Can Drugs Cause Mental Illness?

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Can drugs cause mental illness?

It is well-established that substance abuse and addiction can contribute to the development of mental health disorders. Research suggests that drug use can lead to changes in some of the same areas of the brain that are affected by mental illnesses, such as mood disorders, anxiety disorders, impulse-control disorders, and schizophrenia.

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Additionally, people who struggle with addiction may experience other negative consequences that can further contribute to the development of mental health disorders. These can include social isolation, financial difficulties, relationship problems, and legal issues, among others.

In cases where a mental health condition occurs simultaneously as substance abuse disorder (addiction), most addiction treatment programs will issue a dual-diagnosis diagnosis. This way, the mental health issue can be treated alongside the addiction to help shut down any correlations that may be exacerbating both issues.

Mental Health and Drugs

Drug use and addiction can be influenced by mental illnesses, as certain mental disorders are considered risk factors for developing a substance use disorder. This can happen when individuals with mild or severe mental health problems resort to using drugs as a form of self-medication. That said, although some drugs may provide temporary relief from mental health symptoms, they can also worsen them in the long run. Cocaine, for instance, may worsen the symptoms of bipolar disorder and contribute to its progression.

Changes in brain activity associated with mental illnesses can also increase vulnerability to substance abuse by enhancing the rewarding effects of drugs, reducing awareness of their negative effects, or alleviating the unpleasant symptoms of the mental disorder or medication side effects. For example, neuroimaging research has shown that ADHD (attention deficit hyperactivity disorder) is linked to neurobiological changes in brain circuits that are associated with drug cravings. This may explain why individuals with comorbid ADHD and substance use disorders report greater cravings.

In some cases, drug use that occurs prior to the onset of a mental illness can produce changes in brain structure and function that may exacerbate underlying vulnerabilities and predispositions to mental health disorders. This is particularly true for those who may have a family history of mental illness or a genetic predisposition to developing one.

The changes in brain activity and structure that can occur as a result of substance abuse can lead to a host of mental health issues. For example, chronic use of certain drugs can produce long-lasting changes in brain function that are linked to depression and anxiety, while cocaine use can cause symptoms of paranoia and psychosis.

Is Substance Abuse a Mental Illness?

While the question, “Can drugs cause mental illness?” is a common one for those in addiction recovery, the connection between drug addiction and mental illness is complex and not always clear with substance abuse. Mental illness is not as simple as determining which one came first, as many factors come into play. Sometimes, behavioral or emotional issues may not be severe enough for a diagnosis, but they may still contribute to drug use. Additionally, some people may have difficulty recalling the timeline of events, making it challenging to establish the connections between substance abuse and mental health issues.

So, can drugs cause mental illness?

A woman watching the sunset, wondering if drugs cause mental illness

Substance Abuse and Mental Health

Mental illness and substance use are closely linked, with substance use disorders (drug addictions) and mental illnesses often co-occurring. The relationship between mental illness and addiction is complex and multifaceted, with each condition potentially inflaming the other.

Substance use disorders may contribute to the development of mental illness, while pre-existing mental health conditions can increase the risk of substance abuse. For individuals who experience both substance use disorders and mental illness, integrated treatment is essential to address both conditions and improve overall health and well-being.

In this guide, we will explore the relationship between substance abuse and mental health, the ways in which each can contribute to the other, and effective treatments for co-occurring disorders. We also address these issues:

  • How does addiction affect mental health?
  • Do drugs cause mental illness?
  • What is the correlation between dual diagnosis, mental health, and substance abuse?
  • What is the most common mental illness caused by drugs?

Addiction and Mental Health Statistics

These drug and mental health statistics illustrate the growing problem of substance abuse and mental health disorders in the United States. 

According to data from NSDUH 2021, 1.1 million American adults reported using heroin, with a staggering 91% of past-year users developing a diagnosable heroin addiction. 

Similarly, 8.7 million adults reported using prescription painkillers, and 78% of past-year users developed a prescription painkiller addiction.

  • Meth use affected 2.5 million adults, with 64% of past-year users developing a meth addiction.
  • Opioid use was reported by 9.2 million adults, and 58% of past-year users developed an opioid addiction.
  • For benzodiazepines, 3.9 million adults reported use, and 51% of past-year users developed an addiction to this drug.
  • Prescription stimulant use was reported by 3.7 million adults, with 32% of past-year users developing an addiction.
  • Cocaine use was reported by 4.8 million adults, with 29% of past-year users developing a cocaine addiction.
  • The most commonly used drug, marijuana, was reported by 52.4 million adults, with 29% of past-year users developing a marijuana addiction.
  • Alcohol use was reported by 213 million adults, and 14% of past-year users developed an alcohol addiction.
  • Finally, 2.2 million adults reported using inhalants, and 11% of past-year users developed an inhalants addiction. Among those who used hallucinogens like PCP, Ecstasy, and LSD, 445,000 developed a diagnosable addiction, which represents 6% of past-year users.

These statistics highlight the need for effective substance abuse prevention and treatment programs to help individuals struggling with addiction.

In the United States, mental illness affects millions of people annually, with significant impacts on their physical, social, and financial well-being. By measuring the prevalence of mental illness, we can better understand its scope and impact, raise public awareness, reduce stigma, and advocate for improved healthcare.

Here are some fast facts about mental illness in the U.S. from NAMI (National Alliance on Mental Illness):

  • Approximately one in five U.S. adults report mental illness each year.
  • About one in 20 U.S. adults report serious mental illness each year.
  • Around one in six U.S. youths aged 6-17 report a mental health disorder each year.
  • Half of all lifetime mental illness begins before age 14, and three-quarters before age 24.
  • Suicide is the second leading cause of death among people aged 10-14.

