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Why Are Mental Illness and Substance Abuse Linked So Often?

By Zawn Villines
Medically Reviewed by Yilang Tang, MD, PhD on July 26, 2021
Mental illness and substance abuse often go hand-in-hand. Here’s what you need to know about the link between mental health and addiction.

According to the National Institute on Drug Abuse, in 2018, 37.9% of people with a substance use disorder also had a mental illness. Among people with a mental illness, 18.2% also had an addiction. Mental illness and substance abuse often occur at the same time. Doctors call this a comorbidity or dual diagnosis. Treatment for co-occurring disorders must focus on treating both mental illness and substance abuse, rather than assuming treatment for one will cure the other. 

Mental Illness and Drug Abuse 

“One of the primary reasons mental illness and substance abuse often co-occur is because alcohol and drugs serve as a great short-term coping mechanism for various mental health issues such as anxiety and depression, bringing about rapid relief and pleasure,” Aaron Sternlicht, LMHC, CASAC, an addiction specialist at Aaron and Lin Coaching, tells WebMD Connect to Care. 

Self-medication, which is when you use drugs to mask mental health problems, does not cure the underlying mental illness. A 2018 study published in Depression and Anxiety identified several risk factors for self-medication in people with mood disorders such as depression. These include: 

  • Being caucasian 
  • Being male 
  • Being divorced, widowed, or separated 

A 2018 study published inAddictive Behaviors also links shame to substance abuse and mental illness. Specifically, the study found a link between shame and addictive behaviors like excessive drinking and gambling addiction. It also found that people with depression have higher baseline levels of shame, which increases their risk of addiction. Over time, self-medication may make mental illness worse or create new mental health issues. 

“Mental health issues such as anxiety and depression can be substance-induced, meaning that the mental health issue is caused by substance abuse. This is even true of more pervasive mental health symptoms such as mania, paranoia, and auditory or visual hallucinations that can mimic mental health disorders such as bipolar disorder or schizophrenia,” Sternlicht says. 

While mental illness can lead to addiction and addiction can lead to mental illness, the National Institute on Drug Abuse cautions that having a dual diagnosis doesn’t necessarily mean one condition caused the other. It can be challenging to determine which came first. There is also a third possibility: Some common factors (such as genetics) may contribute to both mental illness and addiction. 

Don’t Wait. Get Help Now. 

According to the National Institute on Drug Abuse, 52.5% of people with co-occurring disorders receive no treatment at all, and just 9.1% receive treatment for both conditions. This greatly increases the risk of relapse and chronic mental health problems. 

If you or a loved one are struggling with addiction, WebMD Connect to Care Advisors are standing by to help. 

Treatment & Resources: General Information