Explain why a hypnagogic hallucination, on its own, should generally not be over-interpreted as a sign of psychiatric illness.

Both are common, brief, and, on their own, are not considered a sign of psychiatric illness, and frequently occurs in people with no psychiatric illness at all, and its presence alone should not be over-interpreted. Because these experiences arise specifically during the normal physiological transition between wakefulness and sleep, a period in which the brain's usual mechanisms for distinguishing internally generated activity from genuine perception are naturally somewhat relaxed, their occurrence reflects an ordinary variation in this transitional state rather than an underlying disease process. This matters clinically because a clinician who elicits a single, isolated report of this kind should weigh it very differently from a hallucination occurring during full wakefulness, and should avoid causing unnecessary alarm or over-pathologising a genuinely common and usually benign experience, reserving concern for hallucinatory experiences that occur outside this specific transitional window or that recur persistently during full wakefulness.