<prompt> Perseveration isRepetition of an activityRepetition of word or a phraseInability to change the mental set in spite of a new stimulusPersistence of uncomfortable posture for long periods  <response>: B Repetition of word or a phrase Perseveration refers to a tendency to present with a point or theme, even after it has been dealt with exhaustively or the listener has tried to change the subject. Perseveration is seen in schizophrenia3 but is not characteristic of this disorder. It also seen in autistic disorders and few other psychosis. It is chracterised by repeatition of thoughts, speech or brief behavioural sequences without a sense of incompletion and not as a preventive or a corrective measure. This implies clearly that it is carried out without any purpose. 