Schizophrenia and Substance Abuse: What We Know About the Connection

Contributor: Rachael Mattice is the Content Manager for Sovereign Health Group, an addiction, mental health and dual diagnosis treatment provider. Rachael received her bachelor’s degree in journalism and mass communication from Purdue University.

Cool handsome guySchizophrenia is a severe brain disorder characterized by delusions, hallucinations, paranoia and other psychotic features. A spectrum of chronic and potentially disabling conditions, schizophrenia is often characterized by exacerbations and remissions.

Back in 1990 when the landmark Epidemiologic Catchment Area (ECA) Study1 was published in the Journal of the American Medical Association, between 1 and 2 percent of the U.S. population had schizophrenia. No study to date has been as large and thorough as the 1990 ECA study, which is still widely used today as a reference for epidemiological data in this population.

Up to 10 percent of individuals with a schizophrenic family member develop the disorder, according to the National Institute of Mental Health (NIMH)2 .

The DSM-5

Schizophrenia is now classified as a spectrum disorder according to the 2013 “Diagnostic and Statistical Manual of Mental Disorders,” Fifth Edition (DSM-5) by the American Psychiatric Association. Diagnosis is based on symptom characteristics, such as delusions, and etiology, such as substance use.

Although no known cure exists, effective treatments are available that promote safety, functionality and quality of life. Treatment consists of antipsychotic medications and various types of psychosocial therapy. Underlying or co-occurring substance abuse must also be treated.

Co-occurring Substance Use Disorders

young man outdoorsSubstance abuse has long been associated with schizophrenia and related disorders. In fact, 47 percent of schizophrenics met criteria for some form of substance use disorder, according to the ECA study.

Methamphetamine, hallucinogens, cocaine, marijuana and phencyclidine (PCP), in particular, have been known for decades to be linked to co-occurring schizophrenia, as well as to a prior diagnosis. This fact has led to some ambiguity regarding the cause-effect relationship between substance abuse and schizophrenia.

Many genetic and environmental factors go into the development of schizophrenia, so it is very difficult to determine whether substances are used to self-medicate symptoms before diagnosis or if substances cause or trigger underlying psychopathology.

Treatment for Co-occuring Substance Use Disorders

In any case, once a substance use disorder has been identified in a patient with schizophrenia, treatment should begin immediately. Untreated, symptoms are usually exacerbated and patients tend not to adhere to treatments plans. Though violence is not particularly common with schizophrenia, substance use can increase the risk for violence and suicide, according to the NIMH.

Nora D. Volkow, M.D., of the National Institute on Drug Abuse stated, “… the factors influencing substance use disorder risk in schizophrenia may be more numerous and/or complex than … the general population. It is critically important to address this comorbidity because substance use disorder in schizophrenic patients is associated with poorer clinical outcomes and contributes significantly to their morbidity and mortality.” She further discussed clinical applications of these issues in her article3 in the May 2009 Schizophrenia Bulletin.

Alcohol and Drug Abuse

Young man having depressionThe ECA study also revealed that 34 percent of those with schizophrenia abused alcohol and 28 percent abused other drugs. Cocaine was the most frequently used drug in this group, followed by opiates, hallucinogens, barbiturates, miscellaneous other drugs, marijuana and amphetamines, respectively.


Tobacco is the most commonly abused drug in the schizophrenic population, but was not included in the ECA study. A wide range of data regarding tobacco use among schizophrenics exists. The NIMH estimates that 75 to 90 percent of the schizophrenic population smokes, significantly more than the general population, 25 to 30 percent of whom smokes. In addition, samples from the U.S. showed higher smoking rates than worldwide samples.

According to the National Association of State Mental Health Program Directors 2006 publication4 , Morbidity and Mortality in People with Serious Mental Illness, these individuals die an average of 25 years earlier than the general population. To help reduce this risk, tobacco use should be addressed when treating schizophrenic patients who smoke.


Caffeine acts on the same brain mechanisms as schizophrenia and antipsychotic medications. In addition, anecdotal evidence in the literature suggests an overall high caffeine intake in the schizophrenic population, but no survey data in the U.S. has been gathered yet.

