She is undergoing therapy to cope with the depression that have been troubling her for a long time.

depression 由前缀 de-（表示"向下"）和词根 press（"压"）加上名词后缀 -ion 构成，字面意思是"向下压的状态"。在心理学领域指"抑郁症"，表现为持续的情绪低落和兴趣丧失。