Sleep And Anxiety: Understanding The Vicious Cycle & “Why Can’t I Sleep?”

Quick Summary

• There is a strong bidirectional, or two-way, relationship between insomnia and anxiety. Not only does anxiety disrupt sleep, but insomnia is also a major predictor for the development of anxiety disorders (Palagini et al., 2024).

• The brains of people with insomnia show changes that overlap with those seen in anxiety, including an overactive fear center (the amygdala) and an underactive emotional regulation center (the prefrontal cortex).

• Biological mechanisms like the disruption of the stress hormone cortisol and a trait called "anxiety sensitivity" - the fear of anxiety's physical symptoms - create a state of high alert that makes sleep difficult.

• Treating an anxiety disorder often does not fully resolve co-occurring insomnia. Evidence suggests that insomnia requires its own targeted treatment, like Cognitive Behavioral Therapy for Insomnia (CBT-I), which can in turn reduce the severity of anxiety symptoms.

Sleep And Anxiety Disorders: An Overview

It’s a frustratingly common experience: you’re lying in bed, exhausted, but your mind refuses to switch off.

Worries about work, family, or health race through your head, and with every passing minute, a new anxiety joins the list: “Why can’t I fall asleep? I’m going to be a zombie tomorrow.”

This cycle, where anxiety prevents sleep and sleep disruption fuels anxiety, is more than just a bad night. It’s a well-documented physiological and psychological loop that can be difficult to break.

A comprehensive 2024 systematic review published in Neuroscience Applied examined the deep connection between insomnia and a range of anxiety-related disorders, confirming what many people feel intuitively: the link is powerful, complex, and affects both the brain and body (Palagini et al., 2024).

Understanding this connection is the first step toward finding effective strategies to quiet your mind and finally get the restorative sleep you need. So what exactly is the link between anxiety and insomnia?

What Is the Link Between Anxiety and Insomnia?

The link between anxiety and insomnia is a strong, bidirectional relationship where each condition can cause or worsen the other.

People with insomnia have a significantly higher risk of developing an anxiety disorder, and conversely, the vast majority of people with an anxiety disorder also experience insomnia symptoms severe enough to be diagnosed (Palagini et al., 2024).

This echos the broader relationship between sleep and mental health.

For a long time, insomnia was often viewed as just another symptom of anxiety. The thinking was that if you treated the anxiety, the sleep problems would naturally disappear. However, a growing body of research shows this isn't the case.

Insomnia is now understood as a distinct disorder that often requires its own targeted treatment, even when it co-occurs with anxiety (Palagini et al., 2024).

The evidence for insomnia as a direct risk factor for anxiety is compelling.

A large-scale meta-analysis, a type of study that combines the results of many previous scientific studies, found that individuals with insomnia were more than three times as likely to develop an anxiety-related disorder later on (Hertenstein et al., 2019).

Further supporting this causal link, a two-sample Mendelian randomization study, a method that uses genetic data to determine cause and effect, found that a genetic predisposition for insomnia statistically predicted the onset of anxiety (Zhou et al., 2022).

This suggests that the sleep disruption itself plays an active role in creating the conditions for anxiety to take hold.

So, if you are struggling with both, which one should you address? The answer is increasingly clear: both. But how exactly does a lack of sleep create such a fertile ground for worry and fear?

Why Does a Lack of Sleep Make Anxiety Worse?

A lack of sleep makes anxiety worse by disrupting the brain's emotional control centers, altering key the brain's chemical messenger and hormonal systems, and reinforcing the mental habits of worry and rumination.

This creates a state of hyperarousal, where the brain’s “fight or flight” system gets stuck in the “on” position, making it difficult to relax during the day and nearly impossible to sleep at night (Palagini et al., 2024).

How does poor sleep change the anxious brain?

Poor sleep fundamentally alters the balance between key emotional centers in the brain, making you more reactive to stress.

The two main areas involved are:
1) the amygdala, the brain's primitive alarm system, and

2) the prefrontal cortex, the more evolved area responsible for rational thinking and emotional control.

• Overactive Amygdala: The amygdala is responsible for detecting threats and triggering fear responses. In people with insomnia, neuroimaging studies show the amygdala is hyperactive, much like it is in those with anxiety disorders (Palagini et al., 2024). After just one night of poor sleep, this brain region can become significantly more reactive, causing you to perceive neutral situations as threatening (Yoo et al., 2007).

