Sigmund Freud's theory of psychosexual development describes the anal stage as occurring between 18 months and three years of age. During this period, children derive pleasure from controlling and releasing their bowel movements. However, they quickly learn that societal expectations impose restrictions on when and where this can happen. This stage marks a critical point where children begin to develop a sense of control and mastery over their bodily functions, as well as their broader behaviors and impulses. According to Freud, the way parents handle toilet training plays a central role in shaping a child's personality development.

When parents approach toilet training with encouragement, praise, and patience, children may develop a sense of competence and autonomy. Successfully navigating the anal stage fosters a balanced and healthy personality. In contrast, strict or overly punitive approaches can cause the child to become overly concerned with orderliness and control. This fixation may result in what Freud termed an anal-retentive personality, characterized by extreme neatness, rigidity, and a strong desire for perfectionism.

Conversely, if parents are too lenient or permissive during toilet training, the child may fail to internalize sufficient self-control. Freud suggested that this could lead to the development of an anal-expulsive personality, associated with traits such as disorganization, carelessness, and emotional volatility. As a result, the anal stage, according to Freud, plays a key role in shaping the balance between order and chaos in an individual's personality based on early experiences of control and regulation.