What defense mechanism refers to a hospitalized 10-year-old who begins to wet his bed?

The scenario described involves a 10-year-old child in the hospital who begins to wet the bed, which is indicative of a return to an earlier developmental stage. This behavior aligns with the concept of regression, a defense mechanism in which individuals revert to behaviors characteristic of an earlier point in development when faced with stress or anxiety.

In children, such regression often occurs during times of distress, such as illness, hospitalization, or significant changes in their environment. By regressing to bedwetting, the child may be unconsciously seeking comfort and security associated with a younger age, reflecting an inability to cope with the current psychological stressors they are facing. This mechanism is a way for the child to cope with a new and intimidating situation, demonstrating a temporary retreat into past behaviors that provided a sense of safety and control.

The other options describe different defense mechanisms. Displacement involves redirecting feelings from one target to another, reaction formation involves expressing the opposite of one's true feelings, and isolation involves separating feelings from thoughts. None of these accurately describe the behavior of bedwetting in the given context as well as regression does.