Specially designed interviews (such as the SCID-D) and personality assessment tools may be used in the evaluation as well. Since most of the symptoms depend on self-report and are not concrete and observable, there is a degree of subjectivity in making the diagnosis. People are often disinclined to seek treatment, especially since their symptoms may not be taken seriously; thus dissociative disorders have been referred to as "diseases of hiddenness".The diagnosis has been criticized by supporters of therapy as a cause or the sociocognitive hypothesis as they believe it is a culture-bound and often health care induced condition. The social cues involved in diagnosis may be instrumental in shaping patient behavior or attribution, such that symptoms within one context may be linked to DID, while in another time or place the diagnosis could have been something other than DID. Other researchers disagree and argue that the existence of the condition and its inclusion in the DSM is supported by multiple lines of reliable evidence, with diagnostic criteria allowing it to be clearly discriminated from conditions it is often mistaken for (schizophrenia, borderline personality disorder, and seizure disorder). That a large proportion of cases are diagnosed by specific health care providers, and that symptoms have been created in nonclinical research subjects given appropriate cueing has been suggested as evidence that a small number of clinicians who specialize in DID are responsible for the creation of alters through therapy.
Others explain the increase as being due to the use of inappropriate therapeutic techniques in highly suggestible individuals, though this is itself controversial while proponents of DID claim the increase in incidence is due to increased recognition of and ability to recognize the disorder. Figures from psychiatric populations (inpatients and outpatients) show a wide diversity from different countries.A 1996 essay suggested three possible causes for the sudden increase of DID diagnoses, among which the author suspects the first being most likely:
The result of therapist suggestions to suggestible people, much as Charcots hysterics acted in accordance with his expectations. Psychiatrists past failure to recognize dissociation being redressed by new training and knowledge. Dissociative phenomena are actually increasing, but this increase only represents a new form of an old and protean entity: "hysteria".Dissociative disorders were excluded from the Epidemiological Catchment Area Project. North America
DID is considered a controversial diagnosis and condition, with much of the literature on DID still being generated and published in North America, to the extent that it was once regarded as a phenomenon confined to that continent though research has appeared discussing the appearance of DID in other countries and cultures. Although the condition has been described in non-English speaking nations and non-Western cultures, these reports all occur in English-language journals authored by international researchers who cite Western scientific literature and are therefore not isolated from Western influences.