Multiple Personality Disorder Symptoms

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Dissociative identity disorder or multiple personality disorder symptoms are very similar to those of other types of mental illnesses, making diagnosis difficult. But the characteristic symptom is containing two or more distinct personalities in the same body.

Multiple Personality Disorder Symptoms: Physical

People with multiple personality disorder often suffer from chronic physical pains such as severe headaches or even seizure disorders. The National Alliance on Mental Illness reports that one third of all patients hear sounds no one else can, including voices. Auditory hallucinations are also found with people suffering from migraine aura or tinnitus. The presence of persistent physical symptoms may impede a proper diagnosis of having any sort of mental illness or even having another mental illness such as bipolar disorder.

Cutting oneself with sharp objects is common among people suffering from multiple personality disorder but not every patient will mutilate themselves. Another common physical symptom is a chemical dependence on drugs or alcohol even to the point of addiction.

Multiple Personality Disorder Symptoms: Psychological

Physiological symptoms and their severity will differ from patient to patient, but generally they are:

  • Deep depression
  • Mood swings
  • Amnesia
  • Can one day accomplish complex tasks, but during the next day are unable to perform the simplest tasks
  • A persistent feeling of unreality, as if they are watching another person’s life rather than living their own

The Alters

The altered personalities of multiple personality disorder are not to be confused with the play-acting of children when they may insist that they are someone else. Alters are so distinct from the original personality that they can be left-handed when the person is right-handed or vice versa. Some alters may have physical problems such as nearsightedness that the main personality does not. Patients with dissociative identity disorder may have only one alter or they may have 100.

The theory is that alters perform specific functions that the main personality cannot handle. Unfortunately, some alters can become quite detrimental to the main personality. They may go on a spending spree or even commit crimes. One patient diagnosed with multiple personality disorder was William Stanley Milligan. In 1977, he was arrested for three rapes in Ohio. The court was presented with an interesting legal problem – should Milligan be punished for a crime his alters committed? He was found not guilty by reason of insanity.


Milligan’s case, still considered controversial, should be considered highly unusual among people with multiple personality disorder. Normally, patients are more of a danger to themselves than to the surrounding public. Not all alters can be immediately identified from the core personality. Because multiple personality disorder symptoms are similar to other illnesses, patients can be difficult to diagnose and may have already gone through two or three other diagnoses before a doctor or therapist forms a correct opinion.


National Alliance on Mental Illness. “Dissociative Identity Disorder (Formerly Multiple Personality Disorder.)”

Merck Online Manual. “Dissociative Identity Disorder.”

Radden, Jennifer. “Am I My Alter’s Keeper? Multiple Personality Disorder and Responsibility.” Southern California Interdisciplinary Law Journal. Vol 10:2.