A typical clinical course of dementia involves frequent and noticeable forgetfulness. The irritability of the older person is caused by recognizing that there is a problem with his memory and that he cannot explain it. The forgetfulness may involve the loss of objects or difficulty operating commonly used appliances. As memory loss worsens, a patient may start getting lost even in places with which he is familiar.
There will be a noticeable decline in the performance of his work and he may get into conflicts with the people he works with. In the moderate stages, behavioral problems set in. He may have delusions (false beliefs which is thought to be true), commonly about being robbed or concerns of being harmed. He may accuse his spouse of infidelity. Some patients manifest with disinhibition, suddenly cursing people or walking around naked. Others develop hallucinations, both verbal and visual. They may react by being physically aggressive.
Older patients may also become extremely depressed. Oftentimes, it is difficult to tell apart dementia with depression from depression alone because both may appear almost similar. In severe stages, a patient may become withdrawn, eventually becoming chair- or bedbound because of the lack of physical exertion. Basic functions like eating, toileting, grooming, and transferring from one place to another are affected and the older patient may become completely dependent. Problems like infections and pressure ulcers appear because of being bedridden.