When Nightmares Become a Clinical Concern

Nightmares are not just a fleeting inconvenience—they can have profound implications on mental health and overall well-being. Recent studies have suggested that nightmares are underdiagnosed and undertreated, even in sleep centers.^1,2

Because it is unlikely that patients will report nightmares without provocation, it is important for providers to inquire about nightmares. In fact, research recommends that sleep centers should include questions about nightmare frequency and distress as part of their diagnostic assessment.²

There is evidence in the literature that a considerable number of sleep-disordered patients are in need of nightmare counseling.² Why is this a clinical problem? Nightmares cause extreme distress for the patient and are associated with worse mental health outcomes, such as anxiety, depression, and suicidal ideation, all of which have significant implications for quality of life.³

Given their widespread impact and clinical significance, it’s crucial to look at the prevalence of nightmares, which patients are at risk, how we define nightmares clinically, and what treatment options are available.

Far More Than Just a Bad Dream

Nightmares are commonly experienced, and yet their phenomenology is not well understood. Several theories exist regarding the development of nightmares. The continuity hypothesis posits that dreaming reflects waking experiences, while the stress acceleration hypothesis suggests that early adversity increases emotional responses to stress, heightening the likelihood of nightmares later in life.⁴

The Affect Network Dysfunction model suggests that nightmares arise from both situational and dispositional emotional responses, linking emotional distress to nighttime experiences.⁵ Recently, an integrative model has been proposed, combining these theories to explain how psychological distress, maladaptive cognitive factors, and physiological responses lead to persistent nightmares.⁶

Clinically, nightmares are classified as a type of parasomnia—specifically, distressing and vivid dreams that provoke strong negative emotions, such as fear and anxiety. They typically occur during REM sleep and are characterized by the dreamer’s ability to remember them upon waking. Interestingly, the definition of nightmares has been debated over time, but they are now widely recognized as a significant sleep disturbance.

Prevalence and Comorbid Associations

Nightmares are surprisingly common. Research conducted in Norway found that approximately 66 percent of adults reported experiencing nightmares at some point in their lives, with around 19 percent experiencing them currently.⁷ This prevalence highlights how pervasive nightmares are in the general population.

They often lead to awakenings, which can create a vicious cycle of insomnia. Individuals may become preoccupied with the fear of having a nightmare, making it difficult for them to fall asleep initially. This anxiety can exacerbate the likelihood of experiencing nightmares, leading to further sleep disruptions.

Nightmares are common in the general population but their prevalence is even greater in certain subpopulations including military veterans, patients with post-traumatic stress disorder (PTSD), and patients with psychiatric conditions.^6,8-9 It is critical to understand how nightmares can be a standalone or comorbid clinical presentation that warrants attention.

Mental Health Conditions

Nightmares are associated with heightened symptoms of PTSD, depression, anxiety, and even suicidality. Notably, studies have shown that nightmares can occur even after controlling for other mental health symptoms, indicating their independent role in distress.

About 70 percent of adult psychiatric patients report recurrent nightmares, a figure significantly higher than the general population’s rate of up to 11 percent.⁶ This suggests that nightmares may serve as a symptom of underlying psychological distress, particularly in individuals with PTSD.

Nightmares are often a core symptom of PTSD. The DSM-5 outlines that individuals must experience intrusive symptoms related to a traumatic event, one of which may be recurrent nightmares.⁸ In fact, up to 96 percent of PTSD patients report experiencing nightmares, highlighting their significance in this population.⁹

Interestingly, trauma-related nightmares can persist even after successful trauma-focused treatment, suggesting that they may represent a separate clinical entity distinct from other PTSD symptoms.

Cognitive Decline

Recent studies have also indicated a relationship between persistent nightmares and cognitive decline. A 2022 study found that individuals experiencing weekly distressing dreams had a nearly fourfold increased risk of cognitive decline and a twofold increased risk of developing dementia.⁸

While the exact relationship between nightmares and cognitive decline remains unclear, it is believed that fragmented sleep caused by nightmares may play a significant role in this association.⁸

When Do Nightmares Become a Disorder?

