A defense mechanism where one abandons adult coping strategies in favor of earlier, more childlike patterns of behavior. Anna Freud was the person who coined this word. She believed that people tended to act out the stage in which their mind was stuck. A person could be stuck (Anna called this “fixated”) in one of two phases (the phase on which the person is fixated greatly changes the way the person acts).

The first stage is called the oral fixation phase in which the patient might begin smoking overeating or chainsmoking. They could also become verbally agressive and yell at others. The second stage is called the anal fixation phase and is characterized by such behavior as cleaning much more than usual or becoming completely messy.

Example: After a stressful day, a 10-year-old boy reverts to his childhood habit of thumb-sucking.