A mental disorder characterized by heartlessness or a lack of emotions is called "psychopathy" or "antisocial personality disorder" (ASPD). It is essential to note that the terms "psychopathy" and "antisocial personality disorder" are not entirely interchangeable, but they share some overlapping features.
Psychopathy is a personality disorder characterized by a pervasive pattern of callous disregard for and violation of the rights of others. People with psychopathy often lack empathy, have shallow emotions, and display manipulative and impulsive behavior. They may have a charming and superficially engaging demeanor but lack true emotional connections with others.
Antisocial personality disorder (ASPD) is another personality disorder characterized by a consistent disregard for the rights of others. People with ASPD may exhibit similar traits to psychopaths, such as a lack of empathy and a diminished capacity for emotional depth. However, not all individuals with ASPD display the same level of interpersonal manipulation and charm commonly seen in psychopathy.
Both psychopathy and antisocial personality disorder are associated with a lack of remorse, deceitfulness, impulsivity, and a tendency to engage in irresponsible and sometimes criminal behavior. It's essential to remember that the diagnosis and assessment of personality disorders, including psychopathy and antisocial personality disorder, should be done by qualified mental health professionals using comprehensive evaluation methods. Treatment for these disorders can be challenging and often requires specialized interventions.