This review article explores the physiological and clinical consequences of sustained elevations in antidiuretic hormone (ADH) and cortisol levels, focusing on their independent and overlapping complications. Elevated ADH, commonly seen in syndrome of inappropriate antidiuretic hormone secretion (SIADH), results in water retention and hyponatremia, which can lead to acute neurological symptoms such as seizures and coma, and chronic complications including cognitive decline, gait disturbances, and osteoporosis. Elevated cortisol levels, as seen in endogenous Cushing’s syndrome or with prolonged glucocorticoid therapy, are associated with systemic complications including hypertension, insulin resistance, visceral obesity, muscle wasting, osteoporosis, neuropsychiatric disorders, immune suppression, and increased cardiovascular risk. The review also addresses the diagnostic challenges in differentiating SIADH from adrenal insufficiency or other electrolyte disorders, especially in hospitalized or postoperative patients. Additionally, the interplay between cortisol and ADH regulation is discussed, emphasizing the complex neuroendocrine feedback mechanisms involved. Early recognition and appropriate management of these hormonal imbalances are critical to reducing morbidity and improving long-term outcomes.