Behavioural sciences for USMLE Step 1

A hospitalised man asks a nurse for pain medication. When she says the next dose is not due for an hour, he says the previous nurse was excellent and understood him, while she clearly does not care about patients. Which defence mechanism is he using?

1. Reaction formation Behaving in a way opposite to an unacceptable impulse, such as being conspicuously kind to someone one resents.
2. Projection Attributing one's own unacceptable feelings to someone else, for example insisting the nurse is angry when it is the patient who is angry.
3. Splitting correct Correct. People and situations are experienced as wholly good or wholly bad, with no capacity to hold both. It is characteristic of borderline personality organisation and it fractures teams, which is why the response is a consistent, unified staff plan rather than individual negotiation.
4. Sublimation A MATURE defence: channelling an impulse into a socially useful outlet. Nothing here is adaptive.
5. Displacement Redirecting an impulse to a safer target, such as shouting at a relative after being frightened by a diagnosis.

The point: Mature defences: sublimation, altruism, suppression, humour. Immature ones dominate exam vignettes. Splitting is the one that shows up as staff conflict on the ward. The management answer is almost always to set consistent limits as a team.

Source: USMLE Content Outline — behavioural sciences NBME / FSMB (USMLE programme) · tier 0, exam blueprint / regulator