Substance use is a serious concern in California, where fentanyl has driven one of the sharpest overdose surges in the country. Key figures:

• Close to 8,000 opioid-related overdose deaths in 2023, according to the California Department of Public Health.
• Fentanyl is involved in 63% of all fatal overdoses.
• Fentanyl accounts for 91% of opioid-related deaths.
• Fentanyl-related deaths rose more than 800% from 2018 to 2023.
• Methamphetamine and other stimulants also contribute significantly to fatal overdoses.
• Overdose deaths declined about 25% in 2024, a hopeful turn after the surge.

Fentanyl’s arrival transformed the crisis, pushing deaths to historic highs before a recent decline offered a hopeful turn. California’s overdose totals are among the largest in the nation simply because of its population, and the state’s treatment landscape is the largest in the directory.

California expanded Medi-Cal in 2014 under the Affordable Care Act, and the state’s Medicaid program covers substance use disorder treatment. The Department of Health Care Services (DHCS) oversees the state’s behavioral health system. Of the 1,141 facilities listed below, 529 accept Medicaid.