The nocturnal panic attacks: polysomnographic features and comorbidities

Abstract

Background Panic disorder refers to the repeated or unexpected anxiety or panic attacks. It makes patients feel extreme pain. Although the episodes of most patients with panic disorder happen at daytime, the nocturnal panic attacks (NPA) are quite common. Paients pay more attention to NPA. Insomnia is more serious in patients with NPA than those patients with panic disorder attack at daytime. Many patients may occur anxiety and avoidance behavior after NPA. Patients are often afraid of sleeping, or even do not sleep. The aim of this study is to analyze polysomnographic (PSG) parameter changes and clinical concomitant symptoms of patietns with NPA, to explore the characteristics of sleep, in order to provide better diagnosis, differential diagnosis and treatment for these patients. Methods The features of sleep of 20 NPA patients and 23 healthy controls were monitored by video-PSG. Hamilton Anxiety Rating Scale (HAMA) and Hamilton Depression Rating Scale (HAMD) were used to assess the state of anxiety, depression, and dyssomnia of the patients. Results In comparison with normal control group, the NPA group showed shortened total sleep time (TST), decreased sleep efficiency (SE) and sleep maintenance rate, delayed arousal time, increased number of arousal and number of arousal episode longer than 5 minutes, increased percentage of non-rapid eye movement (NREM) sleep stage Ⅰ, decreased percentage of NREM sleep stageⅢ and percentage of rapid eye movement (REM) sleep (P < 0.05, for all). There was no significant difference in sleep latency (SL) and REM sleep latency (RSL), wake-up time, the number of REM sleep, percentage of NREM sleep stage Ⅱ, apnea index (AI) and apnea hypopnea index (AHI) between two groups (P > 0.05, for all). In NPA group, there were 13 cases (13/20) with anxiety, 17 (17/20) with depression, 13 cases/times (13/20) with difficulty of falling asleep, 17 cases/times (17/20) with difficulties in maintaining sleep (frequent arousals and difficult to fall asleep again) and 7 cases/times (7/20) with wake up early. Conclusion NPA patients present decreased deep sleep, increased shallow sleep and poor sleep quality, and are mostly accompanied with mild or moderate depression and (or) anxiety, and dyssomnia. Application of polysomnography can rule out those diseases (for example, obstructive sleep apnea syndrome, nightmare, etc) which may easily confuse with NPA, and avoid misdiagnosis.