Comorbidity or Causation Between Mental Health and Substance Abuse?
submitted on 25 March 2019
It is no secret that many who develop substance abuse disorders are often also diagnosed with a mental health issue and vice versa—those who are diagnosed with a mental health issue often develop a drug addiction. In fact, there is a 50 percent probability that those who live with drug addiction have received or will receive a confirmed mental health diagnosis and vice versa. However, just because the two almost always seem to go hand in hand, does that mean one caused the other?
Which Came First: Substance Abuse or Mental Health Issues?
As the National Institute on Drug Abuse clarifies, the high prevalence of comorbidity between mental illness and drug or substance abuse does not necessarily mean that one caused the other, even if one appeared first. When it comes to establishing causation, researchers have a tough time doing so for several reasons.
For one, a person's symptoms of a behavioral disorder may not be severe enough to encourage drug use. When this happens, health care professionals refer to it as a subclinical diagnosis; however, studies also reveal a link between subclinical symptoms and substance abuse, so researchers cannot entirely rule out a correlation between the two.
Two, people who do abuse drugs often have a hard time remembering when their addiction first started. Also, those with mental illness may have imperfect memories, making it difficult to determine whether substance abuse or mental health issues appeared first.
A third factor that makes it difficult to establish causation is the fact that both mental illness and substance abuse share common risk factors. Those common risk factors are as follows:
• Genetic vulnerabilities
• Epigenetic vulnerabilities (which refers to the study of how changes that affect how cells in the body read and act upon genetic information)
• Issues with similar areas of the brain (for instance, the area of the brain that regulates reward, impulse control, decision making, and emotions may be disrupted by substance abuse, schizophrenia, depression, and other psychiatric disorders)
• Environmental influences, such as early exposure to trauma or stress
Pathways to Both Substance Abuse and Mental Illness Are Similar
In addition to sharing similar risk factors, the pathways to substance abuse and mental illness are parallel, making diagnosis and dual recovery even more difficult. For instance, it is a widely held belief that individuals with mild, severe, or subclinical mental disorders may take drugs as a sort of self-medication. Though some drugs do have the ability to reduce symptoms of mental illness momentarily, most end up exacerbating symptoms in the long term. For instance, several studies suggest that cocaine use can worsen symptoms of bipolar disorder and can even contribute to the progression of the illness.
Likewise, it is not unheard of for substance abuse to trigger the development of mental illness. Because substance abuse alters the way the brain functions, it can lead to disruptions in similar areas of the brain in which mental illness occurs. These disruptions can pave the way for mood disorders, schizophrenia, anxiety, and impulse control disorders.
Unfortunately, what research shows right now is that though there is a connection between mental illness and substance abuse, it is unclear whether there is causation. Regardless of the findings, however, what is clear is that individuals who live with both benefit greatly from dual recovery.