Circadian rhythm disorders in manic-depressives

Area of Science:

• Chronobiology
• Psychiatry
• Genetics

Background:

• Manic-depressive illness (bipolar disorder) is a mood disorder characterized by cycles of mania and depression.
• Circadian rhythms, or the body's internal biological clock, regulate various physiological processes.
• Disruptions in circadian rhythms have been implicated in mood disorders.

Purpose of the Study:

• To investigate the relationship between circadian rhythmicity and manic-depressive illness.
• To explore the effect of lithium treatment on circadian rhythms in patients with manic-depressive illness.

Main Methods:

• Studied seven individuals with circular manic-depressive illness throughout their mood cycles.
• Assessed circadian rhythm speed and the impact of lithium on these rhythms.

Main Results:

• Five subjects exhibited evidence of a fast-free-running circadian rhythm.
• Lithium treatment appeared to slow the circadian rhythm in five subjects.
• Two non-responders to lithium had seemingly slow circadian clocks.

Conclusions:

• A fast circadian clock may be a contributing factor to manic-depressive illness.
• Lithium's therapeutic effect might stem from its ability to slow an overactive circadian clock, preventing desynchronization.
• The findings support a circadian etiology for manic-depressive illness, consistent with genetic and age-related patterns.