These conditions, collectively termed chemosensory dysfunctions, are many and varied, and they may trigger a person to complain of an odor than is not present; however, the diagnostic criteria for ORS require the exclusion of any such causes. They include pathology of the right hemisphere of the brain, substance abuse, arteriovenous malformations in the brain, and temporal lobe epilepsy.
A diverse array of conditions, collectively referred to as chemosensory dysfunctions, can cause individuals to perceive odors that are not actually present; nonetheless, the diagnostic standards for ORS require ruling out any such potential causes. These include brain abnormalities in the right hemisphere, substance abuse, cerebral blood vessel malformations, and temporal lobe seizures.