Biomedical subjects
Publications and source records attributed to D F Kripke.
Ninety to 120 min ultradian rhythms have been described in physiologic and behavioral functions relating to biologic drives. Gastric contractility rhythms were examined in isolated fasting volunteers to supplement behavioral observations of "oral" drives. A clear ultradian rhythms was observed, indicating inherent physiologic oscillation in stomach contractions.
Sleep disturbance was studied in relation to psychiatric and physical symptoms for 214 male psychiatric outpatients and 248 male nonpatients. Our self-report instrument required that subjects describe the frequency of symptoms precisely on a five-point scale from "every day" to "not at all." Percentages are based on the numbers of subjects reporting a symptom as occurring "every day" or "several times a week." More patients reported sleep disturbance symptoms (75%) than nonpatients (25%) (P less than 0.001). Sleep loss symptoms were reported by 63% of patients and 20% of nonpatients. Twelve percent of patients and 6% of nonpatients reported trouble with excessive sleep problems. Sleep disturbance was not strongly related to specific diagnoses. Fewer schizophrenics (21%) than other patients (50%) reported trouble "falling asleep" (P less than 0.02). Finally, for both patients and controls, disturbed sleepers reported more psychiatric and physical symptoms than undisturbed sleepers (P less than 0.001). It is suggested that sleep disturbance might be a useful clinical clue to previously unsuspected psychiatric and physical illness.
Several reports have suggested that heart rate may be regulated by an ultradian biological rhythm with a period of about 90--100 min. Blood pressure and heart rate were collected from 10 Surgical Intensive Care patients at 5-min intervals and analyzed by computer. No 90-min rhthms were found, indicating this rhythm has no significant influence on heart rate or blood pressure in postsurgical patients.
Three manic-depressives were studied longitudinally. Several times a day, the patients measured and recorded their mood, vigor, oral temperature, finger counting, blood pressure, pulse rate, and urine volume. Then the acrophases of their circadian rhythms were computed by a least-squares fit. These patients displayed rhythm phases that were grossly abnormal. Systematic acrophase changes over time supported the hypothesis that manic-depressives have circadian rhythms that free-run faster than one cycle per 24 hrs. Lithium appeared to slow these rhythms and help the environmental synchronizer force physiological functions to coordinate better with the usual 24-h environmental cycles.
There is little rigorous evidence that shiftwork produces specific psychiatric disturbances. Substantial evidence suggests that shiftworkers are prone to increased drug and alcohol consumption, but the frequency with which this leads to actual drug abuse disorders has never been adequately defined. A preponderance of studies suggests that symptoms of a "neurotic" character are overrepresented among nightshift workers. The nature of these symptoms needs to be clarified with modern psychiatric nomenclature. It seems likely, based on certain experimental work, that nightshift work may at times exacerbate mood disorders, leading to an impression of "neurotic" disturbance. At the same time, some conditions of shiftwork might actually palliate mood disorders. Therefore, a reexamination of these issues is needed with improved research designs and more careful characterization of the nature of workers' complaints, their psychiatric histories (i.e., personal and family histories of mood disorders and other psychopathology), and possible specific effects of particular shiftwork rotation schedules. Use of bright light to alleviate mood disturbances associated with shiftwork needs extensive empirical testing.
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