This study will provide preliminary estimates of safety and efficacy of the NightWare digital therapeutic system (iPhone + Apple watch + proprietary application) for the treatment of nightmare disorder associated with post-traumatic stress disorder (PTSD)-related sleep disturbance and the impact of improved sleep with the NightWare digital therapeutic system. The investigators hypothesize that the NightWare digital therapeutic system will significantly improve sleep quality in participants with PTSD-Related nightmares and poor sleep quality.

Nightmares are a common problem affecting 2-8% of the general population and a higher proportion of clinical populations. The negative consequences of untreated nightmares are significant and include impaired quality of life, sleep deprivation (often resulting in an increased intensity of nightmares), insomnia, daytime sleepiness, and fatigue. Untreated nightmares can also exacerbate the symptoms of underlying psychological dysfunction in people with depression and anxiety, leading to poor occupational and or social functioning. Nightmares can be idiopathic or associated with the use (or withdrawal) of certain medications or substances, or associated with disorders including PTSD.

NightWare (Minneapolis, MN) has developed a novel approach to the treatment of nightmares. Through the use of a smartwatch-based application that senses physiologic parameters, the participant is aroused from sleep (without awakening the participant) so that the nightmare is interrupted prior to reaching a threshold of severity in which the participant would awaken in distress. Seconds later the participant returns to sleep without having experienced a nightmare. This approach avoids risk from pharmacological treatment, avoids exacerbation of symptoms from image rehearsal therapy and allows for a simple method with easily achieved adherence compared to existing treatments.

The NightWare digital therapeutic system consists of a proprietary software application installed on a smartwatch. The application has been effective in focus groups when used on both Apple smartwatches and Motorola smartwatches. For the purposes of this study, the investigators will be using only the Apple (Cupertino, CA) 3rd generation smartwatch and the Apple iPhone. The NightWare application uses physiological markers obtained via the smartwatch to determine by proprietary algorithm whether a participant is in the early stages of a nightmare, but has not yet awoken in distress. As directed by the algorithm, the smartwatch then applies varying degrees of vibratory stimulation to the wrist over variable lengths of time with the intention of arousing the participant from sleep without eliciting an awakening.

Inclusion Criteria:

• Veterans and Active-Duty Service Member Enrolled in the Minneapolis/St. Cloud VAHCS, Louis Stokes VAHCS in Cleveland, Walter Reed National Military Medical Center, or Fort Belvoir Community Hospital
• Diagnosis of PTSD via American Psychiatric Association PTSD diagnostic criteria in the fifth edition of its Diagnostic and Statistical Manual of Mental Disorders (DSM-5).
• Equal to or older than 22 years of age.
• Proficient in both reading and writing in the English language.
• Pittsburgh Sleep Quality Index (PSQI) score 10 or higher.
• Epworth Sleepiness Scale (ESS): On question #8 any score above "0" will prompt an additional question: Do you drive ("get behind the wheel") when you are drowsy? The answer must be "No" to be enrolled in the study due to safety concerns.
• Have repetitive nightmares contributing to disrupted sleep as reported by the patient
• Wireless Internet and two power outlets where they sleep
• Prazosin use; if yes, the patient may be included if tapered by prescribing provider. Taper must be completed and subject must be off prazosin for 2 days prior to enrollment.

Exclusion Criteria:

• Patient Health Questionnaire-9 (PHQ-9) score greater than or equal to 20. A score of 1 or more on the suicide ideation item of the PHQ-9 will trigger a risk assessment.
• Uncontrolled atrial fibrillation
• Current use of varenicline
• Current use of beta-blockers (unless ophthalmic solutions)
• Current use of non-dihydropyridines
• Current use of Prazosin for the treatment of nightmares (can include patients 2 days following taper and discontinuation) This would be coordinated with the prescribing provider
• Circadian rhythm disruption on a regular basis (shift-work)
• Untreated Obstructive Sleep Apnea
• Diagnosis of an active disorder of arousal from non-rapid eye movement sleep
• Diagnosis of rapid eye movement sleep behavior disorder
• Diagnosis of narcolepsy
• Alcohol Use Disorders Inventory Test (AUDIT) (score of 8 or higher)
• Drug Abuse Screening Test-10 (DAST-10) (score greater than 2)
• Suspicion of nightmares being secondary to substance abuse or withdrawal
• Diagnosis or suspicion of dementia
• Previous or foreseeable legal proceedings involving nightmares or trauma
• Nocturia that causes awakening from sleep
• Known sleepwalking
• Acting out of dreams prior to PTSD trauma