books.google.com.au - Major depressive disorder is highly prevalent, recurrent, and associated with inter-episodic dysfunction. Individuals with severe depression exhibit profound morbidity, co-morbidity, disability, cost, and mortality. Severe depression is a heterogeneous phenotype with a lack of standardized definition....https://books.google.com.au/books/about/Severe_Depression.html?id=TpJdvJsp8S4C&utm_source=gb-gplus-shareSevere Depression
