This document discusses defense mechanisms, which are unconscious psychological mechanisms that help reduce anxiety arising from unacceptable thoughts or impulses. It defines defense mechanisms and provides examples of common ones such as rationalization, regression, sublimation, withdrawal, displacement, denial, fantasy, compensation, repression, reaction formation, projection, and intellectualization. The document emphasizes that defense mechanisms can be adaptive in moderating anxiety but using them excessively can become maladaptive. It also notes the importance of nurses understanding patients' defense mechanisms and helping discourage maladaptive ones in favor of adaptive coping strategies.