desensitization vs desensitisation

desensitization and desensitisation both are nouns.

Word	Noun	Adjective	Verb	Adverb
desensitization	Yes	No	No	No
desensitisation	Yes	No	No	No

As nouns, desensitization and desensitisation are synonyms defined as:

desensitization and desensitisation: the process of reducing sensitivity

desensitization (noun)	desensitisation (noun)
the process of reducing sensitivity	the process of reducing sensitivity