In Frontiers in Psychology, Belgian psychologist Eiko Fried argues for a different approach to understanding depression — not as a discrete disease, but as a cluster of otherwise independent symptoms that trigger and reinforce each other.
Fried reviews the history and limitations with the current disease model of depression and illustrates how a different approach would open new avenues of research and potential treatment. In his model, he writes, depression is not a discrete, underlying disease that causes a wide variety of symptoms; rather, it is a “network of symptoms that have direct causal influence on each other: insomnia can cause fatigue which then triggers concentration and psychomotor problems.”
“This network approach focuses on smaller and more valid and reliable units of observation – symptoms – that are likely associated with more distinct underlying pathophysiological processes,” writes Fried. “The framework not only acknowledges the highly heterogeneous nature of MD [major depression], its complexity, and its fuzzy boundaries, it also puts the focus on the dynamic interactions among symptoms that have received comparably little attention. The investigation of the differences between symptoms in terms of risk factors or biomarkers, as well as their causal pathways may be a great opportunity. In addition, future network studies could reveal that variables such as life stress, personality traits, and pathophysiology moderate specific symptom pathways: some individuals may be especially vulnerable to develop fatigue in response to insomnia, depending on their life situation or genetic background.”
Fried, Eiko I. “Problematic Assumptions Have Slowed down Depression Research: Why Symptoms, Not Syndromes Are the Way Forward.” Psychopathology, 2015, 309. doi:10.3389/fpsyg.2015.00309. (Full text)