Substance Abuse and the Brain

By Ashley Barnes, M.S.

Substance Abuse

According to the American Psychological Association (APA), substance abuse is defined as “a pattern of compulsive substance use marked by recurrent significant social, occupational, legal, or interpersonal adverse consequences, such as repeated absences from work or school, arrests, and marital difficulties” (2022). Addiction describes the “state of psychological or physical dependence (or both) on the use of alcohol or other drugs” (APA, 2022). Substance abuse goes hand in hand with addiction, as substance abuse can lead to addiction. 

Substance Use Disorder Symptoms

The following are symptoms of substance use disorders as outlined by The Johns Hopkins School of Medicine:

  • Using/drinking larger amounts or over longer periods of time than planned.
  • Continually wanting or unsuccessfully trying to cut down or control use of drugs or alcohol.
  • Spending a lot of time getting, using, or recovering from use of drugs or alcohol.
  • Craving, or a strong desire to use drugs or alcohol.
  • Ongoing drug or alcohol use that interferes with work, school, or home duties.
  • Using drugs or alcohol even with continued relationship problems caused by use.
  • Giving up or reducing activities because of drug or alcohol use
  • Taking risks, such as sexual risks or driving under the influence.
  • Continually using drugs or alcohol even though it is causing or adding to physical or psychological problems.
  • Developing tolerance or the need to use more drugs or alcohol to get the same effect. Or using the same amount of drugs or alcohol, but without the same effect.
  • Having withdrawal symptoms if not using drugs or alcohol. Or using alcohol or another drug to avoid such symptoms (2023).

What Causes Substance Use Disorder?

Substance use disorder is caused by a multitude of factors, including environmental stressors, genetic vulnerability, exposure to trauma, social pressures, and individual personality characteristics. 

Those experiencing mood disorders (ex: bipolar disorder, depression), anxiety disorders (ex: generalized anxiety disorder), post-traumatic stress disorder (PTSD), and psychotic disorders (ex: schizophrenia, schizoaffective disorder) may also have a co-occuring substance use disorder, as many people use substances as a means of attempting to manage and numb unpleasant psychiatric symptoms. 

For example, someone who suffers from an anxiety disorder may binge drink to reduce the physical symptoms associated with anxiety as a means of self-medicating; repeated use can lead to a substance use disorder and addiction.

Substance Abuse and the Brain

According to a new study published in Nature Mental Health, there is a common brain network among people with substance use disorders. The results of the study suggest that the same brain circuit may be a therapeutic target for addiction treatment.

Substance use stimulates the brain’s reward system, which is the brain circuit just referenced; dopamine, a neurotransmitter that is responsible for feelings pleasure, satisfaction, and motivation, is heavily involved in this brain neurocircuitry. However, the longer and more consistently someone uses a substance to achieve this dopamine spike, the less their brain will make its own dopamine. In other words, this means more of the drug will be required to achieve the same “reward” feeling over time – this is also known as tolerance to a substance.

“Additionally, the brain will respond with less dopamine to non-drug-related ‘rewards.’ Plus, not using drugs can mean withdrawal is a very negative physical experience, so the brain will crave more dopamine and more drugs” (Healthline, 2023). 

Addiction Psychiatrists affiliated with the Mental Health Center

We have several knowledgeable and compassionate physicians affiliated with the Mental Health Center who are ready to treat addiction and substance use disorders:

  • Mark Hrymoc, MDDr. Hrymoc is an expert in the psychopharmacology of addiction and other mental health disorders. He is board-certified in General Psychiatry, Addiction Psychiatry, and Addiction Medicine and holds an appointment as Assistant Clinical Professor of Psychiatry at UCLA, where he supervises training psychiatrists at their Addiction Psychiatry Clinic. He obtained his subspecialist training in Addiction Psychiatry at Cedars-Sinai Medical Center in Los Angeles. Dr. Hrymoc is a consulting physician to several prestigious drug and alcohol treatment centers in Los Angeles. Dr. Hrymoc is also one of the founders of the Mental Health Center.


  • Kimberly Brown, MD – Kimberly Brown, MD is double-boarded in General Psychiatry and Addiction Psychiatry. Dr. Brown received her medical degree from USC/Keck School of Medicine and completed her internship at Cedars-Sinai. She finished her residency at USC/Keck where she served as Chief Resident of Outpatient Services and received specialized training in psychodynamic, intensive short-term and cognitive behavioral therapy techniques. Following graduation, she pursued an Addiction Psychiatry Fellowship at the UCLA/Sepulveda Valley program. She has practiced in a variety of settings including the Veteran’s Administration, emergency psychiatry, and hospital based psychiatric services. She is a staff physician at Cedars-Sinai for the Consult-Liaison department. She provides psychiatric evaluations and medication management with special attention to individual requirements. She is flexible and integrative in her approach to meet the needs and desired outcomes of each person. 


  • Vicki Kalira, MD – Dr. Vicki Kalira is an expert in treating substance use disorders and is board certified in General Adult Psychiatry and Addiction Psychiatry. Dr. Vicki Kalira completed medical school at West Virginia University and her psychiatry residency at Johns Hopkins University. After completing a one-year addiction psychiatry fellowship at New York University (NYU), she supported hospitalized patients at NYU-Tisch Hospital as a Consultation-Liaison Psychiatrist. Here, her focus centered on providing care to patients with complex medical and psychiatric comorbidities who were experiencing acute intoxication or withdrawal. Dr. Kalira then transitioned to the Department of Veteran Affairs (VA), where she still provides crucial psychiatric support. Dr. Vicki Kalira is the Acting Medical Director for Addiction Recovery Treatment Services at the VA Northern California Health Care System, a critical leadership role.


  • Daniel Son, MD – Dr. Daniel Son is unique in having completed formal fellowship training in both Child & Adolescent and Addiction Psychiatry. He has a particular interest in the treatment of severe mental illness and adolescents with addiction issues. Dr. Son completed his medical degree at Loma Linda University and completed his Psychiatry residency and fellowships at the University of Louisville. Dr. Son focuses on providing thorough diagnostic interviews and providing medication management services. Dr. Son has received numerous awards during his training including the Gold Foundation Humanism and Excellence in Teaching Award, the Eli Lilly Chief Resident Leadership Program Award, and has several clinical and education awards.


  • Ellie Mizani, MD – Dr. Ellie Mizani is a psychiatrist specializing in child and adolescent psychiatry and addiction medicine. She is board-certified by the American Board of Psychiatry and Neurology. Dr. Mizani completed her undergraduate and medical studies at UC Irvine. She also completed her psychiatric and child and adolescent psychiatry subspecialty training at the UC Irvine Medical Center. During the last year of her child psychiatry training, Dr. Mizani served as Chief Fellow and graduated with commendation. Dr. Mizani also trained at the Semel Institute for Neuroscience and Human Behavior at UCLA, focusing on pediatric psychopharmacology for ADHD, mood disorders, anxiety disorders, and autism. Dr. Mizani is also one of the founders of the Mental Health Center.

Please contact our office at (310) 601-9999 or visit our Mental Health Center website to schedule an appointment today!



American Psychological Association (2022). Substance use, abuse, and addiction. American Psychological Association. Retrieved October 5, 2023, from

Healthline (2023). People With Substance Use Disorder Have Similar Brain Networks. Healthline. Retrieved October 5, 2023, from

Johns Hopkins School of Medicine (2023). Substance use disorder. Johns Hopkins School of Medicine. Retrieved October 5, 2023, from