Volitionally induced experiences of depersonalization/ derealization can be a part of med- itative practices that are prevalent in many religions and cultures and should not be diag- nosed as a disorder. However, there are individuals who initially induce these states related practices.
Symptoms of depersonalization/ derealization disorder are highly distressing and are as- sociated with major morbidity. The affectively ﬂattened and robotic demeanor that these individuals often demonstrate may appear incongruent with the extreme emotional pain reported by those with the disorder. Impairment is often experienced in both interpersonal and occupational spheres, largely due to the hypoemotionality with others, subjective diffi- culty in focusing and retaining information, and a general sense of disconnectedness from life.
Illness anxiety disorder. Although individuals with depersonalization/derealization dis- order can present with vague somatic complaints as well as fears of permanent brain dam- age, the diagnosis of depersonalization/derealization disorder is characterized by the presence of a constellation of typical depersonalization/derealization symptoms and the ab- sence of other manifestations of illness anxiety disorder.
Major depressive disorder. Feelings of numbness, deadness, apathy, and being in a dream are not uncommon in major depressive episodes. However, in depersonalization/ derealization disorder, such symptoms are associated with further symptoms of the dis- order. If the depersonalization/ derealization clearly precedes the onset of a major depres- sive episode or clearly continues after its resolution, the diagnosis of depersonalization/ derealization disorder applies.
Obsessive-compulsive disorder. Some individuals with depersonalization/ dereal- ization disorder can become obsessively preoccupied with their subjective experience or develop rituals checking on the status of their symptoms. However, other symptoms of obsessive-compulsive disorder unrelated to depersonalization/derealization are not present.
Other dissociative disorders. In order to diagnose depersonalization/ derealization disorder, the symptoms should not occur in the context of another dissociative disorder, such as dissociative identity disorder. Differentiation from dissociative amnesia and con- version disorder (functional neurological symptom disorder) is simpler, as the symptoms of these disorders do not overlap with those of depersonalization/ derealization disorder.
Anxiety disorders. Depersonalization/derealization is one of the symptoms of panic at- tacks, increasingly common as panic attack severity increases. Therefore, depersonal— ization/derealization disorder should not be diagnosed when the symptoms occur only during panic attacks that are part of panic disorder, social anxiety disorder, or specific phobia. In addition, it is not uncommon for depersonalization/derealization symptoms to first begin in the context of new-onset panic attacks or as panic disorder progresses and worsens. In such presentations, the diagnosis of depersonalization/ derealization disorder can be made if 1) the depersonalization/ derealization component of the presentation is very prominent from the start, clearly exceeding in duration and intensity the occurrence of actual panic attacks; or 2) the depersonalization/ derealization continues after panic dis- order has remitted or has been successfully treated.
Psychotic disorders. The presence of intact reality testing specifically regarding the depersonalization/derealization symptoms is essential to differentiating depersonal- ization/derealization disorder from psychotic disorders. Rarely, positive-symptom schizophrenia can pose a diagnostic challenge when nihilistic delusions are present. For example, an individual may complain that he or she is dead or the world is not real; this could be either a subjective experience that the individual knows is not true or a delusional conviction.