According to the DSM-5 (code 300.14), a diagnosis of DID requires the presence of at least two distinct personality states (alters) and significant memory disruptions. These memory gaps, which involve difficulty recalling daily events, personal information, or traumatic experiences, must be more severe than ordinary forgetfulness. Furthermore, the symptoms must cause considerable impairment in daily functioning and cannot be attributed to substance use or cultural/religious practices.

Diagnostic and Statistical Manual (DSM-5) Criteria for DID

Some evaluation tools have been made to diagnose DID, including:
- Dissociative Experiences Scale (28 questions);
- Dissociation Questionnaire (63 questions);
- Difficulties in Emotion Regulation Scale (DERS) (36 questions).
In each of these tests, the person answers a set number of questions, making it possible to test different factors often affected by DID. 

Tulane University

A long road precedes diagnosing patients with DID. To do so, a detailed history of the person is compiled by psychiatrists and psychologists using many sources. This is important to avoid misdiagnosing the patient with other personality disorders, which is often the case. Additionally, neurological examinations are needed to make sure the patient does not have autoimmune encephalitis which would attack the brain and cause swelling.

First step in evaluating if a person has DID

Mitra, P., & Jain, A. (2023, May 16). Dissociative Identity Disorder. National Library of Medicine. https://www.ncbi.nlm.nih.gov/books/NBK568768/

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