Circadian fluctuations in anxiety disorders.

To the Editor: Predictable rhythmic fluctuations, especially circadian, have been observed in a wide variety of physiologicai and psychological functions. Abno~a~ities of circadian patterns have been documented in people with depression, including a tendency for maximal severity of depression in the morning; however, patients with anxiety or mixed depression/anxiety report a tendency for symptoms to be worse later in the day (Kiloh and C&side 1963; Mendefs and Cochrane 1%8; Roth et al. 1972; Mathew et al. 1982; Mullaney 1984; Faravelli et al. 1985; Von Zerssen et al. 1985). Despite this observation, no systematic study of potential circadian fluctuations of anxiety in people with clinical anxiety disorders has appeared; that is the purpose of this investigation. Thirty patients (20 with DSM-lli-defined panic attacks and 10 with other anxiety disorders; 23 women; mean age 36 years) at the time of diagnostic evaluation retrospectively rated their average anxiety level at five different times of day (early morning, late morning,, mjdaftemoon, early evening, and late evening) on a 6point scale (none, very mild, mild, moderate, severe, and very severe) for a good day, an average day, and a bad day for the previous several months. Nineteen of these women who had active menstrual cycles also rated their anxiety on a 5-point scale (worse, somewhat worse, unchanged, somewhat better, and better) at four times during the menstrual cycle (premenstrual week, during menses, postmenstrual week, and midcycle). Finally, all patients who reported panic attacks rated the frequency of attacks that woke them from sleep. A statistically significant fluctuation in severity of anxiety throughout the day was observed (repeated measures Analysis of Variance: F = 3.30, p < 0.05); when only patients with panic attacks were included, the severity level and pattern through the day were very similar. The lowest level was at late morning and the highest early evening, with a fluctuation of approximately one-half of a rating gradation over the five time points (e.g., mild to midway between mild and moderate for an average day). There was also a statistically significant fluctuation over the menstrual cycle, with peak severity (somewhat worse) in the premenst~a1 week (repeated measures Analysis of Variance: F = 6.70, p < 0.01). Forty-five percent of the patients with panic attacks reported that attacks sometimes awoke them from sleep; for these patients, approximately 11% of the attacks occurred during sleep. These results demons~ate that, unlike melancholic depression, people with anxiety disorders, par titularly panic attacks, tend to experience increased symtoms later in the day. Although the fluctuation through the day was not great, these results are in agreement with the prior unsystematic studies listed above. Menstrually related fluctuations of anxiety severity were also observed. Prior studies of menstrually related fluctuations of anxiety in normal women have produced mixed results (Golub 1976; Alplanalp et al. 1977; Lahmeyer et al. 1982; Veith et al. 1984; Van Den Akker and Steptoe 1985). Although it has been claimed that panic attacks are more likely to occur premenstrually (Rubinow and Roy-Byrne 1984), this is the first published documentation. Further study will be necessary to elucidate the mechanisms of the observed fluctuations.