These statistics illuminate the urgent need for mental health support and resources in the United States, especially for young adults. By understanding the prevalence and impact of mental illness, we can work to create a more compassionate and effective mental health care system.

Co-occurring Substance Abuse and Mental Disorders Statistics

Co-occurring mental health and substance use disorders are known as co-occurring disorders or dual diagnosis.

Data from SAMHSA (Substance Abuse and Mental Health Services Administration) indicate that 17 million U.S. adults reported a dual diagnosis involving an addiction and any mental illness in 2020. This represents a significant increase from 9.7 million U.S. over-18s with a dual diagnosis in 2019. In the same year, 5.7 million U.S. adults reported a dual diagnosis involving an addiction and a serious mental illness

What is the relationship between substance use and mental illness, then?

Relationship Between Addiction and Mental Illnesses

The comorbidity between substance abuse and mental illness can stem from three main directions:

  1. Common risk factors can contribute to both mental illness and substance use and addiction.
  2. Mental illness may contribute to substance use and addiction.
  3. Substance use and addiction can contribute to the development of mental illness.

Firstly, both substance abuse and mental illness can be caused by common risk factors that include genetics, environmental factors, and issues with similar areas of the brain. Research indicates that 40-60% of a person’s vulnerability to substance use disorders is attributed to genetics, and the search is on for genes that predispose individuals to develop both a substance use disorder and other mental illnesses.

In addition to genetic factors, environmental influences such as early exposure to stress or trauma can contribute to the comorbidity between mental health and drug addiction. Childhood adversity, including neglect, abuse, and household dysfunction, has been linked to an increased risk of substance use and mental health disorders. Other environmental factors like social and economic circumstances, peer pressure, and availability of drugs can also play a role in the development of dual diagnosis.

Is Drug Addiction a Mental Illness?

Drug addiction, also known as substance use disorder, is considered a mental illness. It is recognized as a chronic and relapsing brain condition characterized by the compulsive use of drugs regardless of the harmful consequences.

Like other mental illnesses, addiction mental disorder involves changes in the brain’s reward, motivation, and learning circuits. Chronic drug use can lead to structural and functional changes in the brain, such as a decrease in the number of dopamine receptors, which can alter the way the brain responds to natural rewards and increase the craving for drugs. This can make it difficult for individuals with substance use disorder to quit on their own, even if they are aware of the harmful consequences.

It is worth noting that not everyone who uses drugs will develop an addiction. That said, certain factors such as genetics, trauma, stress, and environment can increase the risk of developing a substance use disorder. Additionally, some drugs have a higher potential for addiction due to their pharmacological properties and the way they affect the brain.

Recognizing drug addiction as a mental illness is essential for effective treatment. It allows for a more comprehensive approach that addresses not only the physical symptoms of addiction but also the underlying psychological and emotional factors.

Treatment for Co-occurring Disorders

When someone is struggling with both a substance use disorder mental health condition, it is essential that they receive treatment for both conditions simultaneously. Treatment for co-occurring disorders, also known as dual diagnosis, integrates interventions for both disorders into a comprehensive treatment plan that is tailored to each individual’s unique needs. The ultimate goal of this type of treatment is to help individuals achieve and maintain sobriety while also effectively managing their mental health symptoms.

Effective treatment for co-occurring disorders typically involves a combination of therapies, including medication-assisted treatment, behavioral therapies, and support groups. Medications can be prescribed to manage symptoms of mental illness, such as depression or anxiety, while also helping to reduce cravings for drugs or alcohol. Behavioral therapies, such as CBT (cognitive-behavioral therapy) and DBT (dialectical behavior therapy), can help individuals develop coping skills and strategies to manage both their substance use and mental health symptoms.

In addition to medication and therapy, support groups such as AA (Alcoholics Anonymous) or NA (Narcotics Anonymous) can provide a valuable source of ongoing support and encouragement for individuals in recovery from co-occurring disorders. These groups offer a sense of community and a safe space to share experiences and struggles with others who are facing similar challenges.

Overall, treating co-occurring disorders requires a holistic and integrated approach that addresses both substance use and mental health issues concurrently, as well as the mental problems caused by drugs. Treatments can include therapies like Cognitive Behavioral Therapy (CBT), Medication-Assisted Treatment (MAT), and sober group meetings in Long Beach and alumni programs for continued care.

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Get Help For Substance Abuse and Mental Illness at California Detox

If you suspect you may have a dual diagnosis involving mental health and drug issues, it’s vital to address this issue and seek support from reputable inpatient treatment centers that specialize in dual-diagnosis care.

At California Detox, we understand the importance of receiving appropriate care to achieve and maintain sobriety, particularly if you’re dealing with a co-occurring mental health condition. Our comprehensive dual diagnosis treatment programs provide continuous clinical and emotional support from detox through to discharge.

Managing a dual diagnosis can be challenging, but it’s encouraging to know that help is available, and that many people have successfully maintained their sobriety while dealing with co-occurring conditions. Contact California Detox today at 949.694.8305 to take the first step towards recovery.


Substance abuse can contribute to the development of various mental illnesses, including schizophrenia, anxiety disorders, mood disorders, and impulse-control disorders due to changes in brain areas that are disrupted in these conditions.
The three main types of substance-related disorders are substance use disorders, substance-induced disorders, and substance-induced mental disorders. Substance use disorders involve a pattern of using a substance that leads to significant impairment or distress, substance-induced disorders are caused by the direct effects of a substance, and substance-induced mental disorders involve the development of a mental disorder as a result of substance use.


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