Recurrence
Recurrence is said to occur when a phenomena that has occurred sometimes before, occurs again. Any phenomena, event or incident that has a natural tendency to take place again and again over a period of time is qualifies as a recurring phenomena. The phenomena which recurs are usually predictive and can be predicted over the time. For example, Kalbaishaki or northeasters are rainfall pattern that is recurring and usually reoccur after a specific time span that is during the monsoons on the Indian subcontinent, hence is predictable and precautionary measures can be taken.
Similarly there are mental disorders which have the tendency to reoccur in the clinical picture of an individual over a period of time. The recurring episodes can occur in case of bipolar depression, cyclothymia, panic disorders, phobia etc. The client in between the two episode might have symptoms free spells, which does not ensure cure of the disorder.