Harry Stack Sullivan developed interpersonal theory, which views personality as developing within social contexts. According to the theory, healthy development requires satisfying interpersonal relationships where intimacy and trust can grow. Anxiety arises from problems in relationships and can interfere with intimacy. The theory focuses on how people experience tension and needs, and how they act to reduce anxiety and fulfill needs through interpersonal interactions and dynamics like malevolence, lust, and intimacy. Development occurs through relationships with significant others from infancy through adolescence.