Premenstrual symptomatology: an interaction hypothesis.

An experiment on mood changes in relation to the premenstrual phase of the cycle is reported. Two groups of 24 female phobic patients (one with natural cycles and the other taking the oral contraceptive) were tested either premenstrually or intermenstrually using concurrent and retrospective methods of mood assessment. Although subjects retrospectively reported experiencing negative mood changes during the premenstrual phase as compared to the intermenstrual phase, no such differences were found when subjects were tested at these particular phases when the purpose of the study was disguised. The implication of this finding, together with those reported previously concerning conditionability and defensive reactions, are discussed.