( ( ( ( ( Depression ( is ( ( the ( estimated ( leading cause ) ) ) ( of ( disability worldwide ) ) ) ) ) , ) and ) ( ( heart disease ) ( ( is ( by far ) ) ( ( the ( leading cause ) ) ( of ( death ( in ( the ( United States ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NNP Depression)) (VP (VBZ is) (NP (NP (DT the) (VBN estimated) (JJ leading) (NN cause)) (PP (IN of) (NP (NN disability) (NNS worldwide)))))) (, ,) (CC and) (S (NP (NN heart) (NN disease)) (VP (VBZ is) (ADVP (IN by) (RB far)) (NP (NP (DT the) (VBG leading) (NN cause)) (PP (IN of) (NP (NP (NN death)) (PP (IN in) (NP (DT the) (NNP United) (NNPS States)))))))) (. .)))
Depression is the estimated leading cause of disability worldwide, and heart disease is by far the leading cause of death in the United States.
(ROOT (S (NP (NNP Heart) (NN disease)) (VP (VBZ is) (NP (NP (DT the) (VBG leading) (NN cause)) (PP (IN of) (NP (NN death))) (PP (IN in) (NP (DT the) (VBN united) (NNS states))))) (. .)))