relapse

To fall back again; to slide or turn back into a former state or practice.

He has improved recently but keeps relapsing into states of utter confusion.

to relapse into a stupor, into vice, or into barbarism

To recur; to worsen, be aggravated (after a period of improvement).

To return to a vice, especially self-harm or alcoholism, failing to maintain abstinence.

relapsed after 5 months of being clean

To slip or slide back physically; to turn back.

You slip your hold and change your side, Relapsing from a necessary guide.

The act or situation of relapsing.

a drug relapse

Alas! from what high hope to what relapse / Unlooked for are we fallen!

An occasion when a person becomes ill again after a period of improvement

One who has relapsed, or fallen back into error; a backslider.