Multiple Personalities, now known as Dissociative Identity Disorder (DID), is the single most controversial diagnosis in the diagnostic manual. Most would agree with that statement I think.
One of the most bizarre aspects of this diagnosis and its promoters is the wish to have their cake and eat it too. Let me give you a few examples of what I am talking about. These are composite examples that have been slightly altered, not pertaining to any individual patient, but the comments attributed to therapists essentially express comments I have heard at one point or another.
Patient A signed a legal contract and later wanted to back out. Patient A's therapist states, without any sign of misgiving or embarrassment: "People just don't understand that [Patient A]'s part [alternate personality] signed the contract and [Patient A] can't be held responsible." Why is this having and eating cake simultaneously? Well, let me explain. Both the patient and the therapist believe and strongly advocate for Patient A's right to live and act in the community as a fully fledged adult citizen, and yet, they both want the world hold Patient A free of all agreements and obligations that Patient A has selectively decided some other personality inhabiting her body is responsible for. This sort of undermines the basic social contract doesn't it? Either Patient A is mentally competent to make agreements and sign contracts and be held responsible for her obligations, or if she really cannot competently sign contracts and be held responsible due to her psychiatric condition she should not be allowed to and her her therapist needs to be working to develop a legal guardian who can actually make binding decisions on behalf of Patient A who is apparently not competent to do so on her own.
Patient B is granted Social Security Disability for a psychiatric condition. His primary diagnosis is DID. He then enters university and goes through to complete a graduate program. Throughout, he continues to receive monthly disability payments intended for individuals who are too disabled to work. Both he and his therapist maintain that Patient B is both entitled to disability and able to legitimately complete a graduate program in the field of economics because his parts switch only when he is at the school and he can temporarily maintain his "host personality." When returning home or out in the community he "switches" to different personalities and is therefore disabled. After receiving his degree in economics, he continues to receive monthly disability payments and his therapist continues to be paid by Medicaid. Patient B is both disabled and yet he is not. It seems to me an ethical and competent therapist would be working with Patient B to utilize his graduate degree in a productive manner to his own personal and financial benefit. Instead, the therapist continues to promote the idea that in spite of earning a graduate degree Patient B is too disabled to work and must continue in therapy indefinitely. It may be no coincidence that if Patient B earns wage income, he will ultimately lose both Social Security Disability and Medicaid and the therapist's cash cow with dry up.
Patient C commits a felony crime of posing as a property owner (which she is not), collecting deposits and rents from multiple prospective renters and then flees the scene. She spends the money on a car, clothing and a purebred Pomeranian dog for herself. When tracked down by detectives and arrested, Patient C, her therapist and her defense lawyer all maintain that Patient C cannot be held responsible for the crime. None of them dispute that her physical body was present at the time of the crime and in fact committed the crime, but they claim her body was inhabited by a personality who believed it was the property owner, therefore person/body of Patient C (the only legal and biological entity in this case) cannot be held responsible. The "host personality" of Patient C cannot be held responsible because she was dissociated and was not aware of what occurred and had no control over it. Furthermore, the "property owner" personality cannot be held responsible either because he/she/it really believed it was a property owner and did not realize it was committing a crime. What does the therapist and defense attorney request? That Patient C be freed and allowed to continue the same therapy (that failed to prevent her criminal behavior in the first place) because this is what Patient C "needs."
DID patients, therapists and promoters seem to have a problem with responsibility. Basically they can disavow responsibility for anything with negative consequences for the patient/client/consumer but otherwise expect the world to treat the DID patient as a completely competent and responsible citizen. Does that sound just a little too convenient? Most jurors find it pretty fishy, that's why it almost never succeeds as a legal defense, but that doesn't stop people from trying.
Here are some interesting facts about DID and crime. A small study published in 1989 (Putnum, Diagnosis and treatment of multiple personality disorder) found that 35% of female DID patients reported committing crimes including 7% of which were homicides and 47% of men with DID reported committing crimes of which 19% had committed homicide.
In the end, you can't have your cake and eat it too.