dysthymia

A tendency to be depressed, without hope.

Other [subway] passengers showed no outward signs of distress. They appeared to have homes and money and good health, they carried briefcases or bags. … Their faces didn't cave in despair or trouble or strain. But they still had a walled-off look, their brows furrowed, their eyes cast deep into their newspapers or their laps. They looked so dissatified and burdened and checked-out. As if the weight of the world bore down on them, and something vital was missing. The clinical term for this is "dysthymia"―the low-grade feeling that life is unfulfilling. It feels like emptiness. Hunger. Disillusionment. Life is not what you'd hoped. It's a less severe version of what I saw every day on the inpatient ward: alienation, isolation, futility, darkness. And it's what I recognised in my husband and many of our friends. We were young, in our twenties, full of energy and professional drive, committed to living and working in a way that contributed to the world. But sometimes the rush and buzz of our day-to-day felt more like treadmill than calling.

A form of clinical depression, characterized by low-grade depression which lasts at least two years.

For diagnostic, research, and treatment reasons, a distinction should always be made between the milder dysthymias, atypical and hysteroid depressions, and the more serious major depressive illnesses, with and without melancholic (vegetative) and psychotic features.

A decade ago most psychiatrists would have been puzzled to find a chapter on dysthymia in a book about severe depressive disorders. They would have characterized this chronic form of depression as mild, "minor," or "syndromal."[…]In recent years, research has demonstrated the severity, prevalence, and importance of vogorous antidepressant treatment of dysthymia, justifying its inclusion here among serious mood disorders.