The phrase "a depressing turn" is correct and usable in written English.
It can be used to describe a situation or narrative that has taken a negative or disheartening direction.
Example: "The story started off lighthearted, but it took a depressing turn when the main character faced unexpected tragedy."
Alternatives: "a disheartening shift" or "a bleak change".
Even by the standards of recent years, this is turning into a depressing Tour for the home nation, and spirits will not have been raised one millimetre after the announcement yesterday by last year's French darling, Laurent Jalabert, that this is his last Tour.
There had been plenty of chest-thumping, obnoxious arrogance ahead of the Spain game, but events took a thoroughly depressing turn after Germany were confirmed as England's semi-final opponents.
A depressing number of threads in my network turned out to lead nowhere, even though they looked very promising at first.
There is absolutely nothing to cheer as the story of the 22-year-old high school basketball impostor in Texas takes another depressing turn: a 16-year-old girl's complaint has prompted sexual assault charges against him.
Our news diet this week took a depressing, gender-based turn after we read a disheartening report about how science is still viewed as a male profession around the world.
2.04pm BST If this turns into a depressing thumping can we have some alternative riffs?
But what started out looking like a disheartening rout morphed into a sloppy but surprisingly compelling game, only to turn back into a depressing loss for the few home fans who remained to watch it all.
After he said that, I was flabbergasted and thought, "Well this is one of the more hopeful songs I have ever written, and he just turned it into a depressing song".
Not to turn it into something out of a depressing film, "It's a Wonderful Life" without the happy ending.
Addams' recounting of tale after tale of violence provides a depressing view of immigrant women's lives at the turn of the century.
