A method for treating radiotherapy - or chemotherapy - induced cognitive or emotional impairment by topically administering a cannabinoid. The cannabinoid is topically administered to an area of the face of the subject not including the palpebral part of the eye or to the back of the neck. To meet this need, a method for treating radiotherapy- or chemotherapy - associated cognitive or emotional impairment is provided. The method includes topically administering to a subject an effective amount of a composition containing a cannabinoid.