Character perpetually convinced of being ill — creates internal tension and dark comedy simultaneously. Hitchcock exploited this brilliantly for psychological suspense.
The hypochondriac on set is a character who makes themselves the scene — it's not the body that's of interest, but the obsessive fear of its decay. This is dramatically valuable because the internal turmoil is pushed outward. You see it immediately in the performance: the actor must constantly listen to themselves, check every pulse, evaluate every twitch. This creates a body language that oscillates between hypersensitivity and paranoia.
Hitchcock used this elegantly — not as a main theme, but as a character trait that makes a figure vulnerable precisely when danger becomes real. The viewer doesn't know if the fear is justified or a projection. This creates psychological friction. Billy Wilder, on the other hand, cultivated the hypochondriac as a source of comedy: the man who imagines he's dying while the world collapses around him — the discrepancy between imagined and real crisis produces laughter. This works because we all know this impulse to see our body as an enemy.
For the camera, this means concretely: you have to make this internal attention visible. Close enough to capture micro-expressions — the rolling of the eyes, the furrowing of the brow, the hand involuntarily going to the temple. Movements are often circular, repetitive: the same check, the same concern. This distinguishes the hypochondriac from the depressive or anxious character — it's less melancholic than self-absorbed in their own bodily crisis. They are a spectator of themselves. In editing, this can be intensified through frequent, quick cuts between their worried expression and what triggers it — an itch becomes a lesion, a heartbeat an infarction. Hypochondria is not a loss of reality, but a heightened perception of the wrong things. This makes it psychologically interesting and visually tangible.