Nocturnal sleep panic and depression: relationship to subjective sleep in panic disorder

Patients with panic disorder (PD) often complain of sleep disturbances. PD patients have high co-morbid depression and almost 65-70% reports a history of nocturnal panic attacks. It is possible that both nocturnal-sleep panic attacks and depression contribute to sleep disturbances in PD patients. However, the individual and interactive effects of nocturnal-sleep panic attacks and lifetime depression on subjective sleep in PD are unknown.

The National Institute of Mental Health Panic Disorder Questionnaire (NIMH-PQ) was administered to 773 individuals who met DSM-IV criteria for PD. All of these subjects completed queries related to nocturnal-sleep panic attacks, lifetime depression, difficulty sleeping, and sleep duration.

We examined difficulty in sleeping and sleep duration in four subgroups [PD without nocturnal panic attacks or lifetime depression (NP-D-), PD with nocturnal panic attacks (NP+D-), PD with lifetime depression (NP-D+), and PD with both nocturnal panic attacks and lifetime depression (NP+D+)]. Significantly greater proportions of NP+D+ subjects reported difficulty sleeping compared to other three subgroups. In addition, the NP+D+ patients reported significantly decreased subjective sleep durations compared to the other three subgroups. Using < or = 5h as a criteria for severe sleep restriction, approximately 20% of the NP+D+ patients, compared to 9.2%, 9.6%, and 2.5% in the NP+D-, NP-D+, NP-D- subgroups, respectively, reported sleeping 5h or less. 8.2% of panic disorder patients reported excessive sleeping per sleeping period.

A high percentage of panic disorder individuals report subjective sleep disturbances. Not surprisingly, an unusually high prevalence of patients with nocturnal panic attacks or depression have sleep problems and 92.3% of patients with both nocturnal panic attacks and depression report striking extremes in sleep duration or insomnia. Thus, nocturnal-sleep panic attacks and depression are independently as well as interactively associated with increased sleep disturbances in panic disorder. Although these findings are expected, they underscore the importance of assessing sleep functions, including over-sleeping, in panic disorder patients.