Parts work: definition and where it comes from

Parts work is an umbrella term for therapies built on one idea: the mind is made of distinct “parts,” each with its own feelings and role, not one unified voice. It treats inner conflict as protective and workable, not a flaw. Internal Family Systems (IFS) is the best-known modern form, but the tradition is older and wider than IFS alone.

Where does the idea of “parts” come from?

The idea has several independent roots, decades apart. Italian psychiatrist Roberto Assagioli was already writing about “subpersonalities” by 1911. He later built the idea into psychosynthesis, the model he founded in 1926.

Psychiatrist Eric Berne took a narrower version mainstream in the 1950s. His transactional analysis named three ego states, Parent, Adult, and Child, per the International Transactional Analysis Association. Psychoanalyst Paul Federn had described a related “ego state” concept even earlier. In the 1970s, John and Helen Watkins built that lineage into ego-state therapy, using hypnosis to work directly with different states, per a 2018 history in the International Journal of Clinical and Experimental Hypnosis. Psychologists Hal and Sidra Stone developed a parallel model the same decade, called Voice Dialogue.

Internal Family Systems arrived later, in the early 1980s, and became the most widely practiced version of the idea.

Is “parts work” the same thing as IFS?

Not quite, though the terms get used interchangeably online. IFS is the most popular current model, but it’s one branch of a wider tradition that also includes ego-state therapy, Voice Dialogue, and psychosynthesis, some of it 70 years older than IFS. Each treats a part’s behavior, even a self-critical one, as once-protective, not as something to fight.

How does this connect to EMDR?

EMDR doesn’t use “parts” language in its own core protocol. But its theory, the Adaptive Information Processing model, rests on a similar premise, per EMDRIA: patterns that show up today usually trace back to earlier experience that never fully settled. For complex trauma and dissociation specifically, some EMDR clinicians directly integrate ego-state and parts-informed strategies, stabilizing a client’s internal system before reprocessing begins. Our EMDR vs. parts work comparison goes deeper on how the two approaches combine.

Can you try parts work on your own?

Gently, for everyday use. Simply noticing a reaction with curiosity, “part of me is furious, part of me just wants this over,” instead of arguing with it, is the core move most of these models share.

EmEase, a self-guided EMDR app, offers bilateral stimulation, the technique behind EMDR, as a way to settle the emotional charge that kind of noticing can bring up. Try it at app.emease.com. If a part is carrying real trauma or dissociation rather than everyday friction, that’s a cue to work with a therapist trained in these approaches instead.

And if the “parts” framing resonates, your inner child is a closely related idea worth a look.