Transient depersonalization/ derealization symptoms lasting hours to days are common in the general population. The 12-month prevalence of depersonalization/derealization disorder is thought to be markedly less than for transient symptoms, although precise es- timates for the disorder are unavailable. In general, approximately one-half of all adults have experienced at least one lifetime episode of depersonalization/ derealization. How- ever, symptomatology that meets full criteria for depersonalization/derealization disor- der is markedly less common than transient symptoms. Lifetime prevalence in US. and non-U.S. countries is approximately 2% (range of 0.8% to 2.8%). The gender ratio for the disorder is 1:1.
The mean age at onset of depersonalization/ derealization disorder is 16 years, although the the symptoms. Less than 20% of individuals experience onset after age 20 years and only 5% after age 25 years. Onset in the fourth decade of life or later is highly unusual. Onset can range from extremely sudden to gradual. Duration of depersonalization/derealization disorder episodes can vary greatly, from brief (hours or days) to prolonged (weeks, months, or years). Given the rarity of disorder onset after age 40 years, in such cases the in- dividual should be examined more closely for underlying medical conditions (e.g., brain lesions, seizure disorders, sleep apnea). The course of the disorder is often persistent.
About one-third of cases involve discrete episodes; another third, continuous symptoms from the start; and still another third, an initially episodic course that eventually becomes continuous.
While in some individuals the intensity of symptoms can wax and wane considerably, others report an unwavering level of intensity that in extreme cases can be constantly pres- ent for years or decades. Internal and external factors that affect symptom intensity vary between individuals, yet some typical patterns are reported. Exacerbations can be trig- gered by stress, worsening mood or anxiety symptoms, novel or overstimulating settings, and physical factors such as lighting or lack of sleep.
Temperamental. Individuals with depersonalization/derealization disorder are charac- terized by harm—avoidant temperament, immature defenses, and both disconnection and overconnection schemata. Immature defenses such as idealization/devaluation, projec- tion and acting out result in denial of reality and poor adaptation. Cognitive disconnection schemata reﬂect defectiveness and emotional inhibition and subsume themes of abuse, ne- glect, and deprivation. Overconnection schemata involve impaired autonomy with themes of dependency, vulnerability, and incompetence.
Environmental. There is a clear association between the disorder and childhood interper- sonal traumas in a substantial portion of individuals, although this association is not as prev- alent or as extreme in the nature of the traumas as in other dissociative disorders, such as dissociative identity disorder. In particular, emotional abuse and emotional neglect have been most strongly and consistently associated with the disorder. Other stressors can include phys- ical abuse; witnessing domestic violence; growing up with a seriously impaired, mentally ill parent; or unexpected death or suicide of a family member or close friend. Sexual abuse is a much less common antecedent but can be encountered. The most common proximal precipi- tants of the disorder are severe stress (interpersonal, financial, occupational), depression, anx- iety (particularly panic attacks), and illicit drug use. Symptoms may be specifically induced by substances such as tetrahydrocannabinol, hallucinogens, ketamine, MDMA (3,4-methylene— dioxymethamphetamine; ”ecstasy”) and salvia. Marijuana use may precipitate new-onset panic attacks and depersonalization/derealization symptoms simultaneously.