[Clin Psychol Sci Prac 18: 300–304, 2011]
To improve our understanding of how to treat depression, an important step will be to identify processes that are causally implicated in the maintenance of the disorder. This could be achieved with longitudinal research or, more optimally, with randomized experiments that manipulate putative maintaining processes. This work would also ideally contribute to the development of models that integrate discoveries across levels of analysis (e.g., psychological, neural, genetic, behavioral). Conducting such interdisciplinary work is not easy, but it could facilitate a more comprehensive understanding of processes that maintain depression. Armed with this knowledge, synergistic treatments could then be developed to modify specific maintaining processes and alter the course of depression.