Paul Eugen Bleuler was a Swiss psychiatrist and humanist most notable for his contributions to the understanding of mental illness. He coined several psychiatric terms including "schizophrenia", "schizoid", "autism", depth psychology and what Sigmund Freud called "Bleuler's happily chosen term ambivalence".

Sigmund Freud was an Austrian neurologist and the founder of psychoanalysis, a clinical method for evaluating and treating pathologies seen as originating from conflicts in the psyche, through dialogue between patient and psychoanalyst, and the distinctive theory of mind and human agency derived from it.