I wouldn't say burnout is just an office cliche, but your point appears to be supported by current research. Quoth the wiki:
> The symptoms of burnout are similar to those of clinical 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 burned out workers meet diagnostic criteria for depression, suggesting that burnout may be a depressive syndrome rather than a distinct entity. The view that burnout is a form of depression has found support in several recent studies.
> The symptoms of burnout are similar to those of clinical 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 burned out workers meet diagnostic criteria for depression, suggesting that burnout may be a depressive syndrome rather than a distinct entity. The view that burnout is a form of depression has found support in several recent studies.
https://en.wikipedia.org/wiki/Burnout_%28psychology%29