Doldrums is defined as a gloomy feeling, low spirits or a time of inactivity. An example of doldrums is being stuck in the house during a week long snow storm. doldrums
Conversion disorder is a type of somatoform disorder where physical symptoms or signs are present that cannot be explained by a medical condition. Very importantly, unlike factitious disorders and malingering, the symptoms of somatoform disorders are not intentional or under conscious control of the patient.
There are also other secondary or peripheral biological clocks throughout the body, such as in the liver, heart, pancreas, kidneys, lungs, intestines, and even in the skin and lymphocytes, all of which show natural daily oscillations.