3-Methoxy-4-hydroxyphenylglycol and primary depression: clinical and pharmacological considerations

Pretherapeutic urinary excretion of 3-methoxy-4-hydroxyphenylglycol (MHPG) was studied in 25 primary depressed patients. The results indicate that: (i) There exists a wide variability among primary depressives with respect to MHPG excretion. (ii) Age of onset together with polarity of the disease may account for the nonhomogeneous division of the patients according to MHPG levels. (iii). The other variables considered, with the possible exception of motor activity, do not explain the dichotomy between high or normal and low MHPG levels, even though it is possible that they influence MHPG excretion to some extent, with the consequent possibility of errors in subclassification of the patients at the boundaries between the two groups. (iv) The correlation between motor retardation and low MHPG excretion is positive, but probably due to a frequent association between this motricity state and primary depression of bipolar early onset type. (v) Treatments with chlorimipramine and, to a lesser degree of specificity, with amitriptyline are particularly indicated in patients with normal or high MHPG. Some practical and theoretical implications deriving from these data are briefly discussed.