The Challenges of Dual Diagnosis

By Hugh C. McBride

Addiction and mental illness share a number of traits: Both are oft-misunderstood disorders that some misguided individuals continue to insist are actually "character flaws" that can be overcome by will power alone; both have biological bases and emotional aspects; and, left untreated, both can ruin lives.

Another similarity is that both conditions often occur in the same person.

Known in medical parlance as a "dual diagnosis," the co-occurrence of mental illness and addiction can present significant challenges to recovering patients as well as to the health care and rehabilitation professionals with whom they are working.

In the "Co-occurring Disorders" section of its website, the nonprofit advocacy group Mental Health America expresses the challenges of dual diagnosis in stark terms:

"For people struggling with co-occurring mental health and substance abuse disorders, physical safety and overall health risks are greater; the impairment of life skills is greater; and the chances for successful treatment are much less - all of which contribute to stigma."

As the National Alliance of Mental Illness (NAMI) puts it, "having a simultaneous mental illness and a substance abuse disorder frequently leads to overall poorer functioning and a greater chance of relapse."


NAMI, which notes that there is little conclusive data on the prevalence of dual diagnosis, cites the following statistics from reports in the Journal of the American Medical Association:

  • About 50 percent of people with severe mental disorders are also affected by substance abuse issues.
  • Twenty-nine percent of all people who are diagnosed with a mental illness also abuse either alcohol or another drug.
  • Thirty-seven percent of alcohol abusers and 53 percent of drug abusers also have at least one serious mental illness.

According to Dr. Andrew Chambers, who led a 2007 study on the brain's role in dual diagnosis, between 20 to 50 percent of all individuals who suffer from anxiety or depression also have some type of addiction, as do 40 to 80 percent of those diagnosed with antisocial personality disorder, bipolar disorder, or schizophrenia. Chambers noted this data in a Dec. 2, 2007 American Psychological Association press release that announced the results of his research.


Though health professionals have long noted the prevalence of dual diagnosis, relatively little research has been conducted into a biological explanation for an individual's predisposition to develop two such potentially debilitating disorders. Many experts believed - and continue to theorize - that addiction follows mental disorders as a result of afflicted individuals attempting to "self-medicate" their psychic pain away.

However, Chambers and his team may have gained some significant insights into the physical roots of this complex condition.

Chambers' research addressed developmental changes in an area of the brain called the amygdala, which is associated with emotions such as fear and anxiety. According to the APA release, his study found that rats whose amygdalas had been surgically damaged during their infancy grew up to be "abnormally under-responsive" to certain stimuli, but were hypersensitive to the effects of cocaine.

In humans, Chambers said in the release, a similar effect could result from brain damage prompted by as-yet-unknown causes. "Early emotional trauma, paired with a certain genetic background, may alter the early development of neural networks intrinsic to the amygdala, resulting in a cascade of brain effects and functional changes that present in adulthood as a dual-diagnosis disorder," he said.

"Brain conditions may alter addiction vulnerability independently of drug history," Chambers added, noting that this may also explain why some dual diagnosis patients do not respond as well as expected to certain psychiatric medications.


According to Dual Recovery Anonymous, a nonprofessional support group based upon the Twelve Step principles of recovery, the following are among the obstacles that can impede the effective treatment of dual-diagnosis patients:

  • The symptoms of a person's mental illness may be masked by the effects of his abuse of alcohol or other drugs.
  • Abuse of - and withdrawal from - alcohol and other drugs can present "false symptoms" that incorrectly suggest the presence of a specific psychiatric disorder.
  • A person's untreated chemical dependency can contribute to a re-occurrence of her mental illness.
  • A person's untreated mental illness can slow his recovery from his addiction, and can cause him to relapse.

Until the mid-1980s, the primary method for dealing with dual-diagnosis patients involved "parallel treatment," in which the two conditions with which the patient was afflicted were treated simultaneously but separately by two distinct health care teams. Over the previous two decades, though, an integrated approach has become the norm, with a unified team addressing all of the patient's needs.

The integrated treatment model has earned widespread approval, with the National Institute on Mental Health advocating that patients "receive consistent treatment, with no division between mental health or substance abuse assistance. The approach, philosophy and recommendations are seamless, and the need to consult with separate teams and programs is eliminated."

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