John Hughes, M.D., and colleagues reviewed available research data in their November 1998 column5 in Psychiatric Services. They explored caffeine’s effect on the brain and on psychotic symptoms, and the interaction between caffeine and antipsychotic pharmaceuticals.

The data was sparse and inconsistent regarding caffeine’s effect on the brain of schizophrenic patients. They found that high doses of caffeine could increase negative psychotic symptoms, except in patients who had a high intake on a regular basis. Withdrawing caffeine did not affect psychotic symptoms either way. Data suggested that caffeine might inactivate neuroleptics and increase blood levels of clozapine. More research is needed to delineate these effects.

Schizophrenia Symptoms

Schizophrenia symptoms are not known to be related to any specific substance of abuse. Those abusing drugs and alcohol often suffer from severe socioeconomic problems like homelessness. Many are also at risk for other medical conditions, such as malnutrition or HIV/AIDS.

Dual Diagnosis Treatment

Man with his dogInitial treatment goals for dually diagnosed patients should focus on medical stabilization physically and mentally, crisis management, diagnosis before and after detoxification, and a treatment plan. Initial treatment might occur in a hospital emergency room or an integrated treatment center.

Once stabilized, the therapeutic phase of treatment begins. Centers specializing in dual diagnosis treatment offer the collaboration between psychiatry and substance abuse treatment.

John Tsuang, M.D., and Timothy Fong, M.D., with UCLA’s David Geffen School of Medicine, published a comprehensive article6 on the treatment of patients with schizophrenia with substance use disorders in the January 2004 issue of Current Pharmaceutical Design. They noted necessary factors for dual diagnosis treatment programs, including:

  • Close collaboration between psychiatry and addiction medicine to individualize a medical regimen.
  • Addiction counselors who are knowledgeable about schizophrenia and won’t confuse its symptoms or antipsychotic medication side effects with noncompliant behavior
  • Therapists who consider cognitive impairment, psychotic symptoms and medication side effects in relation to cognitive-based therapeutic strategies

Non-Pharmacological Therapeutic Methods

Some non-pharmacological therapeutic methods for dual diagnosis patients that Tsuang and Fong reviewed included case management, motivational interviewing, 12-step groups, cognitive behavioral training, social skills training, contingency management, family training and education, and harm reduction.

The aftercare and maintenance plan is also very important. These, in conjunction with an effective medication regimen, provide schizophrenic patients with the best opportunity for positive outcomes.

Community Discussion – Share your thoughts here!

What has been your experience with Schizophrenia and Addiction recovery? What support systems do you have in place to support you in your recovery?

About the Author:

Rachael Mattice is the Content Manager for Sovereign Health Group, an addiction, mental health and dual diagnosis treatment provider. Rachael is a creative and versatile journalist and digital marketing specialist with an extensive writing and editing background.

Her portfolio includes numerous quality articles on various topics published in print and digital formats at award-winning publications and websites. To learn more about Sovereign Health Group’s mental health treatment programs and read patient reviews, visit Follow Sovereign Health Group on Twitter, Facebook, Google+ and LinkedIn.

The opinions and views of our guest contributors are shared to provide a broad perspective of addiction. These are not necessarily the views of Addiction Hope, but an effort to offer discussion of various issues by different concerned individuals.


  1. Comorbidity of mental disorders with alcohol and other drug abuse. Results from the Epidemiologic Catchment Area (ECA) Study. (1990, January 1). Retrieved April 1, 2015, from
  2. Schizophrenia. (n.d.). Retrieved April 1, 2015, from
  3. Schizophrenia Bulletin. (2015, January 1). Retrieved April 1, 2015, from
  4. Morbidity and Mortality in People with Serious Mental Illness. (2006, October 1). Retrieved April 1, 2015, from and Morbidity Final Report 8.18.08.pdf
  5. Caffeine and schizophrenia. (1988, November 1). Retrieved April 1, 2015, from
  6. Treatment of patients with schizophrenia and substance abuse disorders. (2004, January 1). Retrieved April 1, 2015, from

Last Updated & Reviewed By: Jacquelyn Ekern, MS, LPC on May 1st, 2015
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