• Underactive Prefrontal Cortex (PFC): The PFC acts as the "brakes" for the amygdala, helping you regulate your emotional responses and make logical decisions. Sleep is essential for the PFC to function properly. When you're sleep-deprived, the connection between the PFC and the amygdala weakens. Essentially, the brain's alarm system is ringing loudly with no one in the control tower to turn it off.

This neurological state also impairs a process called fear extinction memory, the brain's ability to learn that something that was once dangerous is now safe. Good quality sleep, particularly REM sleep, helps strengthen and lock in these memories.

When sleep is disrupted, the brain struggles to update its safety information, which can cause fears and anxieties to persist and worsen over time (Palagini et al., 2024).

What is the role of the stress hormone cortisol?

The stress hormone cortisol plays a critical role in both sleep regulation and anxiety. In a healthy cycle, cortisol levels are highest in the morning to promote alertness and gradually decrease throughout the day, reaching their lowest point at night to facilitate sleep (Spiegel et al., 1999).

Poor sleep and chronic anxiety disrupt this natural rhythm.

Both conditions are associated with elevated cortisol levels in the evening, which contributes to a state of physiological arousal that makes it very difficult to fall asleep (Rohrs et al., 2018).

Studies have shown that individuals with GAD and OCD often exhibit this pattern of cortisol dysregulation, which helps explain the biological underpinnings of their sleep difficulties (Mantella et al., 2008; Kluge et al., 2007).

How Does 'Anxiety Sensitivity' Affect Sleep?

Anxiety sensitivity is a specific trait defined as the fear of anxiety-related physical sensations.

People with high anxiety sensitivity tend to misinterpret normal bodily feelings - like a racing heart or a tight chest - as signs of a looming catastrophe, such as a heart attack or losing control.

This fear of the body's own anxiety response is a powerful predictor of both anxiety disorders and sleep problems (Rohrs et al., 2018).

When you are afraid of your own physical sensations, you become extra alert and watchful, constantly scanning your body for "symptoms." This state of high alert is the direct opposite of the mental and physical relaxation required to fall asleep.

In fact, one study found that anxiety sensitivity was a more significant predictor of sleep problems than a person's specific anxiety diagnosis (Baker et al., 2017).

How Does Insomnia Affect Specific Anxiety Disorders?

While insomnia is a common thread, it manifests differently and has unique relationships depending on the specific anxiety disorder. The 2024 review by Palagini and colleagues synthesized the evidence across several major conditions, revealing just how deeply intertwined sleep and anxiety are.

What is the connection between Generalized Anxiety Disorder (GAD) and insomnia?

Insomnia is a key symptom used to diagnose GAD and is exceptionally common, affecting more than half of all patients with the disorder. GAD is characterized by excessive, uncontrollable worry, and this mental state is a major barrier to sleep.

Studies show that between 51% and 68% of individuals with GAD report significant insomnia symptoms (Brenes et al., 2009).

Objective sleep studies using polysomnography, a comprehensive test that measures brain waves and body functions during sleep, confirm these reports. People with GAD tend to take longer to fall asleep and have less total sleep time compared to healthy individuals (Cox & Olatunji, 2016).

The severity of the insomnia is often linked to the severity of the GAD symptoms, and it can also increase the risk of developing other conditions, such as depression (Palagini et al., 2024).

What are nocturnal panic attacks?

A nocturnal panic attack is an episode where a person wakes abruptly from sleep in a state of intense fear, accompanied by strong physical symptoms like a racing heart, shortness of breath, and sweating.

These attacks are not caused by nightmares and often occur during the transition into deeper stages of non-REM sleep (Landry et al., 2002).

The majority of people with Panic Disorder - between 65% and 70% - report experiencing at least one nocturnal panic attack (Mellman & Uhde, 1989). The experience can be so frightening that it creates a conditioned, or learnt fear of sleep itself, leading to dread as bedtime approaches and, in some cases, severe avoidance of sleep (Singareddy & Uhde, 2009).

Are Social Anxiety and OCD also linked to insomnia?

Yes, both Social Anxiety Disorder (SAD) and Obsessive-Compulsive Disorder (OCD) show a strong connection to insomnia.

In SAD, studies have found that up to 70% of patients report insomnia symptoms, often driven by rumination about social encounters (Raffray et al., 2011).

In OCD, the link is particularly strong, with insomnia often worsening as OCD symptoms become more severe (Raines et al., 2015).

