Autonomic nervous system studies have engaged the attention of psychiatric research workers since the early publications of Eppinger and Hess.1 However, conflicting results and interpretations reveal the doubt and uncertainty that still lie in this field. Differences of technique and samples are frequently overlooked or minimized and undoubtedly account for much of the existing controversy.
The work to be described was an effort to study the reliability of various methods of performing the epinephrine-methacholine (Mecholyl) test described by Funkenstein and his co-workers.2
We commenced first with a series of test-retest comparisons of the responses to the two drugs separately under slightly differing conditions. The comparisons were made in terms of 11 variables—3 involving basal levels of blood pressure; 2, the extent and duration of response to epinephrine, and 6, the description of the methacholine-response curve. Systolic pressures were used at all times.
After the evaluation of the individual