Tests such as the DES provide a quick method of screening subjects so that the more time-consuming structured clinical interview can be used in the group with high DES scores. Depending on where the cutoff is set, people who would subsequently be diagnosed can be missed. An early recommended cutoff was 15–20. The reliability of the DES in non-clinical samples has been questioned. Treatment
Treatment aims to increase integrated functioning. The International Society for the Study of Trauma and Dissociation has published guidelines for phase-oriented treatment in adults as well as children and adolescents that are widely used in the field of DID treatment. The guidelines state that "a desirable treatment outcome is a workable form of integration or harmony among alternate identities". Some experts in treating people with DID use the techniques recommended in the 2011 treatment guidelines. The empirical research includes the longitudinal TOP DD treatment study, which found that patients showed "statistically significant reductions in dissociation, PTSD, distress, depression, hospitalisations, suicide attempts, self-harm, dangerous behaviours, drug use and physical pain" and improved overall functioning. Treatment effects have been studied for over thirty years, with some studies having a follow-up of ten years. Adult and child treatment guidelines exist that suggest a three-phased approach, and are based on expert consensus.
The primary dispute is between those who believe DID is caused by traumatic stresses forcing the mind to split into multiple identities, each with a separate set of memories, and the belief that the symptoms of DID are produced artificially by certain psychotherapeutic practices or patients playing a role they believe appropriate for a person with DID. The debate between the two positions is characterized by intense disagreement. Research into this hypothesis has been characterized by poor methodology. Psychiatrist Joel Paris notes that the idea that a personality is capable of splitting into independent alters is an unproven assertion that is at odds with research in cognitive psychology.Some believe that DID is caused by health care, i.e. symptoms of DID are created by therapists themselves via hypnosis. This belief also implies that those with DID are more susceptible to manipulation by hypnosis and suggestion than others. The iatrogenic model also sometimes states that treatment for DID is harmful. According to Brand, Loewenstein and Spiegel, "[t]he claims that DID treatment is harmful are based on anecdotal cases, opinion pieces, reports of damage that are not substantiated in the scientific literature, misrepresentations of the data, and misunderstandings about DID treatment and the phenomenology of DID".