The intrusive thoughts (obsessions) and repetitive behaviors (compulsions) can directly interfere with sleep.

Furthermore, a significant number of people with OCD also have Delayed Sleep Phase Disorder (DSPD), a condition where the internal body clock is shifted much later than normal, making it difficult to fall asleep at a conventional time (Mukhopadhyay et al., 2008).

What Is the Best Way to Treat Insomnia When You Have Anxiety?

The best approach to treating co-occurring insomnia and anxiety is to address both conditions, with a particular focus on interventions that directly target the sleep problem.

Relying solely on anxiety treatment is often not enough to fix chronic insomnia, whereas treating the insomnia can lead to improvements in both sleep and anxiety.

Should you treat the anxiety or the insomnia first?

Evidence suggests that directly treating insomnia is a critical, and sometimes primary, step.

While treating anxiety can sometimes improve sleep, a significant number of patients continue to suffer from insomnia even after their anxiety is well-managed (Palagini et al., 2024).

Conversely, treating insomnia often has the added benefit of reducing anxiety symptoms.

One study on patients with both GAD and insomnia found that while starting with GAD treatment was effective, adding insomnia-specific treatment resulted in further enhancements to both sleep quality and anxiety levels (Belleville et al., 2016). This supports an integrated approach where insomnia is never treated as an afterthought.

What are the recommended treatments for insomnia?

The gold-standard, first-line treatment for chronic insomnia is Cognitive Behavioral Therapy for Insomnia (CBT-I). This is a structured, non-medication program that helps you understand how the sleep-wake system actually works, then identify and change behaviors and beliefs about sleep that are interfering with your sleep and keeping the vicious cycle of insomnia going.

CBT-I has proven highly effective for people with co-occurring anxiety disorders. It typically includes several components:

• Cognitive Restructuring: Challenging and changing the anxious thoughts and unhelpful beliefs a person has about sleep (e.g., "I must get 8 hours of sleep or I won't function") that can be increasing anxiety about sleep, or maintaining behaviors that disrupt the sleep-wake system.

• Sleep Consolidation Training (aka Sleep Restriction): Temporarily limiting time in bed to more closely match the actual amount of time you are sleeping, which increases the physiological drive for sleep and improves the depth and quality of sleep.

• Stimulus Control: Re-associating your bed and bedroom with sleep by establishing strict rules, such as only using the bed for sleep and intimacy and getting out of bed if you can't fall asleep.

• Relaxation Techniques: Learning methods like deep breathing, progressive muscle relaxation, or mindfulness to calm the body's hyperaroused state.

What Practical Steps Can I Take to Improve Sleep and Anxiety?

Professional guidance is recommended for chronic issues with anxiety or insomnia. We do not suggest sleep hygiene advice, wind down routines nor relaxation techniques for people with a history of anxiety or insomnia unless it’s under supervision of a professional. Why? The nature of anxiety means that well-meaning sleep advice can backfire and create more vicious cycles of anxiety and sleeplessness. Therefore or only advice:

• Talk to a Professional: Your family doctor or a trusted healthcare professional can help you determine the best course of action and discuss whether non-drug therapy and/or medication might be appropriate for you

• Talk to a qualified sleep psychologist: A sleep psychologist can provide evidence-based therapies like CBT for your anxiety disorder and CBT-I for insomnia. Qualifications in behavioural sleep medicine, such as the DBSM, can give reassurance the sleep psychologist is properly trained and knowledgable.

Living with an anxiety disorder is challenging enough without the added burden of sleepless nights. By understanding the deep connection between the two and taking targeted steps to address both your mental health and your sleep, you can break the cycle and work toward a future of calmer days and more restful nights.

Concerned about your sleep? We always advocate talking to your primary care health provider in the first instance.

You can also talk to a NZ sleep clinic like The Better Sleep Clinic for sleep help. Whether it’s an Auckland sleep clinic, Wellington sleep clinic, Christchurch sleep clinic, Hamilton sleep clinic, New Plymouth sleep clinic or anywhere in NZ, we can help. We specialise in the recommended insomnia treatment - CBT for insomnia. We also have expertise in treating other sleep disorders such as treatments for circadian rhythm disorders such as delayed sleep phase disorder, nightmare disorder, and co-occuring mental health conditions.

Book an assessment (no referral required) or, if you have a specific question, enquire about treatment and get started addressing your sleep problems today.

