Substance abuse and mental illness are closely related and tied together. Drugs and alcohol directly impact various parts of the brain that also play roles in overall mental health. Physicians refer to the presence of both a mental illness and a substance use disorder as “dual diagnosis.”

44.6 million people in the United States live with some type of mental illness, according to the 2016 National Survey on Drug Use and Health. Of those people, 8.2 million also struggle with a substance use disorder. An additional 10.8 million people have a substance use disorder but no mental illness.

Some of those 8.2 million people had a mental illness to begin with and started using drugs to cope with it. Others who had no history of mental illness used so many drugs that they developed one as a result.

How can substance abuse lead to mental health issues? What happens after a mental illness develops as a result of someone’s drug use? Continue reading to understand the relationships between substance use and mental health.

Substance use disorder graph

The Relationship Between Mental Illness and Substance Abuse

Put simply, drugs affect the pathways of communication in the brain. They interact with various receptors responsible for providing feelings of pleasure, relaxation, or excitement. If someone uses a lot of drugs regularly for a long period of time, they functions in their brain start changing.

Some of the common and unpleasant side effects of drug use may settle in instead of disappearing after a while. When these effects don’t lessen after time, the person might develop a short-term or long-term mental illness. This often leads to in an increase in substance use to counteract the uncomfortable effects of mental health problems.

Again, the presence of both mental illness and a substance use disorder at the same time is called dual diagnosis. People with dual diagnosis conditions have two separate but related problems to look at. They usually use drugs to relieve the side effects of their mental illness but the side effects of their condition worsen as a result drug use.

This vicious cycle continues until someone receives help for their conditions. This is one of the dozens of reasons people should never start using drugs. With the possible development of a mental illness as a side effect, why would anyone even start?

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Dual diagnosis, or co-occurring disorders, is a difficult and complicated condition to both live with and treat. Find out everything you want to know!

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Drugs that Can Cause Mental Illness

The National Institute on Drug Abuse compiled a list of drugs that can cause mental illness.


Cocaine is a popular party drug, often used in combination with alcohol during a night out. Heavy cocaine use causes massive, short-term dopamine spikes that lead to overwhelming lows. Depression may result from excessive cocaine use and the repeated depletion of dopamine levels.


Inhalant abuse refers to the concentrating and inhaling of chemicals in aerosol sprays or solvents. Inhalants are incredibly toxic substances containing any number of different chemicals. This essential poisoning of the brain and body may result in neurological conditions that affect cognition, memory, motor skills, and more.


Ketamine is another popular party drug that causes euphoria and dissociation. Excessive use of ketamine might result in a short- or long-term dissociative state or depression.


LSD is a powerful hallucinogenic drug that causes people to hallucinate for periods of up to 12 hours. LSD has the potential to be an incredibly dangerous drug when it comes to someone’s psychological state. The effects vary depending on how mentally sound someone is when taking it and how well they handle the essential psychosis they enter. Some people come out of their trips with a lasting sense of paranoia, anxiety, and extreme fear.

MDMA (Ecstasy)

MDMA (also called ecstasy) is another club drug used in party settings. It is popular for its enhancing effects on the senses as well creating feelings of euphoria and well-being. Similar to cocaine, though, MDMA causes large buildups of dopamine in a short period of time. This causes dopamine depletion that leads to a “down in the dumps” feeling afterwards. Excessive MDMA use may cause lasting depression in some people.

Methamphetamine and Prescription Stimulants

Methamphetamine and prescription stimulants (such as Adderall, Ritalin, Concerta) are similar drugs. They contain the same active ingredient amphetamine that causes bursts of energy and euphoria. Excessive methamphetamine use may land users in a psychosis that persists for days or weeks at a time. Some people end up with lasting effects from these psychoses that result in mental illness.

Seeking Dual Diagnosis Treatment

Both mental illness and substance abuse are still widely misunderstood, even in today’s times. People still believe they are conditions that a person has control over, that someone can just “quit using” or “snap out of it.” This lack of understanding makes it difficult for people to openly speak about the things they deal with daily.

Former Client is talking about the program at Hawaii Island Recovery

John Burke about addiction treatment at Hawaii Island Recovery

When someone struggles with both mental illness and substance abuse, their problems are multiplied. Their vicious cycle of worsening symptoms and increased drug use creates a problem best handled by an addiction treatment center. Some facilities, such as Hawaii Island Recovery, are specially equipped to work with dual diagnosis individuals.

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