Several hundred named psychotherapies are in circulation, many overlapping heavily. The proliferation is a feature of how the field is organised rather than of how many distinct methods exist.
Nothing prevents founding a modality
Creating a named approach requires no approval from any body. A practitioner can describe a method, write about it and begin training others.
Unlike a medicine, a therapeutic approach faces no pre-market authorisation, so the barrier is persuasion rather than evidence.
Where a field has no gatekeeper for new entries, the number of entries grows, and the field's history reflects exactly that.
Naming a method creates a training business
An unnamed set of techniques cannot be taught as a certified course. A named modality can, with levels, accreditation and a register of practitioners.
Training income is often more reliable than clinical income, and it scales in a way that seeing clients individually does not.
The incentive therefore runs strongly toward differentiation, since a method presented as a variation of an existing one cannot support its own training structure.
Splitting from a predecessor is the common pattern
Most modalities emerged from an existing tradition after a disagreement about technique, emphasis or theory.
The founder typically retains most of the parent method while foregrounding the point of departure, which is what gives the new approach its identity.
Tracing the lineages produces a family tree in which large branches share far more with each other than their separate names suggest.
Common factors research complicates the picture
A long line of comparative research has found that different approaches often produce broadly similar outcomes for many presenting problems.
The elements that appear to matter most are shared across approaches: the relationship, a credible rationale, agreement on goals and the fact of regular attendance.
If much of the effect is carried by shared elements, then the proliferation of names describes professional organisation more than it describes distinct treatments.
Integration is where most practitioners actually sit
Surveys of practising therapists consistently find that a large share describe themselves as integrative rather than working within one named model.
In practice they draw on several approaches according to the person in front of them, which is what experience tends to produce.
The named modalities therefore function largely as training routes and as vocabulary, while the work itself is less divided than the labels imply.