Significant life events, including personal losses and socio-cultural influences, led to the development of Sigmund Freud's theories on psychoanalysis. His relationship with his father, a strict figure, and his experiences treating patients in Vienna provided insights into the human psyche. Freud’s own struggles with anxiety and the cultural context of late 19th-century Europe also influenced his ideas about repression and unconscious motives. Major works, such as "The Interpretation of Dreams," reflect his innovative methods and theories about the mind. Freud’s interactions with other intellectuals led to the formation of his influential theories that revolutionized the understanding of mental health.