5 ideas
The 19th-century Bengali saint Ramakrishna fell into ecstatic trances, had visions of the goddess Kali, and for periods dressed and lived as a woman. Many contemporaries, and later Western commentators, called this madness.
Mystic and psychotic can dissolve the ordinary ego into similar states, so the content of an experience cannot tell them apart. What differs is whether the person can enter the state and come back, whether the experience is integrated into a functioning life, and whether a tradition supplies a map that gives the state a place. Without those three, the same experience becomes breakdown.
Pir, tantric, vaid and psychoanalyst all do the same basic work. Each takes a person's diffuse suffering and places it inside a shared explanatory story, whether that story names spirits, bodily humours, karma or unconscious conflict. Each then works through an idealized, authority-laden relationship. Healing depends less on whether the explanation is literally true than on patient and healer believing in the same meaning-system, so each method is effective within its own culture and falters outside it.
Indian cultural psychology treats the person as embedded in family, caste and cosmos, so health means restoring one's proper place in a web of relationships. Western psychoanalysis treats health as autonomy and individuation. The mismatch means that importing therapy unchanged can pathologize normal interdependence, while traditional healing can miss the costs of that same interdependence.
Spirit possession gives a person, often a young woman in a constrained household, a way to voice forbidden anger, sexuality or grievance as belonging to an outside spirit rather than to herself. Exorcism rituals work by bringing that spirit into public, making it speak, and bargaining with it. The family can then acknowledge the conflict and renegotiate it without anyone being blamed.