Jean R. Joseph-Vanderpool

Effects of light treatment on core body temperature in seasonal affective disorder

Abnormalities in circadian rhythms of core body temperature have been reported previously in depressed patients. In this study, we compared the temperature rhythms of 10 depressed seasonal affective disorder (SAD) patients with winter depression with those of 12 normal controls and evaluated the effects of bright light on temperature in SAD. Unlike previous studies of depressed patients, the temperature curves of the patients and normal controls during the off-light condition were nearly identical. We found a significant difference in amplitude between the patients in the untreated and light-treated conditions. Although there was no systematic difference in circadian phase across groups or treatment conditions, we present preliminary evidence that suggests that phase-typed subgroups may be present in the population distinguished by their treatment responses.

The effects of phototherapy in the general population

Patients with recurrent winter depression and its subsyndromal form have been reported to benefit from bright full-spectrum light (phototherapy). In order to determine whether this treatment (2 h in the morning) during winter is effective in a random sample of the general population we investigated the responses of 20 subjects with varying degrees of winter difficulties. A control group (n = 20) matched for the degree of seasonality, age, and sex was treated with dim light. Individuals were selected from a larger survey sample of the Montgomery County population (MD, U.S.A.) and were comparable to the latter in their degree of winter difficulties. Enhancement of environmental light does not, on the basis of the present study, appear to be indicated for the public at large, but rather for a subgroup of individuals with histories of winter difficulties.

Sleep in fall/winter seasonal affective disorder: effects of light and changing seasons.

Disturbances of sleep are a hallmark of seasonal affective disorders (SAD), as they are of other mood disorders. Fall/winter SAD patients most often report hypersomnia. Among responses of 293 SAD patients on a symptom questionnaire, complaints of winter hypersomnia (80%) greatly exceeded insomnia (10%), hypersomnia plus insomnia (5%), or no sleep difficulty (5%). Increased sleep length in fall/winter is not unique to SAD. Among 1571 individuals across four latitudes surveyed at random from the general population, winter sleep increases of < or = 2 hr/day relative to summer were reported by nearly half. However, hypersomnia had a low correlation (r = 0.29) with the total number of other SAD symptoms that were reported in this sample. Ten SAD patients kept daily sleep logs across 1 yr that showed increases in fall and winter (sleeping most in October; least in May) whose maximum averaged 2.7 hr per day more weekend sleep than in spring and summer. These winter increases might have been somewhat attenuated since most received light therapy during part of the winter. Nocturnal EEG recordings of depressed SAD patients in winter showed decreased sleep efficiency, decreased delta sleep percentage, and increased REM density (but normal REM latency) in comparison with recordings: (1) from themselves in summer; (2) from themselves after > or = 9 days of light therapy; or (3) from age- and gender-matched healthy controls. Thus, the extent of fall/winter oversleeping recorded by our SAD patients did not differ dramatically from that reported by the general population, but sleep complaints of our SAD patients have been accompanied by features of sleep architecture that are different from healthy controls and are reversed by summer or by bright-light therapy.

Hormonal responses to the administration of m-chlorophenylpiperazine in patients with seasonal affective disorder and controls

We report on the plasma cortisol and prolactin responses to the serotonergic agonist m-CPP (0.1 mg/kg) in 10 patients with winter seasonal affective disorder (SAD) and 10 controls during the winter, in both untreated and bright light-treated conditions; and on 8 other SAD patients and 8 other controls during the summer. Following m-CPP infusion, untreated patients had exaggerated prolactin (p < .05) and cortisol (p < .05) responses compared to controls. Light treatment significantly reduced responses of both hormones to m-CPP (prolactin: p < .01; cortisol: p < .01). When untreated winter subjects and summer subjects were compared, cortisol, but not prolactin responses to m-CPP were found to be higher in patients than in controls during the winter, and lower in patients than in controls during the summer (diagnosis by season: p < .05). These results are consistent with those of our previous report on the behavioral responses to m-CPP in the same patients and suggest an abnormality in serotonergic function in untreated SAD patients in winter, which is normalized following treatment with light therapy and naturally during the summer.

Core body temperature in patients with seasonal affective disorder and normal controls in summer and winter

The rationale for phototherapy in seasonal affective disorder (SAD) was originally based on the notion that SAD patients were light deprived during the wintertime and needed more light. We previously found normal temperature profiles of untreated SAD patients during the winter, and that phototherapy significantly enhanced the amplitude of the circadian temperature profile in SAD patients during the winter (Rosenthal et al 1990). We hypothesized that summer would act similarly on the temperature rhythm of these patients. In this study we examined the temperature data from SAD patients and normal controls during the summer and compared it to the results of our previous study. We found identical profiles for SAD patients and normal controls during the summer and that summer significantly lowered the overall temperature profiles of both groups and did not alter the amplitudes. These results raise questions about the validity of the current theories of the mechanism of light therapy.

Adaptation to dim light in depressed patients with seasonal affective disorder

Supersensitivity to light has been suggested as a possible trait marker for manic-depressive illness. Because winter seasonal affective disorder (SAD) is associated with depressive episodes during dark winter days, the authors postulated that SAD patients would show diminished sensitivity to dim light. Dark-adaptation curves were obtained in 10 medication-free, depressed SAD patients and in 10 age- and sex-matched drug-free healthy controls. Contrary to the hypothesis, patients adapted to dim light more rapidly than controls.