Nervous disturbances during menstruation, which are so frequent that Emmet regards it as abnormal for a menstruating woman to be entirely free from pain and from uneasy sensations, are divided by Windscheid into two classes, general nervous disorders, and local nervous manifestations. Among general disorders, the commonest is a general bodily incapacity; in women, who in other respects are quite healthy, during menstruation everything will be too great an exertion, and fatigue speedily ensues on the performance of occupations which at other times are undertaken without the slightest difficulty. Another common nervous disorder is an uneasy sensation in the head, it may be a feeling of weight or pressure, sometimes described as a feeling as if an iron band were compressing the forehead. Slight mental irritation is commonly present also, the woman is capricious, her mental equilibrium is disturbed. Very common also are vasomotor disturbances, transient feelings of heat, a sense of congestion in the head, or an outbreak of perspiration. Among local nervous disturbances, Windscheid enumerates, pains in the back (occasionally and erroneously described as spinal irritation), sacrache, pains in the lower extremities, which by preference generally take the course of the great sciatic nerves. Pains in the abdomen also frequently accompany menstruation; these may be diffused over the whole abdomen, or may predominate in the two hypochondriac regions. Disorders of the sense-organs sometimes occurring during menstruation are, the flickering of objects before the eyes, photophobia, and tinnitus aurium. The heart may also be affected with palpitation in association with these nervous disturbances; the stomach may exhibit associated disorder in the form of cardialgia, or more frequently in the form of vomiting, this latter being very frequent at the outset of the flow. Less common is profuse diarrhœa, pain in the anus, or spasm of the sphincter ani.
The intensity of such nervous manifestations during menstruation is dependent upon the woman’s general state of nutrition, upon the degree of instability of her nervous system, and upon her occupation. Robust and powerful women, regularly employed in the open air, such as the wives and daughters of farmers and agricultural laborers, are much less affected by the nerve-weakening influences of menstruation than the sedentary and anæmic town-dwelling women, whether these latter belong to the higher classes of society and are addicted to nerve-straining enjoyments, or to the class of shop-girls, seamstresses, and factory-women, whose employment is apt to lead to nervous exhaustion.
As regards the forms of neuralgia most apt to accompany menstruation, Windscheid mentions trigeminal neuralgia as the commonest, especially affecting the first division of the nerve, and producing localized pains which are to be distinguished from the headaches already mentioned. They are characterized by their intensity and their persistence in spite of anti-neuralgic treatment, and by their spontaneous disappearance as soon as menstruation is over. According to the same author, the relations between hemicrania and the process of menstruation are indisputable; at the very least it must be admitted that menstruation predisposes to an attack of hemicrania.
Cases also occur in which convulsions almost invariably accompany menstruation, convulsions which are to be regarded as symptoms of hysteria.
The extraordinarily powerful influence which the menstrual stimulus exercises on the mind is shown by the frequency with which the slighter psychopathic states occur as an accompaniment even of normal menstruation, these manifestations being sometimes melancholic in type, sometimes maniacal or erotic, and, when of long duration, leading ultimately to pronounced mental disorder. This influence of the menstrual stimulus is yet more potent in cases in which important changes in the course of menstruation have occurred, in cases, for instance, of suppressed, painful, or irregular menstruation. In this connection, however, in order to avoid a confusion of cause and effect, we must carefully bear in mind, that it is a much commoner causal sequence for psychical disorders to disturb the normal course of menstruation, than for disorders of menstruation to evoke psychical disorders. This view has only quite recently become established, and for this reason it is necessary to regard such data when obtained from the writings of the older gynecologists in a somewhat critical spirit.
By the modern alienist, the influence of the menstrual reflex on mental affections is recognized only in cases in which a proper valuation of the predisposing causes has been made, in such cases as the following: First, we have to recognize the modifying influence exercised by the menstrual stimulus on established psychoses, inasmuch as these latter not infrequently undergo cure when previously irregular menstruation has become regular, and, moreover, the recurrence or the first appearance of menstruation has often a powerful influence on the course of some established mental disorder. In some cases this influence is a strikingly favorable one on psychoses that have developed before the commencement of menstruation, or during the suppression of that function; it may be, however, and, indeed, more frequently is, an unfavorable influence, inasmuch as such a psychosis, on the first appearance or on the reappearance of menstruation, may assume a menstrual type, the attacks becoming more frequent or more violent with the successive recurrence of each menstrual or premenstrual period. This is the history of the typical menstrual psychosis.
Again, certain processes of the sexual life, disorders of menstruation, diseases of the genital organs, operations on these organs, and the processes of the climacteric, influence the origin and the character of mental disorder, generally giving rise to chronic affective insanity (insanity of the emotions and feelings) or to paranoia (chronic delusional insanity, insanity of the intellect). The menstrual stimulus must in these cases be regarded as a psychopathically exciting physical cause.
Further, physical disturbances may equally affect the menstrual function and the functions of the mind, rendering the exact causal sequence in such cases a difficult one to determine; and, conversely, the circumstances that restore the normal working of the mind may also regulate the menstrual function.
Finally, we may have to do with isolated sporadic occurrences in which the exciting influence of menstrual processes may be traced. Thus, for the outbreak of a periodical menstrual psychosis, an especial temporal predisposition must exist, connected with the great developmental epoch of the sexual life.
There is, for instance, a group of transitory states occurring during menstruation, and taking the form of disorders of the intelligence or of explosive emotional states; such may be witnessed, not in those suffering from psychopathic predisposition, but in quite healthy individuals.