Woman in depressionAccording to the 2014 National Survey on Drug Use and Health, more than 18 percent of adults in the US who have any type of mental illness also have a substance use disorder.
That amounts to approximately 7.9 million people dealing with these co-occurring disorders. About 2.3 million of people with substance use disorders also have a co-occurring serious mental illness.

These numbers demonstrate that it is very common for mental illness and substance abuse to occur together. In fact, prior or family history of mental health issues is considered to be one of the risk factors for the development of substance use disorders, including addiction. It can also be the other way around; sometimes, substance use can be a risk factor for developing certain mental health issues.

Sometimes, it can be difficult to tell which of the two came first. In many cases, substance abuse develops because of a person self-medicating to manage the symptoms of a mental health disorder; in other cases, the action of a drug on the brain and body can create changes to the nervous and hormone systems that bring on symptoms of a mental health disorder, such as depression or anxiety. Even in the case where the substance abuse comes first and the mental health issue is a result of drug use, it is still necessary for both the substance use disorder and the mental health issue to be addressed together for recovery to be possible.

Addiction and the Brain

As explained in an article by the National Institute on Drug Abuse (NIDA), when a person engages in chronic use of a psychoactive substance – such as alcohol, medications for psychiatric issues, or illicit drugs – the substance can begin to create changes in the brain that alter a person’s perceptions and behaviors. This can often be seen in the behavioral changes exhibited by people who use drugs like nembutal, opiates, or methamphetamine.

Just one example of how this works is the way in which cocaine acts on the brain. According to the Primary Care Companion to the Journal of Clinical Psychiatry, cocaine acts by increasing the availability of dopamine in the brain, creating the stimulant high for which the drug is known; dopamine increases a person’s feeling of wellbeing, alertness, and energy. Over time, continued use of cocaine can cause damage to the dopamine system, making it harder and harder for the person to feel pleasure without using cocaine. This can lead to decreased feelings of happiness and may cause a person to develop anxiety or depressive disorders based on the inability to feel good.

While not all of the pathways in which alcohol and drug use causes these changes are known, it is understood that substance abuse has a variety of effects on the brain that can cause lasting or even permanent damage, resulting in mental and physical health issues.

The Psychological Effects of Addiction

After a certain amount of time, these changes can have a profound effect on the person’s mental health. As an example, a recent study in the Journal of Studies on Alcohol and Drugs, 31 percent of men struggling with an alcohol use disorder had depressive episodes that were specifically caused by alcohol use rather than by independently occurring depression.

According to the Substance Abuse and Mental Health Services Administration’s Treatment Improvement Protocols, mental health disorders that can result from substance abuse include:

  • Delirium
  • Persisting dementia
  • Persisting amnestic disorder (long-term amnesia or memory loss)
  • Psychosis
  • Mood disorders, such as depression
  • Anxiety disorders
  • Perceptual disorders
  • Sexual dysfunction
  • Sleep disorders

Which disorders arise depends greatly on the substance being used. It may also depend on a person’s risk factors for that specific disorder. For example, a person with a family history of depression may be more likely to develop that disorder through the effects of a number of different types of substance abuse.

Drugs and Related Mental Illness

According to the Treatment Improvement Protocols, there is specific potential for certain drugs to contribute to the development of certain mental illnesses, such as:

Alcohol and sedatives: Abuse of these substances, which include benzodiazepine drugs (benzos), can result in depression, anxiety, delirium, and dementia. Short- and long-term memory loss may occur. Especially in the case of alcohol-induced dementia, full recovery may not be possible due to physical brain damage. Withdrawal can result in a protracted withdrawal syndrome that includes perceptual disorders and insomnia.

Cocaine and amphetamines: As described above, symptoms of dysphoria caused by addiction to cocaine can resemble or even reach the levels of depression. Heavy, chronic cocaine use can also result in temporary paranoid psychosis, increases in violent behavior, and anxiety. Long-term issues with memory, concentration, and psychosis may develop.

Opiates: Long-term use of opiates can result in moderate to severe depression, and anxiety is also possible. Withdrawal from opiates can result in lasting anxiety, depression, and insomnia.

Hallucinogens: People who engage in regular use of hallucinogenic drugs can have prolonged psychosis, depression, or anxiety. Flashbacks may also occur as a type of protracted perception disorder.

Marijuana: A study from The Lancet shows that psychotic episodes are a consistent result of long-term marijuana or cannabis use, and evidence points toward marijuana use as a risk factor for the development of psychosis later in life. Marijuana use can also lead to depression and anxiety disorders, though not as consistently.

These are just some of the long-term psychological effects of these substances. Other mental health issues can occur with use of these or other drugs and alcohol.

Challenges of Co-occurring Disorders

When substance abuse and other mental health issues occur together, it can create a challenge for treatment because the co-occurring disorders often have amplifying effects on each other, making it hard to resolve one issue unless the other is also treated.

As an example, people with alcohol use disorders are about 3.7 times more likely to have major depressive disorders, according to an article in Psychiatric Times. The article also states that alcohol prolongs the course of depression, while at the same time, depression that occurs during abstinence from alcohol makes relapse to drinking more likely. Nevertheless, a person who has these co-occurring disorders is likely to drink alcohol to numb the symptoms of depression, prolonging both problems.

In other words, the conditions feed each other. Because of this, treating the alcohol use disorder alone is more likely to result in relapse to drinking if the depression is not treated at the same time.

The Need for Treatment on Both Fronts

This self-perpetuating cycle is present with most co-occurring substance use and mental health disorders, resulting in a need to diagnose and treat the disorders together in order to achieve recovery from all conditions. When all elements of substance use and mental health are taken into account, treatment can be designed to help avoid the downward spiral and decrease the risk of relapse after treatment is completed.

This can be accomplished through using therapy treatments that are shown to be effective in treating both mental health conditions and substance use disorders, such as Cognitive Behavioral Therapy, interpersonal therapy, and mutual support groups. In addition, if necessary, medications that have a low addiction potential are sometimes available to alleviate the mental health symptoms without contributing to further substance abuse. Use of medication in these circumstances should always be approached with caution.

In order to increase the likelihood of a positive treatment outcome, it is important to seek care from a facility that is experienced with cases of dual diagnoses. Personnel trained in identifying multiple disorders perform a thorough analysis of symptoms and determine whether co-occurring disorders are present. They can then design a customized treatment plan to address all aspects of the issues, and adjust the plan over the course of treatment to give the person a higher chance of achieving recovery without relapse to substance use.