Letters to the Editor
Pregnancy and Respiratory Nocturnal Panic Attacks
Pregnancy may have a highly variable influence on the course of panic disorder (PD) (1). Some case reports suggest that pregnancy protects against PD (2), but worsening or no change of PD during pregnancy is also reported (1).
We describe 2 women who were referred to the Laboratory of Panic and Respiration of the Federal University of Rio de Janeiro, with PD with prominent respiratory nocturnal panic attacks during pregnancy only.
Case Report 1
Mrs A, a 30-year-old white woman, started at age 26 years to have spontaneous diurnal attacks with palpitations, shortness of breath, choking, chest pain, dizziness, and fear of losing control. She was treated with imipramine (150 mg daily). After 18 months, she was asymptomatic and started to decrease the dosage. She had her first pregnancy after being free of psychotropic medications for 1 year. During the fourth month of pregnancy, however, she developed recurrent panic attacks during sleep. Her nocturnal panic attacks were intense and occurred almost nightly, with prominent respiratory symptoms (shortness of breath, chest pain, tingling, fear of dying and losing control, and severe choking). She never experienced nocturnal panic attacks before her pregnancy. She developed agoraphobic behaviour; she could only sleep seated, given her intense anticipatory anxiety at nightfall. She was initially treated with nortriptyline 10 mg daily. After 6 weeks, at the dosage of 75 mg daily, she achieved full remission of her respiratory nocturnal panic attacks. During her pregnancy, there was no diurnal panic attack. During the last 2 weeks of her pregnancy, nortriptyline was no longer prescribed. The asymptomatic period persisted after a 2-year follow-up.
Case Report 2
Mrs B, a 32-year-old white woman, began having diurnal panic attacks at age 22 years. During her panic attacks, the main symptoms were choking and shortness of breath. She was treated with paroxetine 20 mg daily. After 2 months, she no longer had panic attacks. For the next 32 months, she remained asymptomatic. During the fifth month of her second pregnancy, however, she started experiencing nocturnal panic attacks, with shortness of breath, chest pain, dyspnea, choking, paresthesias, sweating, tachycardia, and severe fear of dying. There was an intense anticipatory anxiety during sleep. She developed fear in falling asleep and performed her usual daily activities during the night. She was treated with nortriptyline and a dosage of 75 mg daily achieved complete remission. The drug was gradually discontinued during the last month of her pregnancy. At her 3-year follow-up, she had been without any panic attacks.
The respiratory PD subtype appears as a distinct sample (3). Nocturnal panic attacks are common, often neglected, and have been presenting with important respiratory symptoms. The physiology of the sleep, characterized by a significant rise of blood CO2 (4), may explain why nighttime is favourable for developing panic attacks in patients with PD, a population characterized by heightened CO2 sensitivity (4). Sex hormones influence respiration, and pregnancy is characterized by a strong physiologic fluctuation of their blood levels. The rise of progesterone levels may protect against panic attacks by facilitating GABA-ergic activity and by diminishing arterial CO2 levels through increased minute ventilation (5); however, synthetic progesterones can cause severe dyspnea, tachypnea, and hyperventilation (6), and estrogens can induce panic attacks (7). We can conclude that, during pregnancy in some patients with PD, the balance among sex hormones may negatively effect respiratory sensitivity, thus inducing panic attacks. In addition, during nighttime, the pregnant woman’s sleeping position may obstruct diaphragmatic breathing, modifying respiratory patterns to the extent that they enhance the possibility of nocturnal panic attacks.
1. Villeponteaux VA, Lydiard RB, Laraia MT, Stuart GW, Ballenger JC. The effects of pregnancy on preexisting panic disorder. J Clin Psychiatry 1992;53:201–3.
2. George DT, Ladenheim JA, Nutt DJ. Effect of pregnancy on panic attacks. Am J Psychiatry 1987;144:1078–9.
3. Briggs AC, Stretch DD, Brandon S. Subtyping of panic disorder by symptom profile. Br J Psychiatry 1993;163:201–9.
4. Klein DF. False suffocation alarms, spontaneous panics, and related conditions: an integrative hypothesis. Arch Gen Psychiatry 1993;50:306–17.
5. Biggio G. CO2 Inhalation enhances the brain content of neurosteroids and reduces GABAa receptor function. In: Bellodi L, Perna G, editors. The panic respiration connection. Milan: MDM Medical Media Srl; 1998. p 111–25.
6. Fujii K, Kohrogi H, Hirosako S, Kawano O, Hirata N, Goto E, and others. Dyspnoea and hyperventilation induced by synthetic progesterone chlorpromadinone acetate for the treatment of prostatic hypertrophy. Respirology 2001;6:265–7.
7. Griez E, Hauzer R, Meijer J. Pregnancy and estrogen-induced panic. Am J Psychiatry 1995;152:1688.
Antonio E Nardi, MD
Fabiana L Lopes, MD
Alexandre M Valença, MD
Isabella Nascimento, MD
Rio de Janeiro, Brazil
Giampaolo Perna, MD