Dionysian madness is a trance of ego death through ecstasy, shedding control, tapping into primal memory, unleashing repressed emotion. It teaches by chaos, heals through shadow. A forest fire of the soul: destroy to renew, descend in the underworld to rise again, greater.
Dionysus is the liberator, but how so?
The point of Dionysian madness is to enter a trance, to temporarily dissolve the ego, to lose control, and return to an animalistic state outside of individuation. In this state of dissolution, the individual does not exist; he is one with the world.
First, this state of consciousness is conducive to "blood memory" resurfacing (archetypal, instinctive wisdom, essentially) on themes such as death, rebirth, divine love, chaos, destruction, renewal, and more, similarly to a psychedelic trip.
This state also allows for catharsis through revelry. For example, some Dionysian rituals would involve animal sacrifice and a sparagmos (the dismemberment of the animal by hand). This can also take the form of more symbolic acts, allowing for the expression of repressed emotions. It is a way to shed what the Orphics called our “Titanic nature” (of the same essence as the Titans), in order to purify oneself. Getting rid of the "miasma", impurities on the subtle body.
At the same time, this return to an animalistic self is essential for letting go of conditioning imposed on one's psyche (be it social norms or even language itself) allowing access to thoughts that are ineffable and to embrace the non-dualistic relation between the horror and beauty of existence.
Shedding all constraints and embodying a deeper, more primordial part of the psyche also allows one to tap into the Jungian shadow and the unconscious, which holds immense psychological healing potential. Dionysian madness teaches the irrational, irrationally, by immersing oneself in primordial chaos, aiding in the shedding of one’s old skin. It is, in a sense, like tending the garden of the mind, but like a forest fire whose ashes allow for new growth. A descent into the underworld from which one returns changed.