Frequently Asked Questions About Anxiety and Insomnia

Q1: What is the relationship between anxiety and insomnia?

A1: The relationship between anxiety and insomnia is a strong, two-way street where each condition can cause and worsen the other. While anxiety is a well-known cause of sleep disruption, recent scientific reviews confirm that having insomnia is also a major predictor for developing an anxiety disorder in the future (Palagini et al., 2024). For this reason, insomnia is now viewed as a distinct disorder that often requires its own treatment, not just as a symptom of anxiety.

Q2: Can insomnia actually cause anxiety?

A2:  Yes, evidence strongly suggests that insomnia can directly contribute to the development of anxiety. For instance, a large-scale scientific review found that people with insomnia were more than three times as likely to develop an anxiety-related disorder (Hertenstein et al., 2019). Furthermore, a study using genetic data found that a predisposition for insomnia was a statistical predictor for the later onset of anxiety, reinforcing this causal link (Zhou et al., 2022).

Q3: Why does a lack of sleep make my anxiety worse?

A3: A lack of sleep worsens anxiety by disrupting the brain's emotional regulation systems, creating a state of "hyperarousal" where the body’s stress response is stuck in the 'on' position (Palagini et al., 2024). After just one night of poor sleep, the brain’s fear center, an area called the amygdala, becomes more reactive, while the prefrontal cortex, which is responsible for rational control, becomes less active. This imbalance makes you more likely to perceive neutral situations as threatening (Yoo et al., 2007).

Q4: How does the stress hormone cortisol affect sleep and anxiety?

A4: The stress hormone cortisol is a key biological factor linking sleep and anxiety. Normally, cortisol levels are highest in the morning to help you wake up and gradually decrease to their lowest point at night to allow for sleep (Spiegel et al., 1999). Both chronic anxiety and insomnia can disrupt this rhythm, leading to elevated cortisol levels in the evening. This hormonal imbalance promotes a state of physical alertness that makes it very difficult to fall asleep (Rohrs et al., 2018).

Q5: What is 'anxiety sensitivity' and how does it affect sleep?

A5: Anxiety sensitivity is the fear of the physical sensations of anxiety itself, such as a racing heart or shortness of breath. People with high anxiety sensitivity often misinterpret these normal bodily feelings as signs of a serious medical problem, which creates a cycle of fear (Rohrs et al., 2018). This constant self-monitoring and worry create a state of high alert that is the opposite of the relaxation needed for sleep. In fact, one study found this trait was a better predictor of sleep problems than a person's specific anxiety diagnosis (Baker et al., 2017).

Q6: Do people with Generalized Anxiety Disorder (GAD) have trouble sleeping?

A6: Yes, insomnia is a core diagnostic symptom of Generalized Anxiety Disorder (GAD), affecting more than half of all people with the condition. Studies show that between 51% and 68% of individuals with GAD report significant insomnia (Brenes et al., 2009). The uncontrollable worry that defines GAD is a major barrier to falling asleep, and objective sleep studies confirm that people with GAD take longer to fall asleep and get less total sleep than healthy individuals (Cox & Olatunji, 2016).

Q7: What are nocturnal panic attacks?

A7: A nocturnal panic attack is an episode where a person wakes up suddenly from sleep in a state of intense fear, often with powerful physical symptoms like a racing heart, sweating, and shortness of breath. These attacks are not triggered by nightmares and tend to happen during the transition from light to deeper stages of sleep (Landry et al., 2002). They are very common in people with Panic Disorder and can create a conditioned fear of sleep itself (Mellman & Uhde, 1989).

Q8: Should I treat my anxiety or my insomnia first?

A8: Evidence increasingly shows that insomnia should be treated directly, rather than assuming it will disappear once anxiety is managed. While treating anxiety can help sleep, many people continue to experience insomnia even after their anxiety symptoms improve (Palagini et al., 2024). Conversely, directly treating insomnia with methods like Cognitive Behavioral Therapy for Insomnia (CBT-I) has been shown to reduce the severity of anxiety symptoms, making it a critical part of a comprehensive treatment plan (Belleville et al., 2016).

References

Baker, A. W., Keshaviah, A., Goetter, E. M., Bui, E., Swee, M. B., Rosencrans, P. L., & Simon, N. M. (2017). Examining the Role of Anxiety Sensitivity in Sleep Dysfunction Across Anxiety Disorders. Behavioral Sleep Medicine, 15(3), 216–227.

