Stress and anxiety can trigger perseveration, or at the very least make it worse. Brain injury is just one of a variety of conditions in which perseverative disorders can occur. Others include Alzheimer’s disease, aphasia, schizophrenia and Parkinson’s disease.
An example of perseveration is someone sandpapering a table until they go through the wood, or a person who continues talking about a topic even when the conversation has moved on to other things. Another person might be asked to draw a cat, then several other objects, but continue to draw a cat each time.