Relapse (verb)

1. To fall back into a previous state or condition, particularly a state of illness.
2. To return to a previous bad habit or behavior after having made progress in overcoming it.

Origin:

From the latin relapsus, from re- meaning "again" and lapsus meaning "to slip or fall".

Examples:

1. The patient experienced a relapse of the disease after a period of remission.
2. After months of sobriety, the recovering alcoholic had a relapse and began drinking again.
3. The economy is in danger of relapse after a period of recovery.
4. The company's profits had a relapse after a period of growth.
5. The patient's symptoms relapsed after discontinuing the treatment.