People believe that treatments for illnesses are effective when they target the cause of the illness. Prior work suggests that biological essentialist explanations of mental illness lead people to prefer medications or other pharmacological treatments. However, prior work has not distinguished between biological and essentialist explanations. In three studies (total n = 517), we presented adults with vignettes about an individual with an artificial mental illness and manipulated the descriptions to emphasize or de-emphasize essentialist characteristics. Critically, none of the vignettes made reference to a biological basis for the disorder. Participants rated their willingness to interact with the person described in the vignettes and how effective they believed drug treatment and talk therapy would be on the mental illness. Across the three studies, describing mental illness with an essentialist framing led participants to think drug treatments would be more effective, but there was no effect for stigma or perceived effectiveness of talk therapy. This effect appears to be mediated by how much participants essentialized individuals with the disorder. The first framing that participants encountered seemed to shape their reasoning for the remainder of the study, even if they saw conflicting framing later on. The framing manipulation had similar effects for individuals with and without a mental illness. Results suggest that it is important to consider how mental illness is framed to the general public as it might impact people’s treatment preferences..