In all cells, the expression of many genes changes rhythmically over 24 hours. Specific circadian genes such as CLOCK, BMAL1, and PER are responsible for the main SCN clockworking machinery as well as subsidiary clocks in other parts of the body. In mice with mutations in time-keeping genes, deviant circadian sleep-wake and other rhythms can be observed. In addition, new interest in the role of circadian dysregulation in psychiatric disorders has arisen from the finding that a mutation in a core circadian clock gene induces hyperactivity, decreased sleep, and mania-like behaviour in mice (Turek, 2008).
Animal studies were the key development that brought the field to its present exciting position, because their findings suggested that clock genes are directing the circadian rhythms in all physiological processes.
Circadian disturbances: clinical impact on affective disorders
In healthy individuals, physiological and biochemical variables such as body temperature, cortisol and melatonin, thyroid stimulating hormone (TSH), noradrenaline and serotonin exhibit a circadian rhythm. However, in patients with affective disorders, many of these circadian rhythms are disturbed in phase and amplitude (Schulz & Steimer, 2009; McClung, 2007).
For instance, women with depression have a greater degree of variability in the timing of physiological and end
|Contact: Sonja Mak|
European College of Neuropsychopharmacology