Understanding Dual Diagnosis: Mental Illness and Substance Abuse

Dual diagnosis, also known as co-occurring disorders, is a term used to describe a situation in which a person has both a mental health problem and a substance use disorder. It is estimated that around half of people with a mental disorder will also have a substance use disorder at some point in their lives, and vice versa. The interaction of the two conditions can worsen both, making it difficult to diagnose and treat. People with mental illness may resort to substances in an attempt to self-medicate, while those who experiment with or misuse substances can worsen underlying mental illnesses.

Substance use can even change the brain in ways that increase the risk of developing mental illness. People with dual diagnosis have complex needs related to health, social, economic and emotional stressors or circumstances that can often be exacerbated by their substance abuse. Mental health professionals should diagnose and treat individuals with dual diagnosis appropriately and conveniently due to the potentially serious consequences associated with this disorder. While there is no standard dual-diagnostic intervention, mental health professionals can use best practices to individualize their treatment.

Poor communication, poor information exchange, inflexible appointment times, and too strict entry criteria present obstacles for dual-diagnostic service users. In 2002, the Department of Health commissioned the Research Unit of the Royal College of Psychiatrists to develop an information manual for professionals working in the field of dual diagnosis. This manual is designed to help professionals plan, organize and provide services to people with dual diagnosis. Treatment for dual diagnosis may include helping families and caregivers adjust the support and expectations of the person with a dual diagnosis. It is not always possible to match the symptoms or behaviors of a dual-diagnosed person with a specific psychiatric disorder.

In Victoria, as in other parts of the world, mental health services and alcohol and other drugs are working with an increasing number of people with dual diagnosis. Research is needed to identify effective treatment approaches for other dual-diagnosed subgroups of the population, such as military personnel. A substance use disorder is diagnosed when a person is unable to control their use of alcohol or legal or illegal drugs. Because one disorder may mask or intensify the symptoms of the other, it is often difficult to determine which one occurred first and may make it more difficult to diagnose.