Sigmund Freud's psychoanalysis theory posits that childhood experiences significantly shape adult personality and behavior, with repressed emotions leading to mental health issues. The mind is structured into three layers: conscious, subconscious, and unconscious, with the ‘id’, ‘ego’, and ‘superego’ representing different aspects of human psyche. Freud's therapeutic goal is to bring unconscious thoughts to consciousness, allowing individuals to confront and resolve deep-seated issues.