noun / verb
relapse
REE-laps/rilˈæps/
A return to a previous harmful condition or behavior after improvement.
The adult suffers a relapse, returning to the couch with a fever after improving.

Etymology
The underlying image is slipping backward. Applied to health or behavior, it describes losing an improvement and falling back into a former bad condition or practice.
In context
ninety percent improve after a year they do relapse so after a few years they sometimes relapse
More examples
- He relapsed into heavy drinking after several months of sobriety.
- The infection seemed gone, but a relapse required further treatment.
- Regular support helps her avoid relapsing into harmful habits.
Forms
relapse · relapses · relapsed · relapsing
Similar words
- recurrence
- Means something happens again, without necessarily following improvement.
- backslide
- Emphasizes returning to bad habits rather than renewed illness.
- setback
- Interrupts progress without necessarily restoring a previous harmful condition.