Perception is the awareness of objects in relation to each other and follows stimulation of peripheral sense organs. Disturbances of perception include hallucinations that is false sensory perceptions not associated with real or external stimuli. Hallucinations often take the form of false auditory perceptions, false perceptions of smell, taste and touch. The older patient who is severely depressed may have frank auditory hallucinations that condemn or encourage self-destructive behaviour. Disturbances in thought content are the most common disturbances of cognition noted in older patients with psychosis.

 The depressed patient often develops beliefs that are inconsistent with objective information obtained from family members about the patients abilities and social resources. Older patients appear less likely to expertise delusional remorse, guilt or persecution. Even if delusions are not obvious, preoccupation is closely associated with obsessional thinking or irresistible intrusion of thoughts into the conscious mind.

 Although the older adult rarely acts on these thoughts into the conscious mind. Although the older adult rarely acts on these thoughts compulsively, the guilt provoking or self-accusing thoughts may occasionally become so difficult to bear that the person considers, attempts or succeeds in committing suicide. Disturbances in thought process accompany disturbances of content. There may be problems with the structure of associations, the speed of associations and the content of thought.

The older adults who is compulsive or has schizophrenia may pathologically repeat the same word or idea in response to a variety of probes as may the patient who has primary degenerative dementia. Some older adults with dementia have circumstantially that is the introduction of many apparently irrelevant details to cover a lack of clarity and memory problems. On other occasions, elderly patients may appear incoherent with no logical connection of their thoughts, or they may produce irrelevant answers. The intrusion of thoughts from previous conversations into a current conversation is a prime example of the disturbance in association found in patients with primary degenerative dementia, such as dementia of Huntington’s disease. However in the absence of dementia even paranoid older adults do not generally show a significant disturbance in the structure of associations.