Psycho-ANALYSTS and other psychiatrists agree, I take it, that there are multiple causes for every mental breakdown. The exciting cause may not always be discoverable, but would be sought, if wanted, in the period immediately preceding the onset. Contributory causes can occur throughout life, from birth to the date of onset. It is agreed, also, that in addition there must be a predisposition (though the strength of this as a causal factor varies, roughly, in inverse proportion to the others). It is in the localization of the predisposing (and specific) factors that authorities differ. The older psychiatrists confined it to the lifetime of the ancestors; psychoanalysts accept, in general, what they have been told about ancestral responsibility, but have focused attention, as regards predisposition for subsequent breakdown, on a later period, namely the first five or six post-conceptional years. This they regard as the developmental period of the psyche, and they consider that influences at this time modify the organization in process of formation in a way that cannot occur later, but is not entirely predetermined in the germ-plasm. The difference is not merely temporal but also qualitative, for while other causes are mainly general (with perhaps some exception as regards heredity), the infantile predispositions are specific. That is, they not only partly determine liability to a breakdown under stress, but play the chief part in determining the kind of breakdown to be expected should one occur, and also the basic layers on which various character formations are built, although the superstructures may be very varied.