Nightmare disorder is diagnosed when nightmares become clinically significant and persistent. The International Classification of Sleep Disorders outlines specific diagnostic criteria, including repeated occurrences of extended, extremely dysphoric, and well-remembered dreams that cause clinically significant distress or impairment in important areas of daily functioning.¹⁰

The DSM-5 categorizes the severity of nightmare disorder based on frequency:¹¹

• mild (less than one nightmare per week)
• moderate (at least one nightmare weekly)
• severe (nightly nightmares)

Duration is also a factor, with acute cases lasting less than a month and chronic cases persisting for six months or more.

Several risk factors are associated with nightmare disorder, including:¹²

• Age: Individuals under 50 are more likely to experience nightmares.
• Gender: Females report nightmares more frequently than males.
• Medication: Certain medications or withdrawal from them can trigger nightmares.
• Genetics: There may be a genetic predisposition for nightmares.
• Socioeconomic status and psychiatric diagnoses: Lower income and pre-existing mental health conditions increase the risk.
• Trauma: Experiencing traumatic events, like in military service, significantly raises the likelihood of nightmares.

Evaluating Nightmares

Evaluating nightmares typically involves structured clinical interviews or self-report measures. Structured clinical interviews are ideal, but they can be time-intensive.¹³ A more efficient tool is the Nightmare Disorder Index, which has been validated against structured interviews and provides a brief screening of key diagnostic criteria.¹⁴

Unfortunately, nightmares are often underreported in sleep labs, as individuals may experience them less frequently in a controlled environment. This discrepancy complicates the diagnostic process.

Treatment Options for Nightmares

Current treatments for nightmare disorder include both psychotherapy and pharmacotherapy. The American Academy of Sleep Medicine’s 2018 Position Paper for the Treatment of Nightmare Disorder in Adults is an excellent resource for clinicians that provides guidance on the use of pharmacologic and nonpharmacologic treatment options.¹⁵

Imagery Rehearsal Therapy

The AASM recommends imagery rehearsal therapy as the primary treatment for nightmare disorder, especially in cases related to PTSD.¹⁵ Imagery rehearsal therapy involves helping patients rewrite their nightmares in a less distressing manner. This therapeutic approach encourages individuals to confront their nightmares in a safe environment, allowing them to rescript the narrative and practice the new version, which can lead to a reduction in nightmare frequency.

Pharmacotherapy

Pharmacological options have also been explored. The Department of Veterans Affairs suggests Prazosin, an antihypertensive drug, for treating PTSD-related nightmares, despite the evidence being somewhat weak.¹⁶ However, a clinical trial involving veterans found that Prazosin did not significantly alleviate distressing dreams or improve sleep quality.¹⁷

CPAP

In a 2019 study that indicated a clear association between PTSD, comorbid obstructive sleep apnea (OSA), and nightmares, the authors found a significant improvement in nightmare frequency with continuous positive airway pressure (CPAP) treatment.¹⁸ Compliance with CPAP therapy correlates with fewer nightmares, suggesting a potential avenue for intervention in patients with OSA experiencing nightmares.¹⁹ (See Figures 1 and 2.)

Future Directions in Nightmare Research

Moving forward, it is essential to differentiate between idiopathic and trauma-related nightmares and to better understand the mechanisms linking waking experiences to nighttime disturbances. More research is needed to establish effective treatment targets and develop integrated approaches for treating comorbid conditions, especially in psychiatric patients.

Moreover, healthcare providers must proactively inquire about nightmares during assessments, as many individuals with significant nightmares may not report them. A multi-dimensional approach to sleep health is vital, encompassing duration, quality, and specific sleep disturbances like nightmares.²⁰

Conclusion

Nightmares are a complex phenomenon that can significantly impact mental health and sleep quality. Understanding their prevalence, associated risk factors, and treatment options is crucial for effective management. As research progresses, we hope to uncover more about the underlying mechanisms of nightmares and improve interventions for those affected.

By Christine So, PhD

Source: SleepWorld Magazine Jan/Feb 2025

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Figure 1. Mean frequency of nightmares before and after CPAP by REM/NREM OSA (with 95% CI).¹⁹ 

Figure 2. CPAP compliance and number of nightmares per week after CPAP therapy.¹⁹