Belleville, G., Ivers, H., Bélanger, L., Blais, F. C., & Morin, C. M. (2016). Sequential treatment of comorbid insomnia and generalized anxiety disorder. Journal of Clinical Psychology, 72(9), 880–896.

Brenes, G. A., Miller, M. E., Stanley, M. A., Williamson, J. D., Knudson, M., & McCall, W. V. (2009). Insomnia in older adults with generalized anxiety disorder. The American Journal of Geriatric Psychiatry, 17(6), 465–472.

Cox, R. C., & Olatunji, B. O. (2016). A systematic review of sleep disturbance in anxiety and related disorders. Journal of Anxiety Disorders, 37, 104–129.

Hertenstein, E., Feige, B., Gmeiner, T., Kienzler, C., Spiegelhalder, K., Johann, A., Jansson-Fröjmark, M., Palagini, L., Rücker, G., Riemann, D., & Baglioni, C. (2019). Insomnia as a predictor of mental disorders: a systematic review and meta-analysis. Sleep Medicine Reviews, 43, 96–105.

Kluge, M., Schüssler, P., Künzel, H. E., Dresler, M., Yassouridis, A., & Steiger, A. (2007). Increased nocturnal secretion of ACTH and cortisol in obsessive compulsive disorder. Journal of Psychiatric Research, 41(11), 928–933.

Landry, P., Marchand, L., Mainguy, N., Marchand, A., & Montplaisir, J. (2002). Electroencephalography during sleep of patients with nocturnal panic disorder. The Journal of Nervous and Mental Disease, 190(8), 559–562.

Mantella, R. C., Butters, M. A., Amico, J. A., Mazumdar, S., Rollman, B. L., Begley, A. E., Reynolds, C. F., & Lenze, E. J. (2008). Salivary cortisol is associated with diagnosis and severity of late-life generalized anxiety disorder. Psychoneuroendocrinology, 33(6), 773–781.

Mellman, T. A., & Uhde, T. W. (1989). Sleep panic attacks: new clinical findings and theoretical implications. American Journal of Psychiatry, 146(9), 1204–1207.

Mukhopadhyay, S., Fineberg, N. A., Drummond, L. M., Torres, A. R., Prakashi, P., de Menezes, G. B., Reddy, Y. C. J., & Fontenelle, L. F. (2008). Delayed sleep phase in severe obsessive-compulsive disorder: a systematic case-report survey. CNS Spectrums, 13(5), 406–413.

Palagini, L., Miniati, M., Caruso, V., Alfi, G., Geoffroy, P. A., Domschke, K., Riemann, D., Gemignani, A., & Pini, S. (2024). Insomnia, anxiety and related disorders: a systematic review on clinical and therapeutic perspective with potential mechanisms underlying their complex link. Neuroscience Applied, 3, 103936.

Raffray, T., Bond, T. L. Y., & Pelissolo, A. (2011). Correlates of insomnia in patients with social phobia: role of depression and anxiety. Psychiatry Research, 189(2), 315–317.

Raines, A. M., Walton, J. L., Wilson, C. S., & Schmidt, N. B. (2015). Obsessive-compulsive symptom dimensions and insomnia: The mediating role of anxiety sensitivity cognitive concerns. Psychiatry Research, 228(3), 368–372.

Rohrs, B., Gangewere, B., Kaplan, A., & Chopra, A. (2018). Anxiety, Obsessive-Compulsive, and Related Disorders. In A. S. G. Friedman (Ed.), Sleep and Neurologic Disease. Elsevier. 

Singareddy, R., & Uhde, T. W. (2009). Nocturnal sleep panic and depression: relationship to subjective sleep in panic disorder. Journal of Affective Disorders, 112(1-3), 262–266.

Spiegel, K., Leproult, R., & Van Cauter, E. (1999). Impact of sleep debt on metabolic and endocrine function. The Lancet, 354(9188), 1435–1439.

Yoo, S. S., Gujar, N., Hu, P., Jolesz, F. A., & Walker, M. P. (2007). The human emotional brain without sleep--a prefrontal amygdala disconnect. Current Biology, 17(20), R877–R878.

Zhou, F., Li, S., & Xu, H. (2022). Insomnia, sleep duration, and risk of anxiety: a two-sample Mendelian randomization study. Journal of Psychiatric Research, 155, 219–222.

Written By The Better Sleep Clinic

Reviewed By Dan Ford, Sleep Psychologist