Automaton, plural automata: one who behaves or responds in a mechanical way.
Automata, also known as tick-tocks, suffer from a rare* Muttiverse mental illness that affects any of Shade's Five Races (incidence slightly higher in humans and trolls) and sapient species from some other planets.
*(fewer than 1 in 100,000)
Sufferers tend to be unnaturally still and unresponsive for most of the time. This is similar to a catatonic stupor except that the patient will usually be roused to action by a particular goal or duty, usually one that was held in some degree of importance before the onset of the condition. When in their active state, they tend to move in sudden bursts, which is very unnerving.
The condition also differs from catatonic stupor in that the patient will usually perform unprompted the minimum tasks to keep themselves alive, may often keep themselves very clean and neat, and may even practice physical exercises for hours at a time. There is often a sense of waiting for something, and sufferers are called 'awaiters' or 'sleepers' in some cultures.
Automata are often mute, though there is no physical reason they cannot talk. Telepathic healers who try to read them often feel repulsed by the 'unnatural' brainwaves and refuse to continue. Those who persevere have reported impressions like these: the patient is "not thinking", "barricaded in", "resting on instincts" or "on auto pilot". Some patients (perhaps those with telepathic skill, but that's not proven) seem to interpret telepathy as an attack and retaliate.
For trauma-induced cases, addressing the cause is key. Drug therapies (not investigated until several decades post-War).
For goal-focused cases (the majority), removing or accomplishing the goal may have an unpredictable effect, from suicide to partial recovery, or may cause no change.