hour — or circadian — clock regulates important daily routines such as sleeping and waking, body temperature, eating, digesting, and hormonal activity.

The researchers reviewed existing literature on circadian rhythm disruption (CRD) or sleep disruption and noted that CRD early in life may affect neurodevelopment and promote aging-related mental health disorders later on.

According to a news release, researchers hypothesized that “CRD is a psychopathology factor shared by a broad range of mental illnesses.” The researchers believe that studying the molecular foundation of CRD could unlock better therapies and treatments for various mental disorders.

Jonathan Cedernaes, Ph.D., a sleep specialist at Uppsala Universitet who was not involved in the study, told Medical News Today:

“This review highlights the fact that sleep disorders and circadian disruption are very common in mental disorders. Based on animal data, it can also be speculated that circadian disruption during pregnancy can impair outcomes of the offspring, including for mental health or psychiatric disease risk.”

Stress or mental health issues can affect a person’s sleep-wake cycle, as can night shift work, changing time zones, or simply being a “night owl.”

“It is important to note there is [an] inter-individual variation in our sleep-wake patterns, so not everyone looks the same,” Dr. Cedernaes said. “This variation is partly tied to biological preference, but also in part due to work or social constraints.”

Alicia Roth, Ph.D., of Cleveland Clinic’s Sleep Disorders Center, not involved in the study, told MNT:

“It’s interesting to examine the link between circadian rhythm disorders and mental health, particularly in persons with delayed circadian rhythm disorder — i.e., extreme night owls.”

“These are usually adolescents and young adults. With a delayed rhythm, their preferred sleep schedule (i.e., early morning bedtime, late morning [or] early afternoon wake time) is incongruent with what’s socially acceptable.”

Dr. Roth suggests that mental health issues may be related to the stigmatization such people experience for their schedules.

“In addition to the biological influences, I think that stigma plays a large role in persons with a delayed rhythm developing adverse psychological outcomes related to their preferred sleep schedule.”

– Alicia Roth, PhD

An obvious question that remains unanswered by the study is whether CRD causes mental health issues or if mental health issues lead to CRD, or if they are both tied independently to similar root causes.

The authors suggest that future research might answer this question through an investigation of CRD on a molecular level. They propose exploring gene expression and metabolomic technologies in mice as a place to start.

“This will be a high-throughput process, with researchers acquiring samples from healthy and diseased subjects every few hours along the circadian cycle,” Prof 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,” he continued.

If a causal connection between CRD and mental health is supported by further research, a person may one day avoid mental health issues by staying in sync with their own circadian rhythm.

“One can keep a diary of their sleep-wake schedule. This can make it clear if the schedule is too erratic, and possibly help one to improve it,” Dr. Cedernaes suggested.

According to Dr. Roth, if people are left to their own devices without responsibilities (i.e., no school, kids, work, or need to be on any schedule), how well do they sleep, and what time do they naturally fall asleep and wake up?

“It’s important to try to capture what a person’s body wants to do when limitations and scheduling is removed,” Dr. Roth said.

“A person may [also] have a delayed rhythm, but their sleep timing works for them because they have [in]flexible school, work, or life commitments,” she added. “Often they just need validation that their ‘unusual’ sleep times are fine as long as they are getting enough sleep and functioning as they would like.”

According to Dr. Cedernaes, “ideally, one would, for example, wake up and go to bed the same time every day, and also eat the same time every day.”

“We also encourage basic good sleep habits,” Dr. Roth said. “The most important being: do not try to force yourself to sleep, only get into bed when you feel sleepy, and don’t linger in bed in the morning and snooze.”