This assignment delves into the concept of the diathesis-stress theory, a fundamental model in psychology explaining the interplay between predispositions (diathesis) and environmental stressors in the development of psychological disorders. The assignment examines the historical background, core principles, and diverse applications of this theory across various mental health conditions, such as depression, anxiety, and schizophrenia. It also explores how the diathesis-stress model can be applied to understand real-world phenomena like substance abuse and parenting behaviors. The analysis is supported by relevant research studies and scholarly sources.