Psychiatric conditions and sub-threshold psychiatric temperaments may influence entrepreneurs' affect, cognition, energy, motivation, circadian rhythms, activity levels, self-concept, creativity, and interpersonal behaviors in ways that influence business outcomes. We used a self-report survey to examine the prevalence and co-occurrence of five psychiatric conditions among 242 entrepreneurs and 93 comparison participants. Mental health differences directly or indirectly affected 72% of the entrepreneurs in this sample, including those with a personal mental health history (49%) and family mental health history among the asymptomatic entrepreneurs (23%). Entrepreneurs reported experiencing more depression (30%), ADHD (29%), substance use (12%), and bipolar disorder (11%) than comparison participants. Furthermore, 32% of the entrepreneurs reported having two or more mental health conditions, while 18% reported having three or more mental health conditions. Asymptomatic entrepreneurs (having no mental health issues) with asymptomatic families constituted only 24% of the entrepreneur participants. Entrepreneurs' psychiatric issues can affect their functioning and that of their ventures. Therefore, integrating knowledge about psychiatric conditions with research on personality traits can broaden the understanding of how mental healthrelated traits, states, and family history can influence entrepreneurial outcomes. We discuss methodological limitations as well as implications of our findings for entrepreneurship research and practice.