Mental Health and Substance Use: Understanding Dual Diagnosis and Treatment

Mental Health and Substance Use Are More Connected Than You Think 

By Anne Donnelly, Community Engagement Team  

At SouthLight, about 80% of clients have a “dual diagnosis,” meaning they’re experiencing both mental health and substance use disorders. As SouthLight’s Chief Medical Officer Dr. Letitia Hazel explains, the line between coping and crisis is often thinner than we think. 

“Sometimes substance use is used as a way to cope with an undiagnosed mental health issue. For example, some people may choose to drink alcohol to deal with feelings of anxiety. This could look like having a glass of wine to unwind at the end of the day. However, if the use escalates, it can lead to dependence and other unintended consequences.”

Amy L. Brundle of the National Alliance on Mental Illness, North Carolina (NAMI), points out that dual diagnosis is captured in national data as well. “The number of American adults living with a mental health condition is growing close to 25%. That’s why awareness and access to care are so important.” 

Mental Health vs. Substance Use: Which Comes First? 

The relationship between mental health conditions and substance abuse disorders is complex. Determining which came first can have you chasing your tail. “It’s a chicken and egg situation,” says Brundle. “There aren’t easy answers to these questions.” 

“Sometimes things like depression, anxiety, or trauma can lead to substance use,” says Dr. Hazel. “The person doesn’t want to feel the pain. They may want to forget a traumatic experience. When they discover a substance that they feel “makes it all go away” it may be hard for them to stop using it.” 

Other times, the abused substance alters brain function, impacting mental health. Dr. Hazel uses the example of a college student trying marijuana. It could be laced with another substance, like methamphetamine which could trigger a mental health episode.

In addition, guilt and shame about substance use can inflame depression and anxiety, decreasing self-worth. Dr. Hazel says the resulting judgmental monologue of ‘I need to fix it; I should be better’ actually makes people more vulnerable to relapse. “It’s that slippery, slippery slope down.”  

Why Understanding the Mental Health and Substance Use Connection Matters 

By renewing our focus on the mental health and substance use connection, we can better appreciate how they interact with each other, have greater empathy for our loved ones struggling with these issues, and be effective helpers on their treatment journey.  

Education and awareness efforts have brought us far, but mental health and substance use continue to be bogged down by the same stigma. “One of the biggest fallacies is that there is something inherently wrong with the person. That their substance use is a “moral failing” and the person can stop whenever they want to. That’s just not true. When the brain is exposed to certain substances, the brain chemistry can become altered. The part of the brain that controls reasoning and judgment, gets hijacked. The person is no longer in control. The substance has taken over.” says Dr. Hazel.  

Brundle adds that, “People can’t will themselves out of mental health disorders or substance use disorders. It takes intervention and treatment.”  

How Caregivers Can Support Loved Ones with Mental Health and Substance Use Disorders 

Dr. Hazel urges the caregivers of those dealing with substance abuse and mental health to remember that the two are connected and to cultivate empathy however they can, for their loved one and for themselves.  

“Where do you find the soft spot for someone who’s hurting?” Dr. Hazel asks. “We don’t look at a kid who’s skinned their knee and go, ‘You shouldn’t have fallen off that bike.’ We say, ‘Oh, that does hurt.’ We lean into the empathy of it.” 

Brundle cautions that vilifying people for a “lack of discipline” contributes to the stigmas we fight as mental health providers, preventing people from seeking treatment and prioritizing recovery.  

Dr. Hazel acknowledges that caregivers are hurting too. They might have experienced difficult behavior from their loved ones undergoing substance abuse and mental health issues. Or they’re grieving the dream life they envisioned for their loved one. Seeking treatment for yourself can be valuable.  

Recovery Takes Time: Treating Mental Health and Substance Use Together 

If you’re supporting someone through mental health or substance use challenges, you’re not alone—and neither are they. 

Healing and recovery take time, and it often requires more than willpower. It requires connection, compassion, and care that treats the whole person. 

“The thing I love about SouthLight is the combination of our compassion and expertise. We understand the complexities of mental health and substance use, especially when they are co-occurring. Our organization is unique in that we have the capacity and expertise to treat both at the same time.” 

If you or someone you love needs help, call SouthLight. Visit our resources page or start with our blog on how to talk to someone who is struggling.