Co-occurring conditions like drug addiction and multiple personality disorder are surprisingly prevalent in the United States, presenting a unique set of challenges for sufferers and therapists alike. These conditions are generally severe enough independently, but when they co-occur together they often significantly exacerbate each other and can result in disastrous consequences. In some cases the symptoms of MPD can cause a person to use drugs in an effort to seek relief, and in some cases the two conditions are completely unrelated despite the fact that they occur together. In fact, many people develop a substance abuse or alcoholism problem long before a diagnosis of multiple personality disorder is ever made. Understanding the co-occurring nature of drug addiction and MPD is critical to developing effective treatment plans.

Multiple personality disorder is also referred to as Dissociative Identity Disorder and is generally characterized as a lack of connection in a person's thoughts, memories, feelings, actions, or sense of identity, according to an article in WebMD. These dissociations are generally thought to be made in response to some type of severe stress or trauma, whereby the brain makes disconnections between thoughts, feelings and behavior as a protective safety measure. Over time these disconnections can worsen significantly and result in a "split" development of personalities because of the prolonged state of disconnection.

Alcoholism and drug addiction is often developed as a result of dissociative behavior. People may use drugs in response to some type of traumatic experience, to escape or be accepted via social pressure, and to treat symptoms of mental illness or disease. Because drug addiction and multiple personality disorders are so closely related in the way that these conditions are formed, it's not surprising that they often occur together. In fact, drug addiction or alcoholism co-occurs frequently with MPD and other types of mental illness as well, and in many cases there may be three or more co-occurring conditions present in the same individual. According to the Sidran Institute for Traumatic Stress Education and Advocacy;

"Current research shows that DID may affect 1% of the general population and as many as 5-20% of people in psychiatric hospitals. The rates are even higher among sexual-abuse survivors and addicts. These statistics put Dissociative Disorders in the same category as schizophrenia, depression, and anxiety, as one of the four major mental health problems today."

Assuming that these figures are correct and making calculations based upon the 2011 United States Census estimate of 310 million American citizens, this means that more than 3 million people in the country suffer from multiple personality disorder. And based upon estimates of regular drug users in the country, it's possible that 250,000 or more people in the U.S. suffer from both conditions at once.

Treating drug addiction and multiple personality or other mental disorders concurrently is one of the most effective treatment programs available. In general the process of treatment involves detox (during which Acute Withdrawal occurs), inpatient or outpatient treatment and management of Post Acute Withdrawal Syndrome. Therapies utilized in drug addiction treatment apply to mental illness as well and include group, family and individual therapies, as well as biofeedback education and the development and utilization of a foundational support group.