Cognitive Disorders and Madness Powers

This is the mechanical heart of Psycho-Sleuth. The disorder is the character; the madness power (病能) is what the disorder does to the screen you are looking at.

The confirmed disorder set

• Synesthesia (聯覺症) — Lain's condition. His power of World Creation lets him impose his hallucinations onto other people's perception. The most dangerous power in the room, because it works through other people.
• OCD / 禁謊 — Reina's condition; she cannot lie. She is therefore either the most reliable witness in the cathedral or a person whose every word is a constraint she did not choose.
• Hemispatial neglect — the left half of the screen is hidden. You are working from partial information, and you have to work out what is off-screen from what is on it.
• Prosopagnosia — faces read as blank. Identity has to be carried by everything except the face, which reframes the entire murder when a corpse is on the floor.
• Hyperthymesia — perfect recall. A witness who cannot forget is a witness who cannot be dismissed, which changes the whole shape of the debate.
• Alice in Wonderland syndrome — reality and scale shift in the character's perception. A dreamlike distortion the player experiences directly.
• Acropagnosia — the acral, hands and feet, become unreadable. Detail you would take for granted disappears, and detail you would have missed becomes the only thing there is.

Contagion

The powers are described as contagious, and Chapter 2 (「扭曲證詞」) turns that into the central mechanic. The contagion adds symptoms to other characters, which adds new dialogue, which changes what the evidence means. A disorder that started as one character's problem becomes a condition of the whole room.

Why clinical accuracy matters here

The game's disorder set is drawn from genuine neuropsychology, and the presentation respects it: the effects are disabling rather than dramatic, and they interfere with the player's ability to gather information rather than simply making a character cooler. That is why the game works as a deduction game — every disorder removes a channel of evidence, so you have to reason around the gaps.