Query: Dissociative identity disorder (DID) is known as multiple personality disorder (MPD).

Relevant passages:
Dissociative identity disorder <=SEP=> Dissociative identity disorder ( DID ) , also known as multiple personality disorder ( MPD ) , is a mental disorder characterized by at least two distinct and relatively enduring identities or dissociated personality states . These states alternately show in a person 's behavior , accompanied by memory impairment for important information not explained by ordinary forgetfulness . These symptoms are not accounted for by substance abuse , seizures , or other medical conditions , nor by imaginative play in children . Dissociative symptoms range from common lapses in attention , becoming distracted by something else , and daydreaming , to pathological dissociative disorders . Symptoms vary over time .   Dissociative disorders , including DID , have been attributed to disruptions in memory caused by trauma or other forms of stress . Research on this hypothesis has been characterized by poor methodology . An alternative hypothesis is that DID is a by-product of techniques employed by some therapists , especially those using hypnosis , and disagreement between the two positions is characterized by intense debate . DID is one of the most controversial psychiatric disorders , with no clear consensus on diagnostic criteria or treatment . No systematic , empirically supported definition of `` dissociation '' exists . Diagnosis is often difficult , as the entity is frequently associated with other mental disorders . Differential diagnosis should consider malingering if the individual 's principal concern is with financial or forensic gain or with the avoidance of obligations ; and factitious disorder , if the individual 's principal concern is with assuming a patient role .   It is generally believed that DID rarely resolves spontaneously . In general , the prognosis is poor , especially for those with comorbid disorders . There is little systematic data on rates of the condition . It is believed to affect between 1 % and 3 % of the general population , and between 1 % and 5 % in inpatient groups in Europe and North America . DID is diagnosed more frequently in North America than in the rest of the world , and is diagnosed three to nine times more often in females than in males . Rates of diagnoses increased greatly in the latter half of the 20th century , along with the number of identities ( often referred to as `` alters '' ) claimed by people ( increasing from an average of two or three to approximately 16 ) .   DID is also controversial within the legal system , where it has been used as a rarely successful form of the insanity defense . The 1990s showed a parallel increase in the number of court cases involving the diagnosis . DID became a popular diagnosis in the 1970s , '80s , and '90s , but it is unclear whether the actual rate of the disorder increased , whether it was more recognized by health care providers , or whether sociocultural factors caused an increase in therapy-induced ( iatrogenic ) presentations . The unusual number of diagnoses after 1980 , clustered around a small number of clinicians , and the suggestibility characteristic of those with DID , support the hypothesis that DID is therapist-induced . The unusual clustering of diagnoses has also been explained as due to a lack of awareness and training among clinicians to recognize cases of DID .