Periodic phenomena and the thyroid. I. Abnormal but regular cycles in behavior and metabolism produced in rats by partial radiothyroidectomy.

Under normal conditions men and women do not show any readily detectable periodicity in behavior, mood, or metabolism, except, of course, for the 24-hour cycle of sleep and waking and the 28-day menstrual cycle of females; however, under certain kinds of illness, in some instances mental, in others physical, men and women show regularly recurring phenomena that may affect both mind and body. Records are at hand of many mentally ill persons who have the most regular attacks during which they may undergo marked pathological changes in personality, thinking, and attitude toward life in general, while in the intervals between the attacks they are entirely normal. During the attacks any one person may show one or more of the following symptoms: sadness, elation, stupor, uncontrollable suspiciousness, fear, lethargy, and aggressiveness; this person may also show one or more of the following physical symptoms: fever, elevated pulse rate, increased blood pressure, headache, and pain in joints, muscles, or internal