In one sense, asking about the connection between drug addiction and mental illness is like asking what is the connection between cancer and physical illness: one is a subset of the other. However, in the popular mind, alcoholism and drug addiction are viewed as strange beasts somehow outside of the category of mental illness. Addiction has long been seen as a moral failing, a matter of choice, and an issue of lack of discipline.
According to the National Institute on Drug Abuse, drug addiction qualifies as a mental illness because “addiction changes the brain in fundamental ways, changing the person’s normal hierarchy of needs and desires and substituting of new priorities connected with procuring and using the drug.”
As a consequence, compulsive behaviors dominate the addict and actions are taken and repeated without appropriate regard for consequences. Additionally, the DSM (Diagnostic and Statistical Manual of Mental Disorders)—the American Psychiatric Association’s standard resource for classifying mental disorders—establishes criteria for drug use disorders, citing two types: drug abuse and drug dependence.
So, drug addiction itself qualifies as a mental illness, but there are further complications. According to the National Alliance on Mental Illness, nearly one-third of those with mental illnesses also have substance-abuse problems. This figure increases to fifty percent when the underlying mental illness is severe, as in bipolar disorder or schizophrenia). Additionally, a study of alcoholics and drug abusers indicated comorbidity (alcoholism/drug addiction plus another mental illness) in one third and one half, respectively, of the subjects.
A complicating factor in diagnosis and in understanding the dynamics of an individual’s addiction to alcohol and drugs is that whereas many substance abusers begin—and continue—their experimenting because it’s “fun,” and cross a line into dependency because of repetition, others are in fact self-medicating and underlying pre-existing mental illness. Anxiety and depression are often masked by substance abuse: the user alleviates the symptoms of the underlying problem but develops a further problem with the substance being used, ultimately aggravating the underlying condition. When the substance is removed, the original anxiety or depression leaves the sufferer in need of treatment above and beyond that needed for the drug or alcohol problem.
Drug addiction and mental illness are a tangled knot for the patient as well as for the treatment provider, but expertise and advanced medical technology are available that can provide a blueprint for a healthy and productive life.