Delirium.
A condition common in older people, as a result of other illnesses or from the adverse effects of medications. The person may become confused and forgetful but unlike Alzheimer's disease, the person with delirium has an altered level of consciousness ie. they do not appear alert.

Depression.
Another condition that is common among older people and often mistaken for Alzheimer's disease is depression. It is usually characterised by severe and prolonged mood changes. It has often been referred to as "pseudo-dementia".

Drug Reactions.
Every drug consumed has an effect on the body. As we age our bodies metabolise drugs differently as to when the body was younger. Therefore older people are more susceptible to adverse drug reactions. Over the counter medications such as panadol, cough medicines, vitamin supplements and herbal medicines can all adversely react with prescription drugs. These reactions may present the same symptoms as seen in Alzheimer's disease, such as short term memory loss, confusion and disorientation.

A person with irreversible dementia may also experience delirium, depression or adverse drug reactions during the course of their dementia. It is therefore crucial to have regular medical assessments to minimise the chance that other treatable conditions are further debilitating the person with an irreversible dementia.