The Intersection Between Substance Use and Mental Illness

For Mental Health Awareness Month, we are sharing insights on substance use, mental illness, and how they connect. If you’re a primary care provider (PCP), we have a section at the end of this article with integrated assessments that can help you screen for substance use and mental illness in patients at your practice.

Before we dive into the data, we have to clarify what we mean when we talk about substance use and mental illness. Mental illnesses, also known as mental health conditions, are disorders that can impact mood, thinking, behavior, and well-being. You’re likely familiar with mental health conditions like anxiety, depression, and bipolar disorder, but there are over 200 kinds of mental illnesses that impact people around the globe.

Substance Use Disorder (SUD), previously known as substance abuse or addiction, is a specific type of mental health condition that involves the problematic use of substances. These substances include alcohol, tobacco, illicit drugs, and prescription medications. 

The Current State of Substance Use & Mental Illness in America

There are 44 million adults in the U.S. with a SUD, and of them, 19.4 million (44%) also have another mental health condition. When it comes to the 14.1 million adults with severe mental illnesses (psychotic/personality disorders, treatment-resistant depression, etc.), 6.4 million (45%) also have a SUD.

Not only are these two conditions often comorbid (i.e., occurring simultaneously), they also have a bi-directional relationship, which means they mutually influence each other.

Here’s one example of this connection:

  • Adults with mental illnesses receive 4% of the total opioid prescriptions distributed in the U.S., but they only represent 16% of our population.
  • Opioid use on its own is associated with higher rates of depression.
  • 22% of people living with chronic pain are prescribed opioids for their symptoms.
  • Those with chronic pain are four times more likely to have depression or anxiety.

Other varieties of SUDs and mental illnesses have similar relationships, and researchers are still seeking clarity on exactly how all these factors intersect.

Why Do Substance Use & Mental Illness Often Occur Together?

50% of people with SUD also have another mental illness, a phenomenon known as “dual diagnosis”. Among them, 37% are dealing with alcohol use, and 53% with drug use. These are truly significant numbers, and there are many reasons why they’re so high. Here’s just a few:

  1. There are common risk factors for the development of SUDs and mental illnesses. These include trauma, early and persistent problem behavior, family conflict/abuse/neglect, issues in school, and low socioeconomic status.
  2. One of the biggest contributing factors to SUDs and mental illnesses is Both SUDs and mental illnesses can run in families, and environmental stresses/traumas can alter genetics in a way that increases susceptibility to these conditions from generation to generation.
  3. If someone develops a mental health condition first, they may turn to substances to cope with their symptoms and eventually develop a SUD. For example, studies have found that people with anxiety, depression, and post-traumatic stress disorder (PTSD) are more likely to self-medicate with illicit drugs and alcohol.
  4. Conversely, substance use can alter brain structure and function in a way that makes someone more susceptible to developing a mental illness.

The Difficulty of Treating Substance Use and Mental Health Simultaneously

Only 12.7% of Americans with co-occurring serious mental illness and SUDs received any treatment for both of their conditions in 2019. This is because even though these conditions frequently occur together, it’s difficult for providers to try and treat both simultaneously. Dual diagnosis typically leads to more severe symptoms, poorer treatment outcomes, increased risk of relapse in recovery, and higher rates of hospitalization when compared to either condition on its own. Diagnosing and treating these conditions simultaneously is made challenging by overlapping symptoms and interactions between certain substances and psychiatric medications.

In most instances, when someone with a dual diagnosis seeks treatment, they are doing it for the condition that is most disruptive to their lives – not necessarily for both. However, many people live with both conditions and never seek support. Both scenarios are concerning, as experts recommend treating mental illness and SUD simultaneously – preferably by seeing a specialist for each condition.

In this, there are two key points of intervention:

  1. Employing universal SUD and mental health screening at your practice to identify individuals who are dealing with a dual diagnosis, even if they’re not aware of it themselves.
  2. Performing comprehensive assessments for those seeking care for a mental illness or SUD to determine if they have a dual diagnosis and need additional support.

How You Can Support Your Patient Struggling with a Dual Diagnosis

As a PCP, you may be wondering where you come into the picture – and it’s right here. Primary healthcare is an entry point for many with dual diagnoses, and many of them are already visiting these practices for different health concerns or annual exams.

If you’re feeling hesitant about identifying and supporting these patients, you’re not alone. Less than 20% of physicians surveyed by AAFP felt very prepared to identify and address SUDs in their patients. Subsequently, over 50% of patients with substance use disorders said their PCP did nothing to address their substance use. The case is similar for mental health care, as training and knowledge in this subject varies widely between practitioners.

Screening for dual diagnosis is critical for providing comprehensive medical care and getting a full picture of your patient’s medical history. Ideally, primary care providers should feel prepared to identify these patients, perform a brief intervention, and form an action plan that involves referral to the appropriate specialists. This is based off the Screening, Brief Intervention & Referral to Treatment (SBIRT) model, which is an evidence-based approach to identify SUDs and reduce excessive use of substances. SBIRT can also be used effectively in dual diagnosis cases!

  1. Identify SUDs & Mental Health Conditions in Your Patients

According to SBIRT, about 20% of the adults you screen will require a brief intervention, and 5% will need a specialist referral. Here are some screening tools that can help you assess for SUD and mental health conditions:

  • BMH-7: An integrated screening; includes GAD-2 to screen anxiety, PHQ-2 to screen for depression, and AUDIT-C to screen for alcohol use.
  • GAD-7: Screens for anxiety.
  • PHQ-9: Screens for depression.
  • DAST-10: Screens for drug use.
  • AUDIT-C: Screens for alcohol use.
  1. Perform a Brief Intervention

If someone is experiencing harmful or risky substance use, SBIRT recommends performing a brief intervention right away. SBIRT offers a great handout for practitioners that explains when a screening indicates further intervention is necessary – download it here!

A brief intervention involves exploring the patient’s perspective of their substance use, asking for permission to give them information about the harms of substance use, assess their readiness to change, and help them determine a goal moving forward.

To further build your confidence in assessing, intervening, and managing both mental health and substance use in your practice, join us for REACH ABH: Adult Behavioral Health in Primary Care.

  1. Refer to Appropriate Specialists

For the 5% of patients who need a referral to a specialist, you can utilize the no-cost care navigation service on the Adult Psychiatric Access Line (APAL). Care navigators collaborate directly with your patient to connect them with accessible mental health, substance use, and other critical local resources. Our care navigators will follow up with your patient to help them navigate these referrals and minimize barriers they might encounter.

We hope this article has been helpful in increasing your understanding of substance use, mental illness, and how they intersect, as well as how to support these adult patients in your practice. For additional support, check out our provider education opportunities and learn more about APAL!