Cyclothymia is a type of

Persistent mood disorders are characterised by persistent mood symptoms which last for more than 2 years but are not severe enough to be labelled as even hypomania or mild depressive episode. If the symptom consists of persistent inability of mood between mild depression and mild elation, the disorder is called as cyclothymia (Ref: a sho textbook of psychiatry, Niraj Ahuja,7th edition, pg no73)