Schildkraut J J, Keeler B A, Papousek M, Hartmann E
Science. 1973 Aug 24;181(4101):762-4. doi: 10.1126/science.181.4101.762.
The urinary excretion of 3-methoxy-4-hydroxyphenylglycol (MHPG) was significantly lower in patients with manic-depressive depressions than in patients with chronic characterological depressions. There was an inverse relationship between MHPG excretion and the amount of time spent in desynchronized sleep, particularly in the manic-depressive disorders. Excretion of MHPG was not related to the degree of retardation, agitation, or anxiety in these patients.