Exploring Substance-Induced Schizophrenia and Why Integrated Treatment is Necessary

The high-rate of co-occurrence between schizophrenia and substance use disorders has led many within the medical community to explore drug-induced schizophrenia. By examining the available evidence, you can come to better understand current debates about the impact of drug use on the onset of schizophrenia as well as on existing schizophrenia. While there is still much to learn, what is clear is that integrated treatment is essential when schizophrenia and substance use disorders co-occur.

The diagnosis of schizophrenia is just over 100 years old, coined by Swiss psychiatrist Eugen Bleuler in 1908. However, its existence spans much further, evidenced in texts such as the Hindu Arthava Veda (1400 BC), The Yellow Emperor’s Classic of Internal Medicine (1000 BC), and ancient Greek and Roman writings. Despite the disparity in geography and time, the authors of these texts all attributed the origins of the illness to the same cause: supernatural and demonic forces. Such beliefs persisted for centuries before medical science finally began to uncover real answers.

Today, we understand schizophrenic symptomatology as the result of a medical illness with biological roots. And yet, there is still so much we have yet to learn about its origins. Now, scientists are taking a closer look at the impact of substance abuse on illness onset and exploring the topic of substance-induced schizophrenia. Research is ongoing, but one thing has become increasingly apparent: integrated treatment which addresses both the disorder and any co-occurring addictions may not just be important but, in many cases, necessary in order to truly begin healing both the body and the mind.

The High Rate of Co-Occurrence


Schizophrenia is notorious for its high rate of co-occurring substance abuse, with nearly half of patients experiencing a substance use disorder in their lifetime. This extraordinary overlap has led to growing interest in understanding the relationship between schizophrenia and substance use. Marijuana use has been an area of particular interest, as “rates of cannabis use disorder as high as 53% have been reported in some studies of patients with first-episode schizophrenic psychosis.”

In recent years, a number of compelling studies have emerged suggesting a link between marijuana use and the emergence of schizophrenia in teenagers and young adults. A 2011 study published in the British Medical Journal found that young people who used marijuana were twice as likely to experience psychosis within 10 years as those who did not. A study on young Swedish soldiers, meanwhile, found that marijuana users were twice as likely to develop schizophrenia as non-users and the heaviest users were six times as likely to develop the illness.

A number of studies also suggest that marijuana use is linked to earlier onset of schizophrenia, with one meta-analysis concluding that onset was hastened by nearly three years. It is important to note, however, that other research suggests that evidence of such an effect disappears once demographic and clinical variables are accounted for.

Drug-Induced Schizophrenia: What the Evidence Tells Us


While the correlation between marijuana use and schizophrenia is undeniable, a clear causal relationship has yet to be established. Some researchers are adamant that there is a direct link between the two, while other researchers dispute the idea that marijuana can cause schizophrenia, particularly in those without familial predisposition. So what accounts for the high rate of co-occurrence?

  • Smoking marijuana may increase vulnerability to psychotic illness. As Ann McDonald of Harvard Health points out, some experts believe that smoking marijuana may “derail” the process of normal brain development in adolescence and young adulthood, increasing vulnerability to disorders such as schizophrenia.
  • Schizophrenia may make marijuana use more pleasurable. A small study in the Netherlands found that people with schizophrenia appear to have a heightened sensitivity to the positive effects of marijuana. According to Cecile Hanquet, one of the study’s authors, “People feel better when they use cannabis, and that’s logical, because otherwise they wouldn’t use cannabis.”
  • There may be an overlap in genetic predisposition. A 2014 study published in Molecular Psychiatry discovered that “part of the association between schizophrenia and cannabis use [may be] due to a shared genetic aetiology.” In other words, people who have an elevated genetic risk of schizophrenia also have an elevated risk of marijuana use. Wolfram Kawohl, a psychiatrist at the University of Zurich, believes the findings show that it may be possible for schizophrenia to cause substance use, substance use to cause schizophrenia, and substance use and schizophrenia to manifest alongside each other due to shared origins.

The Impact of Substance Use on Existing Schizophrenia


The exact relationship between marijuana use and the onset of schizophrenia remains an area of scientific debate, and more research is needed to establish a causative effect. What we do know, however, is that while people with schizophrenia may be more sensitive to the positive effects of marijuana in the short term, marijuana use ultimately aggravates schizophrenia symptoms.

“What the data clearly show are that, if anything, the core symptoms of schizophrenia actually get worse after using cannabis,” says Deepak Cyril D’Souza, a psychiatrist at Yale University. In fact, the is a large body of research demonstrating that substance use in general—not just marijuana—is “associated with poorer outcomes in psychosis and higher rates of presentation to inpatient and emergency services.” Additionally, people with schizophrenia who use drugs are less responsive to psychiatric medications, complicating treatment and compromising outcomes.

The Need for Integrated Dual Diagnosis Treatment


The relationship between substance abuse and schizophrenia is complex and not yet fully understood. What is clear, however, is that both disorders must be treated together in order to achieve the best possible outcomes due to their deeply interdependent nature. If your loved one is struggling with schizophrenia and a co-occurring substance use disorder, dual diagnosis treatment is essential to addressing the full scope of their needs.

Dual diagnosis treatment is an integrative approach designed to treat mental health disorders and substance use disorders simultaneously. Without the interference of illicit drugs, your loved one can be thoroughly assessed to gain a full picture of their experience. This can then be used to establish a course of pharmacological treatment uncompromised by substance abuse, giving your loved one the best chance possible at healing and regaining some sense of normalcy and independence in their life. Using pharmacotherapy in combination with evidence-based therapeutic modalities that promote insight and the development of coping skills, clinicians are able to help clients effectively break through the cycle of use and suffering.

Unfortunately, most dual diagnosis treatment programs are relatively short in duration, often lasting no longer than 90 days. For people with complicated illnesses like schizophrenia and a co-occurring substance use disorder, this is typically not enough time to make significant progress toward recovery, particularly if someone struggles with low function. By seeking out a long-term dual diagnosis treatment program, your family member is given the time, structure, and sustained skill-building necessary to create meaningful and lasting change. With the right kind, quality, and duration of care, your loved one can find freedom from substance abuse and learn to effectively manage their schizophrenia in healthy ways, opening up the door to profound transformation and lasting wellness.

Hanbleceya offers comprehensive treatment for people struggling with mental health disorders as well as co-occurring substance use disorders. Contact us to learn more about our renowned San Diego-based program and how we can help you or your loved one start the journey toward recovery.

Image Source: Unsplash user Greg Raines