Some biological factors which have been shown to be abnormal in subgroups of women with dysphoric premenstrual syndromes (PMS) have not been limited to the symptomatic late luteal phase of the menstrual cycle, but also existed during the non-symptomatic mid-follicular phase of the cycle. Personality, cognitive functions, α2 and imidazoline binding, sensitivity to inducement of panic attacks, relative hypothyroidism, and some but not all serotonergic functions of women with dysphoric PMS differ from those with no PMS, and also differ during a non-symptomatic phase of the cycle. It is suggested that premenstrual symptoms are an expression of vulnerability traits that might surface in response to a trigger. Such traits are probably diverse, and the nature of the symptoms might depend upon the underlying trait. It is postulated that some vulnerability traits to specific premenstrual syndromes might also be vulnerability traits to depression or anxiety in general.