Sleep Apnea and Panic Attacks Matthew J. Edhmd, M. Eileen McNamara, A survey nocturnal diagnosis Copyright
and Richard P. Millman
of 301 sleep apnea patients demonstrated that obstructive sleep apnea may cause panic attack symptoms. Sleep apnea should be considered in the differential of nocturnal panic disorder. 0 1991 by W.B. Saunders Company
LTHOUGH obstructive sleep apnea may cause depression and anxiety symptoms,’ psychiatric clinicians generally do not consider sleep apnea in the differential diagnosis of panic disorder. Although nocturnal panic attacks may occur in up to 69% of patients with panic disorder,” surveys of panic patients’ nocturnal attacks have not considered whether concomitant sleep disorders might contribute to or cause these symptoms.3 To see if panic symptoms might be the result of obstructive sleep apnea, a group of patients with this disorder were surveyed for panic symptoms. METHOD Over a 26-month period from 1986 to 1989,301 patients were diagnosed in a university laboratory by all-night polysomnography as suffering from obstructive sleep apnea. The diagnosis of obstructive sleep apnea was based on the finding of 10 or more obstructive apneas and hyponeas per hour of sleep. Sleep was scored using the method of Rechtschaffen and Kales.’ Apnea was defined as a total absence of airflow for 10 seconds or longer,’ whereas hypopnea was defined as a decrease in airflow lasting at least 10 seconds and resulting in a 4% decrease in oxygen saturation and/or an arousal from sleep. Events were considered obstructive if airflow was absent or decreased despite continued diaphragmatic activity. Each patient received the same structured intake interview from a single pulmonary sleep clinician. First, they were asked if anyone had witnessed them to stop breathing or hold their breath during sleep. They were then asked whether they had ever woken with the sensation they were not breathing. Those patients who recognized they had stopped breathing were asked whether they ever experienced panic on awakening. Eighteen patients admitted having awakened in panic during the night. Of those, 16 were successfully contacted 6 months to 2 years later for a semistructured interview regarding panic symptoms and the effects of treatment. Their characteristics are given in Table 1.
Of the 16 patients contacted, two denied ever having panic symptoms in the middle of the night. Of the rest, four had a period during which time they had a sufficient number of attacks of sufficient severity (four major attacks in 4 weeks) to potentially obtain a DSM-III-R diagnosis of panic disorder (if the organic cause of sleep was not excluded). Seven had full-fledged panic attacks, but of insufficient frequency to merit a diagnosis of panic disorder, and three had symptoms that would merit the diagnosis of a minor panic attack.
From the Departments of Psychiatry and Medicine, Rhode Island Hospital and Brown University. Providence, RI Address reprint requests to Matthew J. Edlund, M.D., Sarasota Palms Hospital, 1650 S Osprey Ave. Sarasota, FL 34239. Copyright Q 1991 by W B. Saunders Company OOIO-440X/91/3202-0011$03.OOlO
Psychiatry, Vol. 32, No. 2 (March/April),
1991: pp 130-132
SLEEP APNEA AND PANIC ATTACKS
Table 1. Characteristics
Anxiety Symptom PD PD FP FP NA PD PD FP MP NA PD MP FP FP MP FP
35 43 50 53 38 45 55 53 44 50 44 46 36 40 43 32
73 67 70 71 69 66 70 71 67 64 69 64 69 66 70 70
of 16 Panic Attack/Sleep
Base 0, Sat (%) 378 230 175 238 282 220 250 260 210 190 180 190 186 280 320 275
95 90 95 95 96 69 95 94 92 97 94 96 95 90 91
Apnea Subjects Nadir During Apnea
70 80 93 80 90 88 81 81 85 93 94 88 87 42 52 60
96 55 10 80 35 35 50 40 38 16 11 85 15 101 90 60
Yes No Yes Yes Yes Yes Yes No Yes
Yes Yes Yes Yes Yes
Abbreviations; PD, panic disorder by DSM-III-R criteria (not excluding organic cause); FP, major panic attacks, but less than four attacks in 4 weeks; MP, minor panic attacks, as defined by DSM-III-R; NA, denying panic symptoms on reinterview; AI-II, Apneas and hypopneas per hour sleep.
