Inpatient Hospitalizations and Emergency Department Visits for Patients with a Behavioral Health Diagnosis in California: Patient Demographics

In 2021 and 2020, just over one-third of all Inpatient (IP) hospitalization patients had a behavioral health diagnosis.

What is Behavioral Health?

Behavioral health is an umbrella term that covers mental health (e.g., depression, anxiety disorders, schizophrenia and other psychoses) and substance use disorders. It includes our emotional, psychological, and social well-being. It helps determine how we handle stress, relate to others, and make healthy choices. Behavioral health is important at every stage of life, from childhood and adolescence through adulthood.

Why look at Behavioral Health Disorders?

According to the National Institute of Mental Health, nearly one in five U.S. adults live with a mental illness1. In California, that equates to nearly 8 million people in 2021.

According to the California Health Care Foundation, an average of 2.9 million Californians per year, age 12 and older (8.8%), had a substance use disorder in 2018-20192.

In 2021, patients with behavioral health diagnoses accounted for 1,216,356 Inpatient (IP) hospitalizations and 2,143,614 Emergency Department (ED) treat and release visits, which is approximately one third of all IP hospitalizations (3,557,587) and one fifth of all ED visits (10,907,850).

This data represents IP and ED behavioral health encounters during the COVID pandemic. Other studies have found an increase in behavioral health needs associated with the COVID pandemic. This information represents only one year of data. Subsequent years will be reported and may allow for an evaluation of the impact the COVID pandemic has had on behavioral health IP and ED encounters.

The visualizations below present patient demographic information (age, race/ethnicity, assigned sex at birth, and expected payer) for IP hospitalizations and ED visits for patients with a behavioral health diagnosis in California hospitals.  For these visualizations, “behavioral health diagnoses” have been divided into three categories: Mental Health Disorders, Substance Use Disorders, and Co-occurring Disorders (the patient has both Mental Health Disorders and Substance Use Disorders). This information includes behavioral health conditions identified as the primary and secondary diagnosis. The behavioral health information is limited to hospital settings and does not represent information on services delivered in other parts of the behavioral health delivery system.

Types of Behavioral Health Diagnoses

‘Behavioral health’ describes a wide range of disorders.  The visualization below gives a broad overview of the types of disorders being seen in the ED or during IP hospitalizations. 

  • For both care settings, there were nearly 964,000 encounters with a mood disorder present and just over 913,000 with an anxiety disorder.
  • Alcohol-related disorders were the third most prevalent category in both the ED and inpatient settings in 2021.

Note: Encounters with multiple behavioral health diagnoses will be counted for each separate diagnosis.

Key Demographic Findings

The findings below apply to 2021 demographic categories, but the patterns for 2020 are similar.

  • Age:  For age groups, care setting matters. Adults over age 60 comprised over 41 percent of IP hospitalizations, while younger adults (aged 19 to 39) comprised over 40 percent of ED visits.
  • Race/Ethnicity: Regardless of setting or type of disorder, Whites and Hispanics make up roughly 75 percent of encounters where there is a behavioral health diagnosis. The information is based on total numbers and not analyzed by the size each race/ethnicity group represents of the total population.
  • Assigned Sex at Birth: Males had a higher total number of diagnoses. Females are more likely to have a Mental Health Disorder and males are more likely to have a Substance Use Disorder.
  • Expected Payer: Medi-Cal and Medicare were the expected source of payment for over two-thirds of all encounters where a behavioral health diagnosis was present.

Note: For the visualizations below, the denominator is the total number of encounters within each of the behavioral health categories (Mental Health Disorders, Substance Use Disorders, and Co-Occurring Disorders).


  • The “60+” age group comprises half (50 percent) of all inpatient hospitalizations where a patient had a Mental Health Disorder diagnosis.
  • The “19 to 39” age group have the largest proportion of ED visits across all three behavioral health categories: Co-occurring, Mental Health Disorders, and Substance Use Disorders.
  • The “0 to 18” age group comprises the smallest proportion of ED visits and IP hospitalizations across all three behavioral health categories. Although a smaller proportion when compared to other age groups, the “0 to 18” age group had significantly more Mental Health Disorders compared to Co-occurring and Substance Use Disorders.

Note: Unknown age is not included.


  • For each of the behavioral health categories, Whites comprised just under half of the encounters regardless of care setting.
  • Asian/Pacific Islanders were more likely to be seen for a Mental Health Disorder than a Substance Use Disorder.
  • Hispanics presenting to the ED were equally as likely to be seen for a Mental Health Disorder or a Substance Use Disorder.

Note: Other Race/Ethnicity includes Multi-Racial, Other, Unknown, Invalid, and Missing.

Assigned Sex at Birth

  • Females account for the majority of ED visits and IP hospitalizations for Mental Health Disorders.
  • Males account for the majority of ED visits and IP hospitalizations for Substance Use Disorders.
  • Males are more likely than females to have a Co-occurring Disorder in both care settings.

Expected Payer

  • Medi-Cal was the most common expected primary payer for all disorders and healthcare settings with one exception – inpatient care for Mental Health Disorders. Medicare comprised nearly half of IP Mental Health Disorders.
  • In both care settings, Private Coverage covers more Mental Health Disorders than Co-occurring or Substance Use Disorders.
  • Uninsured patients were more likely to be treated in the ED for Substance Use Disorders than for Mental Health or Co-occurring Disorders.

1National Institute of Mental Health, Statistics, Mental Illness

2California Health Care Foundation, Substance Use in California, 2022: Prevalence and Treatment

How HCAI Created this Product:

  • Definitions for behavioral health categories were adopted from the Massachusetts Center for Health Information and Analysis, which consulted with clinicians and the Agency for Healthcare Research and Quality.
  • Clinical Classification Software Refined (CCSR) codes were used to define the categories: Mental Health Disorders (e.g., mood disorders; intentional self-harm, suicidal ideation, and suicide attempts; schizophrenia and other psychotic disorders), Substance Use Disorders (e.g., alcohol-related disorders; cannabis-related disorders, hallucinogens-related disorders), and Co-Occurring Disorders (at least one Mental Health Disorder and at least one Substance Use Disorder).
  • The visualizations include behavioral health diagnoses as a primary or secondary diagnosis but the counts may still be under-represented due to undiagnosed behavioral health conditions.
  • For the demographic visualizations, each patient encounter is counted one time.  Patients with at least one mental health diagnosis and at least one substance use diagnosis were placed in the “Co-occurring Disorder” group.

Additional Information

Topic: Healthcare Utilization
Source Link: Healthcare Quality
Citation: HCAI – Patient Discharge Data, Emergency Department Data – Hospital Encounters for Behavioral Health, 2021 – 2022
Temporal Coverage: 2020 – 2021
Spatial/Geographic Coverage: Statewide
Frequency: Annual