OBJECTIVE: Individuals with serious mental illness (SMI) are dying on average 25 years prematurely. The leading causes are chronic preventable diseases. In the context of a tobacco-treatment trial, this exploratory study examined the behavioral risk profiles of adults with SMI to identify broader interventional needs.METHOD: Recruited from five acute inpatient psychiatry units, participants were 693 adult smokers (recruitment rate = 76%, 50% male, 45% Caucasian, age M = 39, 49% had income < $10,000) diagnosed with mood disorders (71%), substance-use disorders (63%), posttraumatic stress disorder (39%), psychotic disorders (25%), and attention deficit-hyperactivity disorder (25%). The Staging Health Risk Assessment, the primary measure used in this study, screened for risk status and readiness to change 11 health behaviors, referencing the period prior to acute hospitalization.RESULTS: Participants averaged 5.2 (SD = 2.1) risk behaviors, including smoking (100%), high-fat diet (68%), inadequate fruits/vegetables (67%), poor sleep (53%), physical inactivity (52%), and marijuana use (46%). The percent prepared to change ranged from 23% for tobacco and marijuana to 76% for depression management. Latent class analysis differentiated three risk groups: the global higher risk group included patients elevated on all risk behaviors; the global lower risk group was low on all risks; and a mood and metabolic risk group, characterized by inactivity, unhealthy diet, sleep problems, and poor stress and depression management. The global higher risk group (11% of sample) was younger, largely male, and had the greatest number of risk behaviors and mental health diagnoses; had the most severe psychopathologies, addiction-treatment histories, and nicotine dependence; and the lowest confidence for quitting smoking and commitment to abstinence.CONCLUSION: Most smokers with SMI engaged in multiple risks. Expanding targets to treat co-occurring risks and personalizing treatment to individuals' multibehavioral profiles may increase intervention relevance, interest, and impact on health.