The Diurnal Pattern of Salivary Flow in Normal and Depressed Patients

Attempts to correlate diagnosis or prognosis in depression with metabolic or autonomic parameters have been largely unsuccessful. Although electrolyte fluctuations coincide with some cyclical psychoses (Rey, 1957) these may be causal or incidental and their endocrine origin is undefined. Similar difficulties are inherent in studies of autonomic function (Martin, 1960) which have included observations on skin temperature and resistance (G.S.R.), heart rate, pupil reactions and muscle potentials. Much interest has focused on the blood pressure, and the Funkenstein test has emphasized the difficulties of this research. After widespread study and application, its prognostic value, the reliability of its measurements and the basic theoretical assumptions are now largely discredited (Rose, 1962). In the search for reliable objective criteria to evaluate or explain the phenomena of mental illness salivary secretion may prove of considerable value.