How Dementia Causes Mental Incapacity and Affects Life Quality

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Tags – Mental Incapacity through Dementia

None of us can probably imagine how upsetting a diagnosis of dementia would be for any member of our family.

However, exactly how this cruel disease manifests itself can vary, as can how much it can affect the mental capacity of the individual concerned. 

Whilst the symptoms of dementia include memory loss, confusion and mood changes, a person with dementia is said to lack mental capacity if unable to make specific decisions at any given time, for themselves.

As someone with dementia declines, they can become more and more unpredictable and less and less able to consider all the facts involved, before making decisions. 

The Mental Capacity Act

However, in England and Wales, the Mental Capacity Act of 2005 protects those who are affected.

This important piece of legislation supports those who lack the mental capacity to make decisions for themselves.

Equally, it goes further and outlines who can – and should – make decisions on their behalf.

As such, the Mental Capacity Act sets out certain rules such as any decision must be made in the best interests of the person who lacks capacity.

Furthermore, for any decision made on their behalf to stand, it has to be proven that the person involved is genuinely incapable of making their own decision. 


The Mental Capacity Act protects the rights of those mentally incapacitated and covers decision-making with regard to someone’s health and social care.

Additionally, it covers decisions regarding their financial and property affairs too.

However, this legislation has no involvement with will-making or voting.

Nor does it cover decisions with regard to marriage or divorce.

Alongside protecting the rights of those incapacitated, the purpose of this Act is to offer help to others involved too. For example, relatives, carers and professionals are offered help in planning for the future. 


Whilst injury, disability and mental illness are conditions that can also give rise to mental incapacity, those suffering with dementia are sometimes more difficult to pinpoint.

The onset of dementia can sometimes be missed as the elderly, most often affected, sometimes live alone or decline slowly.

Symptoms, too, can be confused with those of aging, often delaying a diagnosis. 

Changing Mental Capacity

The mental capacity of someone diagnosed with dementia can change over time.

For instance, there will be some days when they are lucid and thinking much more clearly than others.

Equally, even the time of day can vary their clarity.

Furthermore, it should be kept in mind that some decisions rely on less information than others.

As such, an individual who suffers with dementia may well be able to make some decisions on day to day matters or those which require less consideration.

Therefore, mental incapacity may not be the case all of the time.

To learn more, get in touch with us today.

In the meantime, please check our Court of Protection services.