Collocations for unhappiness - noun

deep, great
general, widespread (esp. BrE)
personal
marital

express
cause, lead to
Bottling up your anger can only lead to unhappiness.

unhappiness about
He expressed his unhappiness about the arrangements.

unhappiness at
the great unhappiness she felt at having to leave the town

unhappiness with
his deep unhappiness with the situation

a cause of unhappiness