- 21 September 2020
- 6 min read
How to Assess Mental Capacity: A Guide for Newly Qualified Nurses

Dementia Psychiatrist and Founder of Hometouch, Jamie Wilson, discusses why being able to assess mental capacity is such an important clinical skill, and how you can add it to your arsenal.
Topics covered in this article
Why Is It Important To Assess The Mental Capacity?
When Is A Mental Capacity Assessment Required?
Who Can Assess The Mental Capacity Of A Patient?
What Is The Test For Assessing The Mental Capacity Of A Person?
Introduction
If you are a newly qualified nurse, knowing how to assess mental capacity is an important clinical skill.
Mental capacity is the ability of a person to make a specific decision at a required time.
It is regulated under the Mental Capacity Assessment Act (2005), which applies to people above the age of sixteen.
The Act mainly deals with the consent of a person regarding a certain matter at a specific time.
Therefore, the person’s decision-making ability to give consent on a certain matter is both context and time specific.
Why Is It Important To Assess The Mental Capacity?
Firstly, it helps to determine whether or not a person is suffering from some kind of impairment or disturbance in his or her mind.
Secondly, if it becomes apparent that there is some sort of impairment, then mental capacity assessment helps in determining whether this impairment is interfering with a person’s decision-making capacity.
When Is A Mental Capacity Assessment Required?
A mental capacity assessment is required mostly when it is evident that a person doesn’t have the mental capacity to make decisions when needed.
The evidence may be available in the form of an impairment or disturbance in the brain, which would be the reason behind the person not being able to make the decision.

For example, a patient that is acutely confused due to a urinary tract infection, may not be able to consent to a certain type of treatment.
In most clinical scenarios, a mental capacity assessment is required when a patient has to give his or her consent to undergo treatment, but it is observed that the patient is not able to make the decision due to some reason.
Sometimes, a person may make an “unwise” decision, but the law protects this person.
Just because you may not agree with the decision, it does not mean the person lacks capacity.
Who Can Assess The Mental Capacity Of A Patient?
The law has not laid down any restrictions regarding who can assess the mental capacity of another individual.
However, healthcare professionals including psychologists, doctors, nurses, are most likely to carry out this assessment, since they are experienced in this area and also should understand what capacity in regard to.
Legal Protection And Consent
Nurses and other health care workers need legal protection from a patient; in most cases, legal protection comes through the consent of the patient.
To explain this, a patient giving a blood sample to the nurse is giving the nurse appropriate informed consent.
That means the patient knows clearly why and what the blood test would involve.
If you are a nurse, and want to improve your skills in assessing the mental capacity of patients, then there are a few things that you need to do.
---------- ---------- ---------- ---------- ----------
What do YOU think?
Let me know your thoughts in the Comments & click Like!
---------- ---------- ---------- ---------- ----------
Training
Firstly, you will have to take training on the Mental Capacity Act (MCA) so that you understand the basics.
Since a nurse is someone who the patient is directly linked with when a decision needs to be made, some basic familiarity with the MCA is crucial.
Record Keeping
Even though there is no statutory requirement for record-keeping, under the code of practice nurses are obliged to maintain a record of the patient’s assessments, carry out the mental assessment directly with the patient and work in the best interests of the patient.
What Is The Test For Assessing The Mental Capacity Of A Person?
A two-stage test is used for assessing the mental capacity of a person:
1. Diagnostic Test
2. Functional Test
Diagnostic Test
The first test, known as the ‘diagnostic test’, is used for determining whether or not the person has some impairment or disturbance in the brain that is interfering or hindering the person’s ability to make decisions.
Furthermore, it must be seen whether the impairment or disturbance is of a temporary or permanent nature.
Functional Test
The second test known as the ‘functional test’ is linked with the first test.
When it becomes apparent that the person is suffering from an impairment, at this stage it is determined whether or not that impairment has stopped the person from making a decision at a specific time.
To conduct the functional test, a few factors need to be determined:
● The person is unable to understand the information related to the decision.
● The person can’t remember the information long enough to make the decision.
● The person can’t use the information in the right way to make the decision.
● The person lacks the ability to communicate the decision by any means.
Nurses should understand that patients have to have mental capacity before they can agree to care or treatment.
They cannot give or withhold consent if they lack mental capacity.
Now that you know how to assess the mental capacity of a patient, you will be able to determine whether or not a person lacks the mental capacity to make a decision without any difficulty.
Let me know in the comments your thoughts on assessing mental capacity - let's chat there!
Oh, and please Like this article to let me know you enjoyed it - thank you!
Dementia Specialist
About the author
Dementia Specialist
I’m a Dementia specialist and the founder of Hometouch, set up to improve the quality of home care and proactively help people maintain brain health. I am a passionate advocate of prevention in the world of brain health and am interested in how we can empower carers to improve their patient’s lives, conditions and importantly, delay the onset of cognitive impairment.
Want to get involved in the discussion
Sign In JoinRead something else
My Experience Of Joining The Covid-19 Temporary Register
Following up a previous blog on returning to nursing during the pandemic, Former Nurse, Thijs Mostert, describes the technical hiccups that have further delayed the process.
What Do Interviewers Look For In Child And Adolescent Mental Health Services CAMHS Nurses?
Mental Health Nurse, Rachel, examines which extra skills are required in CAMHS Nursing and gives her advice on how to succeed in your next CAMHS Interview.
How To Change Your Career And Become A Mental Health Nurse
Deputy Ward Manager, Naomi, outlines how she got out of her career rut and requalified to move into Forensic Nursing, and discusses why Mental Health Nursing can be so rewarding.
Latest Jobs
Registered Mental Health Nurse
York, North Yorkshire, England
Appoint Healthcare
Registered Nurse
Durham, Durham, England
Leaders In Care
Registered General Nurse RGN
Henbury, Bristol, City of Bristol, England
Vetro Recruitment
RMN Deputy Ward Manager
Potters Bar, Hertfordshire, England
SYK Recruitment
Registered Mental Health Nurse
Leicester, Leicestershire, England
HCL Workforce
Registered Mental Health Nurse
Gloucester, Gloucestershire, England
Prospero Health & Social Care
See all of our Mental health nurse jobs
1661 jobs currently available