Developmental cascades refer to the cumulative effects of interactions and transactions across different systems, levels, and domains of development, influencing the course of ontogenesis and epigenesis. These cascades can be direct or indirect, and their consequences are long-lasting, shaping development over time. They have been referred to by various names, including chain reactions, snowball effects, and spillover effects. The concept is central to developmental psychopathology, where both adaptive and maladaptive functions can spread over time, affecting development. For example, some childhood problems predict adult difficulties, while others do not. Cascade effects may explain comorbidity in disorders like conduct disorder and the transmission of behavior across generations. Interventions targeting mediating processes can interrupt negative cascades or promote positive ones. Cascade models suggest that early interventions in childhood can have significant long-term benefits, as seen in high-quality preschool programs. Cascade effects occur across multiple levels of function, from molecular to macro levels, and can involve gene-environment interactions. They may flow downward, upward, or across domains, influencing behavior, brain development, and psychopathology. Pharmacological interventions can induce upward cascades by altering neural function. Biological embedding of experience, such as through trauma, can lead to cascading effects on brain development and symptoms of psychopathology. Developmental cascades can be positive or negative, with positive cascades fostering competence in new domains. Failure in key developmental tasks can have lasting consequences for psychological well-being. The dual failure model suggests that early problems in family and school contexts can lead to academic and social difficulties, increasing the risk of depression and antisocial behavior. Cascade models are supported by longitudinal studies, including the Fast Track study and Project Competence. However, testing these models is challenging due to the need for longitudinal data, repeated assessments, and complex statistical methods. Interventions must consider the timing and mechanisms of cascades to be effective. Research on cascades highlights the importance of understanding how early experiences influence later outcomes. Cascade models provide insights into pathways of adaptation, maladaptation, and resilience, informing the design of preventive interventions. Despite challenges in testing, cascade research offers valuable insights into the complex processes of development and psychopathology.Developmental cascades refer to the cumulative effects of interactions and transactions across different systems, levels, and domains of development, influencing the course of ontogenesis and epigenesis. These cascades can be direct or indirect, and their consequences are long-lasting, shaping development over time. They have been referred to by various names, including chain reactions, snowball effects, and spillover effects. The concept is central to developmental psychopathology, where both adaptive and maladaptive functions can spread over time, affecting development. For example, some childhood problems predict adult difficulties, while others do not. Cascade effects may explain comorbidity in disorders like conduct disorder and the transmission of behavior across generations. Interventions targeting mediating processes can interrupt negative cascades or promote positive ones. Cascade models suggest that early interventions in childhood can have significant long-term benefits, as seen in high-quality preschool programs. Cascade effects occur across multiple levels of function, from molecular to macro levels, and can involve gene-environment interactions. They may flow downward, upward, or across domains, influencing behavior, brain development, and psychopathology. Pharmacological interventions can induce upward cascades by altering neural function. Biological embedding of experience, such as through trauma, can lead to cascading effects on brain development and symptoms of psychopathology. Developmental cascades can be positive or negative, with positive cascades fostering competence in new domains. Failure in key developmental tasks can have lasting consequences for psychological well-being. The dual failure model suggests that early problems in family and school contexts can lead to academic and social difficulties, increasing the risk of depression and antisocial behavior. Cascade models are supported by longitudinal studies, including the Fast Track study and Project Competence. However, testing these models is challenging due to the need for longitudinal data, repeated assessments, and complex statistical methods. Interventions must consider the timing and mechanisms of cascades to be effective. Research on cascades highlights the importance of understanding how early experiences influence later outcomes. Cascade models provide insights into pathways of adaptation, maladaptation, and resilience, informing the design of preventive interventions. Despite challenges in testing, cascade research offers valuable insights into the complex processes of development and psychopathology.