How do you use cathartic in a sentence?

It's an adjective, used to describe a noun or a gerund.

Examples:

Richard found the effort very cathartic. (noun is 'effort')

Talking to someone about a problem can be cathartic. (gerund is 'talking')

Jane found using a punchbag highly cathartic. (gerund is 'using')

Exercise is often cathartic. (noun is 'exercise'