Inhibited thinking as a normal psychological phenomenon has to be distinguished from psychopathologically defined thinking disorders. Normal psychological inhibitions of thinking can be subdivided into affect-induced inhibitions ("affective inhibitions of thinking") and those caused by habituated thinking or sets ("habitual inhibitions"). In affective inhibitions of thinking, a person who is in a state of affective arousal cannot solve a problem which he usually, i.e. in view of his intellectual capacity, is able to solve. Both the quantitative and qualitative aspects of inhibited thinking can be reliably identified by means of rearrangement tasks administered under adequate situative conditions. In several studies, carried out in various groups of subjects, marked decreases in problem solving performance occurred as a consequence of affective inhibitions of thinking. Disorganized thinking which is a typical result of affective inhibitions of thinking, can either be manifested in form of extremely rigid or chaotic behaviour. First results on the individual tendency towards or proneness to affective inhibitions of thinking and their relationship to personality traits are presented. --Based upon these findings on inhibited thinking, general conclusions are drawn for both the psychology of thinking and psychological diagnostics.