Table 2.
A summary of studies that assessed dream contents and nightmares in patients with sleep-disordered breathing.
| References | Study sample and protocol | Dreams assessment tools | OSA/Snoring diagnosis measures | Conclusions |
|---|---|---|---|---|
| Gorss and Lavie (25) | 33 patients with OSA slept during two nights in the sleep laboratory. 16 were treated with CPAP) during the first night and 17 during the second. Patients were awakened for dream reports 10 min after the beginning of every REM period. | Patients were asked upon awakening: “what was going through your mind before I woke you up?" Patients were also asked “how they felt in the dream” Dream reports were tape recorded. | PSG | Dreams after obstructive events were significantly more negative than dreams after healthy sleep. The results show no manifest stimulus incorporation in REM sleep dream reports |
| Di Pauli et al. (32) | 63 patients with OSA (mild n = 50%, moderate, 21%, and severe 30%), and 13 subjects as a control group with primary snoring. Patients with OSA were older | Dream reports, and dream questionnaires were collected immediately after first morning awakening | PSG | No significant difference in respiratory-related dream topics between patients and controls The word count of dream reports did not differ between cases and controls. Breathing-related content was not increased in those with higher oxygen desaturation |
| Fisher et al. (17) | A prospective observational study of 47 patients with sleepiness and snoring. Participants were grouped into: sleepy snorers, AHI <5: n = 12; AHI 5–14.9, n = 14; AHI ≥ 15, n = 21 | A morning diary concerning pleasantness/unpleasantness of their dreams for 10 days | A limited-channel home sleep study | All groups reported similar numbers of dreams and nightmares during the diary period. The AHI ≥ 15 group were significantly higher on dream unpleasantness than were the AHI <5 group. The variation in mean dream emotion decreased with increasing AHI |
| Schredl et al. (14) | 444 patients with OSA and 941 healthy controls. Twelve patients had an additional diagnosis of a mental disorder | Nightmare frequency was measured by an eight-point rating scale administered before the first laboratory night | PSG | In general, the respiratory parameters as measures of sleep apnea syndrome severity did not correlate substantially with nightmare frequency Comorbid psychiatric disorders and an intake of psychotropic drugs were associated with heightened nightmare frequency |
| Carrasco et al. (15) | 20 consecutive patients with severe OSA and 17 healthy controls. PSG were recorded at baseline and during the CPAP titration night, 3 months after effective treatment and 2 years later in patients | Subjects were awakened 5–10 min after the beginning of the first and last REM sleep periods and the investigators measured percentage of emotional content of the dream, word count, thematic units, sleep architecture, and REM density | PSG | Violent/highly anxious dreams were only seen in patients at baseline. Dreams in patients with severe OSA had an increased emotional tone and were longer. Violent/highly anxious dreams disappeared with treatment |
| Lovin et al. (26) | 38 patients with OSA had a diagnostic study followed by a therapeutic study within 1–3 weeks | Dream recall was done immediately following spontaneous awakening from REM sleep, and was analyzed for dream content (word count, number of thematic units, and emotional content) | PSG | Dream content was less unpleasant under CPAP |
| Schredl and Schmitt (27) | 1,467 patients with OSA. The control group consisted of 2,929 persons completing an online version of the questionnaire | The Mannheim Dream Questionnaire. For nightmares, the ICSD-3 definition was used. Nightmare distress was measured using a five-point scale | PSG | After controlling for age, gender, and dream recall frequency, patients reported less intense dreams, a less positive attitude toward dreams, and lower lucid dream frequency. Women tended to report more intense Dreams and more positive emotional tone |
| BaHammam et al. (40) | A prospective case-control study of 99 patients with OSA with nightmares and 124 patients with OSA without nightmares. Excluded patients with psychiatric disorders and those on medications that can cause nightmares. | Nightmares were diagnosed according ICSD 2005 | PSG | REM-AHI and interrupted sleep at night were independent predictors of nightmares in the OSA patients. Nightmares disappeared in 91% of the patients who used CPAP compared with 36% of patients who refused to use CPAP |
| Pagel and Kwiatkowski (28) | 394 with severe OSA | A questionnaire with questions on dream and nightmare recall frequency | PSG | Patients with higher AHI report a lower nightmare frequency. However, the study did not report the details of respiratory events during REM sleep in OSA patients with nightmares |
| Hicks and Bautista (41) | 199 university undergraduates completed a questionnaire that assessed their level of snoring and the frequency of nightmares. | Questionnaire | Questionnaire | No significant relationship between snoring and disturbing dreams |
| Schredl (42) | The study assessed the correlations between snoring, and breathing cessation during sleep, and nightmare frequency in a sample of 444 healthy adults | Questionnaire | Questionnaire | Breathing pauses, but not snoring were associated with heightened nightmare frequency |