Understanding the true nature of mental illness is essential for interpreting disparate research results, establishing accurate diagnostic profiles, setting robust research agendas, and optimizing therapeutic interventions. Psychopathology currently lacks a unifying framework. Mental Illness Defined: Continuums, Regulation, and Defense provides such a framework by filling the knowledge gap. Continuums, as opposed to numerous discrete entities, characterize mental illness. Impaired regulation fosters extreme expressions of mental illness continuums, an occurrence that can be compensated for by "cognitive regulatory control therapies." Defenses tend to moderate behavior, although excessive levels foster dysfunction, as with personality disorders. The model presented aligns with neuroscience and other relevant data, thereby placing psychopathology on a more scientific foundation to advance the aims of both researchers and treatment providers.