The fasting blood acetyl methyl carbinol (A.M.C.) level was shown to be high at the start of the depressive phase in manic-depressives by Dawson, Hullen and Crockett (1). Such cases also showed large fluctuations of fasting blood A.M.C. level compared with normals. The findings in a manic-depressive patient investigated more recently are shown in Figure 1; those in a normal female are given also for comparison. In the manic-depressive, it can be seen that the fasting blood A.M.C. level tended to fluctuate widely, to be high before and at the start of a depressive phase. There is no evidence to suggest that A.M.C. in the quantities found could cause psychiatric manifestations (Stotz, Westerfeld and Berg, 8). It is hence possible that the alterations in A.M.C. level were merely an indication of an abnormal variability of some part of the biochemical milieu. It was decided therefore to investigate patients with other forms of depressive illness to see whether or not abnormalities of A.M.C. level and variability were present, similar to those in manic-depressives.
