Dual Diagnosis: Substance Abuse and Mental Illness

Dual diagnosis is a term used to describe people with mental illness who have coexisting problems with drugs and/or alcohol. The relationship between the two is complex, and the treatment of people with co-occurring substance abuse (or substance dependence) and mental illness is more complicated than the treatment of either condition alone. This is unfortunately a common situation—many people with mental illness have ongoing substance abuse problems, and many people who abuse drugs and alcohol also experience mental illness.

Certain groups of people with mental illness (e.g., males, individuals of lower socioeconomic status, military veterans and people with more general medical illnesses) are at increased risk of abusing drugs such as marijuana, opiates, cocaine and other stimulants, and alcohol. Recent scientific studies have suggested that nearly one-third of people with all mental illnesses and approximately one-half of people with severe mental illnesses (including bipolar disorder and schizophrenia) also experience substance abuse. Conversely, more than one-third of all alcohol abusers and more than one-half of all drug abusers are also battling mental illness.

What is the relationship between substance use and mental illness?

The relationship between mental illness and substance abuse or dependency is complex. These relationships are often considered in the following ways:

  • Drugs and alcohol can be a form of self-medication. In such cases, people with mental illness may have untreated—or incompletely treated—conditions (such as anxiety or depression) that may “feel less painful” when the person is high on drugs or alcohol. Unfortunately, while drugs and alcohol may feel good in the moment, abuse of these substances doesn’t treat the underlying condition and—almost without exception—makes it worse.
  • Drugs and alcohol can worsen underlying mental illnesses. This can happen both during acute intoxication (e.g., a person with depression becomes suicidal in the context of drinking alcohol) and during withdrawal from a substance (e.g., a person with panic attacks experiences worsening symptoms during heroin withdrawal).
  • Drugs and alcohol can cause a person without mental illness to experience the onset of symptoms for the first time. For example, a twenty-year old college student who begins to hear threatening voices inside of his head and becomes paranoid that his chemistry professor is poisoning his food after smoking marijuana could represent a reaction to the drug (potentially called a “substance-induced psychosis”) or the first episode of psychosis for this individual.

Abuse of drugs and alcohol always results in a worse prognosis for a person with mental illness. People who are actively using are less likely to follow through with the treatment plans they created with their treaters: they are less likely to adhere to their medication regimens and more likely to miss appointments which leads to more psychiatric hospitalizations and other adverse outcomes. Active users are also less likely to receive adequate medical care for similar reasons and are more likely to experience severe medical complications and early death. People with mental illness who abuse substances are also at increased risk of impulsive and potentially violent acts. Perhaps most concerning is that people who abuse drugs and alcohol are more likely to both attempt suicide and to die from their suicide attempts.

Individuals with mental illness and active substance or alcohol abuse are less likely to achieve lasting sobriety. They may be more likely to experience severe complications of their substance abuse, to end up in legal trouble from their substance use and to become physically dependent on their substance of choice.

What treatments are available for individuals with dual diagnosis?

Treatment of individuals with mental illness and substance abuse is complicated as previously discussed. Of primary importance is addressing any life-threatening complications of intoxication. The following situations would require immediate medical care in the hospital setting:

  • Severe cases of alcohol intoxication may require emergent medical treatment and can result in death.
  • Use of amphetamines, crack, cocaine and other drugs can result in heart problems (e.g., arrhythmias, heart attacks), stroke and death.
  • Use of benzodiazapines (e.g., diazepam [valium], clonazepam [klonopin]), opiates (e.g., oxycodone, oxycontin) and other “downers” can result in extreme sedation and potentially death in overdose.

Drug and alcohol withdrawal can lead to medical emergencies requiring immediate treatment. This can occur when a person who has been regularly using a particular substance has become “addicted” (i.e., the body has become physically dependent on the substance) and abruptly stops using. Here are some examples that may require immediate medical care in the hospital setting:

  • Alcohol withdrawal can result in heart problems (e.g., arrhythmias), seizures or delirium tremens (an acute delirious state), all which can be potentially fatal.
  • Benzodiazapine withdrawal can result in tremors (“shakes”), seizures and potentially death.
  • Opiate withdrawal is not thought to be life-threatening in most cases, but it can be a very traumatic and painful experience.

Therefore, many people seek assistance in going through the process of stopping their drug and alcohol abuse. This can include inpatient detoxification which can involve admission to a hospital—either a general hospital or a detoxification facility—and treatment with the appropriate medications to avoid serious complications of acute drug and alcohol withdrawal.

Multiple scientific studies have shown that psychiatric treatments are more effective in people who are not actively abusing drugs and alcohol. Once individuals are safely “detoxed” from drugs or alcohol—or stop abusing drugs that they may not necessarily be “addicted” to—treatment of underlying mental illness may be more successful. This is not to say that people with mental illness cannot be treated while they are still using, rather that treatment of mental illness is generally more effective once one is sober and more able to actively participate in treatment.

Many options exist for people who are newly sober or who are trying to avoid relapse on drugs and alcohol. These can include inpatient rehabilitation centers or supportive housing (e.g., sober houses, group homes or residential treatment facilities). Other people may choose to return home to their friends and family who can be helpful in encouraging newly-sober individuals to continue their efforts. This can be critically important as a significant majority of people will relapse into drug and alcohol abuse at some point in their lives, even if they are eventually able to achieve long-lasting sobriety.

Some people find therapy to be a helpful part of maintaining their sobriety. This can include individual therapy (e.g., cognitive behavioral therapy) as well as self-help groups such as Alcoholics Anonymous, Narcotics Anonymous or Smart Recovery.

Some people may also talk with their doctors about certain medications that can be helpful in maintaining sobriety. The following medication treatments have been safely tested in multiple studies including FDA medication trials. For people with alcoholism, available medications include disulfiram (Antabuse), acamprosate (Campral) and naltrexone (Revia). For people with opiate abuse, available medications include naltrexone (Revia, Vivitrol), methadone and buprenorphine (Subutex, Suboxone). Given how complicated these choices may be, it is necessary for any individual with dual diagnosis and their loved ones to discuss medication management strategies with their doctors.

Families, friends and others can be most helpful in providing empathic and non-judgmental support of their loved one. With this support, the proper medical treatment and effective psychosocial treatments, many people with dual diagnosis will be able to actively participate in their journey to recovery.

Reviewed by Ken Duckworth, M.D., and Jacob L. Freedman, M.D., January 2013

The authors would like to thank Robert Drake, M.D., for contributing to an earlier version of this review.