Malignant narcissism is a psychological syndrome comprising an extreme mix of narcissism, antisocial behavior, aggression, and sadism. Grandiose, and always ready to raise hostility levels, the malignant narcissist undermines families and organizations in which they are involved, and dehumanizes the people with whom they associate.

Malignant narcissism is not a diagnostic category, but a subcategory of narcissism. Narcissistic personality disorder (NPD) is found in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR), while malignant narcissism is not. Malignant narcissism could include aspects of narcissistic personality disorder (NPD) alongside a mix of antisocial, paranoid and sadistic personality disorder traits. The importance of malignant narcissism and of projection as a defense mechanism has been confirmed in paranoia, as well as "the patient's vulnerability to malignant narcissistic regression". A person with malignant narcissism exhibits paranoia in addition to the symptoms of a Narcissistic Personality Disorder. Because a malignant narcissist's personality cannot tolerate any criticism, being mocked typically causes paranoia.