Current information on treatment and clinical characteristics of U.S. adults with schizophrenia spectrum disorders (i.e., schizophrenia, schizoaffective, and schizophreniform disorders) may help inform public health policy and service development for this population.Data were from the U.S. Mental and Substance Use Disorders Prevalence Study, conducted from October 2020 to October 2022. Clinicians administered the Structured Clinical Interview for the DSM-5 for past-year psychiatric and substance use disorder diagnoses among adults ages 18-65 years. Using sampling weights, the authors examined clinical and treatment characteristics among those with schizophrenia spectrum disorders and compared sociodemographic characteristics and comorbid behavioral health conditions of individuals with or without such disorders (N=4,764).Among 114 adults with schizophrenia spectrum disorders, the most common comorbid conditions were major depressive episode (52%, 95% CI=34%-69%) and alcohol use (23%, CI=3%-43%), cannabis use (20%, 95% CI=1%-39%), and posttraumatic stress (17%, 95% CI=5%-30%) disorders. Global Assessment of Functioning scores were lower among people with than among those without schizophrenia spectrum disorders (mean±SE=44.8±2.0 vs. 77.2±0.5, p<0.01, respectively), indicating worse functioning. In the past year, 71% (95% CI=55%-87%) of adults with schizophrenia spectrum disorders received at least some mental health treatment, and 26% (95% CI=13%-38%) received minimally adequate treatment.Individuals with schizophrenia spectrum disorders face substantial challenges in the United States, including high rates of comorbid mental health conditions and substance use; few received adequate treatment. A strong social safety net and active clinical interventions are required to address the socioeconomic challenges and unmet mental health service needs of this population.