ICD-116B66	DEPERSONALIZATION-DEREALIZATION DISORDER Depersonalization-derealization disorder
ICD-10F48.1	Depersonalization-derealization syndrome
DSM-5-TRF48.1	Depersonalization/Derealization Disorder

1. Definition and nosology

Depersonalization-Derealization Disorder (ICD-11: 6B66; DSM-5-TR: F48.1) — a dissociative disorder characterized by persistent or recurrent depersonalization (feeling detached from oneself, disconnected from body and thoughts) and/or derealization (surroundings appearing unreal, like a ‘foggy film’). Reality testing is preserved (the patient knows the experience is unreal).

2. History

• Krishaber M. (1872) — first description.
• Dugas L. (1898) — term ‘dépersonnalisation’.
• DSM-III (1980) — Separate diagnosis.
• DSM-5 (2013) — depersonalization and derealization as a combined category.

3. Epidemiology

• Lifetime prevalence: 1–2% in clinical form; subclinical experiences at least once in 50% of the population.
• Gender: approximately equal.
• Onset: adolescence and early adulthood (mean 16 years).
• Comorbidity: MDD, panic, GAD, PTSD, BPD.

4. Aetiology and pathogenesis

• Trauma and stress trigger (especially cannabis, hallucinogen use).
• Neurobiological — impaired prefrontal-limbic regulation; sensory processing anomalies (Simeon D. reviews).
• Comorbid anxiety and panic attack frequency high.

5. Clinical features

• Depersonalization: Sense of observing oneself from outside, feeling like a robot, emotional flattening, feeling that “my body is not mine”.
• Derealization: Environment appears “faded”, “like a faded film” or “artificial”; distance perception change.
• Reality testing preserved — patient knows the experience is unreal.
• Significant distress and functional impairment.
• Typical course — continuous or recurring episodes.

6. Diagnosis

6.1 Unified diagnostic criteria

A. Persistent or recurrent experiences of depersonalization and/or derealization.

B. Reality testing preserved.

C. Significant distress or functional impairment.

D. Exclusion of substance (cannabis, hallucinogen) or medical condition (seizure, brain injury).

E. Not better explained by another mental disorder (transient during panic attack; in context of PTSD; schizophrenia).

6.2 Source-specific clarifications

• DSM-5-TR / ICD-11 — same criteria.

6.3 Diagnostic algorithm

1. Clinical interview.
2. CDS (Cambridge Depersonalisation Scale, Sierra M., Berrios G.E.) — 29 items.
3. Medical and neurological examination (excluding seizures and brain injury).
4. Toxicology screening.
5. Comorbidity.

6.4 Differential diagnosis

7. Examination and assessment

• CDS is the gold standard.
• EEG if seizure is to be ruled out.
• Toxicology.

8. Treatment

1. CBT — adapted for depersonalization; cognitive restructuring + exposure. Hunter E.C. et al. Behav Res Ther 2005.
2. SSRI — effective for comorbid depression and anxiety; evidence base for disorder itself limited.
3. Lamotrigine adjunct — effective in some studies.
4. Against trauma background — trauma-focused approach.
5. Abstinence from cannabis and hallucinogen use is critical.

Source-specific specifications

• Sierra M. reviews — CBT and adjunctive SSRIs.
• There is no specific FDA-approved medication.

Treatment methods

1. CBT for depersonalization — Hunter (Hunter E.C.), Sierra (Sierra M.) — Cognitive restructuring, exposure, grounding techniques.
2. Cambridge Depersonalisation Scale (CDS) — 29 items.
3. Grounding techniques — 5-4-3-2-1 (5 visible objects, 4 sounds, etc.); sensory attention.

9. Prognosis

• Chronic course, but significant improvement with CBT.

10. Myths and misconceptions

Myth 1: “Depersonalization is a sign of psychosis”

Evidence: Reality testing preserved; distinct from psychotic disorder; antipsychotic ineffective.

Myth 2: “Depersonalization is transient and does not require treatment”

Evidence: Clinical form features chronic course and functional impairment; intervention recommended.

Myth 3: “Cannabis improves depersonalization”

Evidence: Cannabis is a trigger and perpetuating factor; abstinence critical.

Myth 4: “Benzodiazepines are the main treatment”

Evidence: benzodiazepine provides short-term relief, but risk of dependence and depersonalization enhancement.

Myth 5: “Only antidepressants are effective”

Evidence: CBT first-line; SSRIs for comorbid symptoms.

11. Sources

1. WHO. ICD-11. 6B66 Depersonalization-derealization disorder. 2024.
2. APA. DSM-5-TR. 2022.
3. Sierra M. Depersonalization: A New Look at a Neglected Syndrome. Cambridge Univ Press; 2009.
4. Hunter E.C.M. et al. Cognitive-behaviour therapy for depersonalisation disorder: an open study. Behav Res Ther 2005;43(9):1121–1130.
5. Simeon D. Depersonalisation disorder: a contemporary overview. CNS Drugs 2004;18(6):343–354.
6. Sierra M., Berrios G.E. The Cambridge Depersonalisation Scale: a new instrument for the measurement of depersonalisation. Psychiatry Res 2000;93(2):153–164.