Talkiest stix ever. I should just make this plain text and not pretend that the visual component is important. On the other hand I do like our expressions.
The term "dysthymia" did exist in Walter Freeman's time, but it was rarely used. The first two versions of the Diagnostic and Statistical Manual of Mental Disorders list another thing called "neurotic depression," but in 1980 the makers of the DSM-III got rid of it and replaced it with dysthymic disorder, in part because no one could agree on precisely what neurotic depression was. You were chronically gloomy and no fun to be around, yes, and you didn't have hallucinations, because that would be a psychosis, right, but beyond that, what? You were just kind of...not OK. To which my teenage self would have said, "Exactly." But you want something more concrete from a mental health professional.
Nor can anyone agree on how close an equivalent dysthymic disorder is: some people say it's pretty much the same thing, while others say it's very different.
Interestingly, from what I can tell, neurotic depression was listed under Axis II -- the personality disorders. The idea was that you were born with it and you were stuck with it forever. Eek! Pioneering psychiatrist Emil Kraepelin (who may have invented the term, no one will give me a straight answer on this), was of the opinion that neurotic depression wasn't even an illness. That's just the personality you got dealt; sorry. And indeed that is precisely how dysthymia makes you feel. It was positively spooky for me to read this part of the DSM-IV entry for the first time: "Because these symptoms have become so much a part of the individual's day-to-day experience (e.g., 'I've always been this way,' 'That's just how I am'), they are often not reported unless directly asked about by the interviewer." Get out of my head, editors of the DSM-IV! Did Emil Kraepelin tell you that about me? STOP FOLLOWING ME, EMIL KRAEPELIN!