not be viewed as a depressive condition. Recent evidence, based on factor-analytic and meta-analytic findings, calls into question this supposition. Burnout is also now often seen as involving the full array of depressive symptoms (e.g., low mood, cognitive alterations, sleep disturbance). Marked differences among researchers' conceptualizations of what constitutes burnout have underlined the need for a consensus definition. Subtypes In 1991, Barry A. Farber in his research on teachers proposed that there are three types of burnout: "wearout" and "brown-out," where someone gives up having had too much stress and/or too little reward "classic/frenetic burnout," where someone works harder and harder, trying to resolve the stressful situation and/or seek suitable reward for their work "underchallenged burnout," where someone has low stress, but the work is unrewarding. Farber found evidence that the most idealistic teachers who enter the profession are the most likely to suffer burnout. Caregiver burnout Burnout affects caregivers. Relationship with other conditions A growing body of evidence suggests that burnout is etiologically, clinically, and nosologically similar to depression. In a study that directly compared depressive symptoms in burned out workers and clinically depressed patients, no diagnostically significant differences were found between the two groups; burned out workers reported as many depressive symptoms as clinically depressed patients. Moreover, a study by Bianchi, Schonfeld, and Laurent (2014) showed that about 90% of workers with very high scores on the MBI meet diagnostic criteria for depression. The view that burnout is a form of depression has found support in several recent studies. Some authors have recommended that the nosological concept of burnout be revised or even abandoned entirely given that it is not a distinct disorder and that there is no agreement on burnout's diagnostic criteria. A newer generation of studies indicates that burnout, particularly its exhaustion dimension, problematically overlaps with depression; these studies have relied on more sophisticated statistical techniques, for example, exploratory structural equation modeling (ESEM) bifactor analysis, than earlier studies of the topic. The advantage of ESEM bifactor analysis, which combines the best features of exploratory and confirmatory factor analysis, is that it provides a granular look at item-construct relationships, without falling into traps earlier burnout researchers fell into. Liu and van Liew wrote that "the term burnout is used so frequently that it has lost much of its original meaning. As originally used, burnout meant a mild degree of stress-induced unhappiness. The solutions ranged from a vacation