Wiktionary
n. A series of thoughts or actions which feeds back into itself, causing a situation to become progressively worse. It is worse than a vicious circle, which is self-sustaining in its current state.
Usage examples of "downward spiral".
And it kept right on falling with a sort of twist to it, spinning me into a downward spiral which threw me off to the left of the trail.
While most of the candidate globes tried to keep on course-doggedly continuing their downward spiral, despite collisions and chaos waves-^-a small minority were attempting to flee, like Streaker.
The downward spiral was far more subtle than the Dawn Age pessimism of Karl Marx or Han Su, and only vaguely related to the insights of Mancur Olson.
Her first shot missed, but the second caught the lead demon in the shoulder, sending him into a downward spiral.
If so, then the world is indeed on a downward spiral into the Abyss.
But as the 80's and 45's moved toward extinction in their coevolutionary downward spiral, a mutant of the 45's appeared.
Surely we ought to have followed a radio beacon in an upward spiral, as we did in a downward spiral on landing?
By the time Keff and Carialle landed, the system was disintegrating dangerously, and Ozran society was in a downward spiral.