Twelve of the 16 reported waking up choking in the middle of the night, and 10 reported symptoms of both shortness of breath and palpitations at night. Other common symptoms were dizziness (5/16), fear of dying (6/16), and fear of doing something crazy or uncontrolled (5/16). Seven reported generalized anxiety during the day. Importantly, when treated with continuous positive airway pressure (CPAP), the panic symptoms diminished or disappeared. This is exemplified by the following cases. Case 6 Mr. N, 45, was anxious most days for the last 6 years. He also had great difficulty sleeping, and was placed on alprazolam for his anxiety. Treatment did not help the anxiety, and his sleep became worse: “I would wake up and think I was having a heart attack.” He would have more than one panic attack per week, usually at night, but sometimes in the day. Treatment with CPAP terminated his panic attacks, both nighttime and daytime.
Case 7 A 55-year-old man reported symptoms of choking and waking in panic in the middle of the night for several months. He also noted that he was increasingly anxious at work, finding that he would When his sleep apnea was treated with sometimes, for no reason, be “screaming in the workplace.” nasal CPAP, his panic attacks stopped, as did his daytime anxiety. His anger in the workplace also considerably diminished.
Case 16 A 32-year-old man reported sleep apnea symptoms for approximately bed” at night, and was “always sleepy” during the day. He was given nighttime panic attacks grew more frequent, from one to approximately anxiety also increased, as did the number of arousals during sleep. His with CPAP treatment, and his panic attacks are gone.
1 year. He would “jump out of diazepam for his anxiety. His three per month. His daytime anxiety is markedly decreased
Nocturnal panic symptoms do occur in patients with sleep apnea. In the group described here, it is noteworthy that all were male (unlike panic disorder presentations in outpatient clinics, where females predominate), most were older than the typical panic patient, and many were obese. In many of these patients, panic symptoms diminished or disappeared with treatment by CPAP. The clinical vignettes were typical of all the patients, and two of the three experienced worsened panic with benzodiazepines, unlike most panic patients. This is because benzodiazepines may potentially make sleep apnea worse. Excluding concomitant sleep apnea should be a concern in all patients treated with benzodiazepines, as these drugs may exacerbate sleep apnea. However, tricyclic antidepressants and monoamine oxidase inhibitors would generally not be expected to worsen sleep apnea. There are several difficulties with a retrospective study of this kind. First, only patients who knew they stopped breathing were asked about panic symptoms. Most patients with sleep apnea are not aware that they stop breathing, and usually learn this from a spouse. Second, only a single screening question was used to elicit panic symptomatology. Third, only patients with documented obstructive sleep apnea were considered. It is possible that sleep apnea patients have panic attack symptoms in excess of the 5% (14/301) found in this study. Both sleep apnea and panic disorder are relatively common in the general population, and it may be expected that some patients will have both disorders. However, all the patients we studied with sleep apnea and panic symptoms reported diminution or disappearance of their panic attacks when their sleep apnea was treated. Sleep apnea may cause nocturnal panic attack symptoms. Although not considered in this study, other sleep disorders, particularly the parasomnias (M. Mahowald, personal communication), may also produce nocturnal panic symptoms. To clarify these issues, groups of panic patients, particularly middleaged men, should be studied for signs and symptoms of sleep apnea and other sleep disorders.6 Sleep apnea and parasomnias should be part of the differential diagnosis of panic disorder, especially when panic attack symptoms are predominantly nocturnal. REFERENCES 1. Millman RP, Fogel BF, McNamara ME, et al: Depression as a manifestation of obstructive sleep apnea: Reversal with nasal continuous positive airway pressure. J Clin Psychiatry 50:348-351, 1989 2. Mellman TA, Uhde TW: Sleep in panic and generalized anxiety disorders, in Ballenger JC (ed): Neurobiological Aspects of Panic Disorder. New York, NY, Liss. 1989 3. Craske MG, Barlow DH: Nocturnal panic. J Nerv Ment Dis 177:160-167,1989 4. Rechtschaffen A, Kales A (eds): A Manual of Standardized Techniques and Scoring System for Sleep Stages of Human Subjects. Los Angeles, CA, Brain Information. Service and Brain Research Institute, 1968 5. Block A, Boysen P, Wynne J, et al: Sleep apnea. hypopnea, and oxygen desaturation in normal subjects. N Engl J Med 300: 513-517. 1979 6. Mellman TA, Uhde TW: Electroencephalographic sleep in panci disorder. Arch Gen Psychiatry 46: 178-184. 1989