Chapter 3. History of Dissociation (2) From Hysteria to Dissociation (15)

In 1913, in “On Psychoanalysis” he clearly states.
Psycho-analysis soon found itself in sharp opposition to Janet's views，be cause (a) it declined to trace back hysteria directly to congenital hereditary degeneracy，(b ) it offered，in stead of a mere description，a dynamic explanation based on the interplay of psychical forces and (c) it ascribed the origin of psychical dissociation (whose importance had been recognized by Janet
as well)not to a [failure of] mental synthesis resulting from a congenita1 disability， but to a special psychical process known as “repression” ('Verdrangung”).(SE.12,1913, p.207)
To summerise, this is what Freud is saying. When our mind separates something from our consciousness, we exercise a psychical force to drive it away into the unconscious. This is the mechanism of repression in the context of dynamic perspective, that is incompatible with Janet’s idea of dissociation that is mobilized without psychical force and is attributed to the genetic deficit in the syntetic ability.
We notice that this is what Freud was dissastisfied with Breuer’s theory about when they wrote “Studies of Hysteria” (Freud, Breuer, 1895.) He was not happy that Breuer called the state of Anna O as “hypnoid hysteria” as this notion was not dynamic.
In his view what happens in hypnoid hysteria is that an idea becomes pathogenic because it has been received during a special psychical state and has from the first remained outside the ego. No psychical force has therefore been required in order to keep it apart from the ego and no resistance need be aroused if we introduce it into the ego with the help of mental activity during somnambulism.(Studies on Hysteria, SE 2, p286)
According to Freud such cases should be understood as defense hysteria. This discussion indicates again that Freud was stressing the importance of dynamic aspects of the mind (repression, defense, etc) and he was skeptical about theory of dissociation mobilized without these forces
What Freud was preoccupied with when he abandoned the sexual seduction theory was the resistence that his patients showed when they were instructed to free associate, and to talk about their hidden drives and past traumatic memories. On the one hand they want to follow the instruction of free association to reveal them, but on the other hand they invariably have a strong resistance toward becoming conscious of any of them.