Affective Disorders and Circadian Rhythms

Abstract

Abnormal circadian rhythms have been associated with affective disorders. A review of this rapidly expanding area of investigation shows that while a clear causal relationship has not yet been proven, a knowledge of the circadian system and its dysfunction can help in understanding unipolar and bipolar depression. Evidence suggests that existing therapies such as lithium and antidepressants act upon the circadian system. Better identification of individuals at risk for affective disorders and the development of new preventive and therapeutic interventions may result from further study of circadian dysfunction.

Effects of Antidepressants on 5-HT7 Receptor Regulation in the Rat Hypothalamus

“…Just as important, these results provide further evidence to support the theory that one of the consequent mechanisms of antidepressant treatment is a modulation of possibly dysrhythmic circadian function in depression (Duncan 1996;Healy 1987;Hallonquist et al 1986). Clinically, the therapeutic relevance of circadian modulatory activity by antidepressants enhances our knowledge of the interactive, and perhaps, interdependent nature of circadian function and affective disorders.…”

“…The strict classical notions of neurotransmitter dysregulation hypotheses that associate depression with a deficiency of a vailable neurotransmitter or subresponsivity of mainly noradrenergic and/ or serotonergic receptor systems are recently being expanded to include disturbances in biological rhythm regulation. Impairment of the efficiency of rhythm maintenance or rhythm desynchronization has been suggested by many to lead to mental fatigue and depression (Goodwin et al 1982;Hallonquist et al 1986;Healy 1987;Partonen 1994;Schwartz 1993;Wirz-Justice and Campbell 1982;Wirz-Justice et al 1995). Clinically, it has been extensively documented that the timing and structure of rhythms in physiological, behavioral, and endocrinological functions seem to be abnormal in depression (Coiro et al 1993;Duncan 1996;File 1990;Kupfer 1995;Nair and Sharma 1989;Wehr et al 1979).…”

Effects of chronic administration and withdrawal of antidepressant agents on circadian activity rhythms in rats

“…Food intake was measured every week and body weight every 2 weeks during the regular checks of animals. Statistical parameters of the wheel-running rhythms were computed for each of the following three conditions: baseline (days 1-14), drug treatment (days [15][16][17][18][19][20][21][22][23][24][25][26][27][28], and drug withdrawal (days 29-42).…”

“…Repeated-measures ANOV A indicated significant differences between body weights of the three strains, with animals of the ACI strain being generally lighter than animals of the BH and LEW strains. In all six experiments, drug treatment (days [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] caused a temporary halt in the otherwise continuous increase in body weight, and sometimes even a decrease, for example, in the ACI strain under Ro 19-6327, desipramine, and clomipramine treatment. However, these effects were minor and did not affect the health or well-being of animals.…”

“…For example, studies in humans have shown that affective disorders are associated with abnormalities in the period, phase, and/or amplitude of physiological, behavioral, and endocrine rhythms, resulting in quite a number of different hypotheses on the chronobiology of depression (16,18,20,39,41). Special attention has been paid to the observation that many circadian rhythms, including the circadian rhythm of rapid eye movement (REM) sleep and deep body temperature, are phase advanced in depressed patients compared to controls (12,27 ,42,43).…”