In the experience of all alienists, it is, speaking generally, the inherited psychopathic tendency that especially manifests itself at the time of puberty; and it appears that this predisposition, the manifestations of which the resisting powers of childhood have hitherto been competent to suppress, undergoes a sudden and stormy development in consequence of the action of the menstrual stimulus, leading to the unexpected appearance of mental disorders. The commonest of these are mania and melancholia of the ordinary type, the prognosis in first attacks being favorable; next in frequency to these are the psychoses characterized by fixed ideas, which usually terminate favorably after a short time; finally, we meet with the moral psychoses of puberty, and the form of melancholia distinguished by _Kahlbaum_ as _Hebephrenie_,[23] the prognosis of which is very unfavorable, for it speedily terminates in dementia, similarly to the dementia of puberty described by _Svetlin_, dependent upon or associated with premature synostosis of the cranial bones. Very often we witness at puberty the beginning of the periodic varieties of mental disorder, which develop into periodic menstrual psychoses, manifesting themselves regularly at the recurrence of every menstrual period. The fact that hysteria often first manifests itself at the time of the first appearance of menstruation was noticed already by _Hippocrates_, who indeed believed that the association was sufficiently explained by the well-known manifold relations between this nervous disease and disturbances in the female genital organs. The first hysterical attack often coincides with the first menstruation; or the first menstruation may lead to the recrudescence of hysteria which had manifested itself previously, but had passed into abeyance. We have to deal chiefly with the minor forms, such as uncontrollable and unconditioned attacks of laughing and crying, globus hystericus, clavus hystericus, etc.; hysteria major, on the other hand, is very seldom observed at the time of the menarche. As regards the frequency of hysteria at the time of puberty, we append certain statistical data. _Landouzy_ found: 4 cases of hysteria occurring at the ages of 1 to 10 years. 45 cases of hysteria occurring at the ages of 10 to 15 years. 105 cases of hysteria occurring at the ages of 15 to 20 years. 80 cases of hysteria occurring at the ages of 20 to 25 years. After the age of twenty-five is attained, the frequency of hysteria declines very rapidly.