Incoherence of Thought

INCOHERENCE OF THOUGHT (incoherales Denken), a symptom described by some German psychiatrists as characteristic of a number of conditions accompanied by clouding of consciousness and most often developing in infectious and intoxication psychoses, which has not yet been studied patho-anatomically. In a less pronounced form, it is inherent in states of mental exhaustion due to extreme overwork or insomnia, and is also often observed in perfectly healthy people before falling asleep: thoughts cease to obey the directing influence of attention, which proves unable to remain fixed on anything specific, and goal-directed thinking gives way to associations based on external similarity and sound, which rapidly replace one another, as a result of which correctly constructed thoughts become mixed with fragmentary, often distorted and absurd images; frequently one of the latter acquires a tendency to insistent repeated occurrence {perseveration, see}. By voluntary effort, it is sometimes possible to achieve clarification of thoughts, but, except in cases of normal falling asleep, only for a very brief moment.