Personality changes and brain tumours

Our brains control every aspect of who we are, what we think and feel. Brain tumours can sometimes cause personality changes such as confusion, anxiety or mood swings.

Read more about these changes and get tips on how to cope if you're affected.

Download our factsheet about personality changes and brain tumours.

What sort of personality changes can brain tumour cause?

While a certain amount of personality change might be experienced due to the natural reaction to diagnosis and treatment, not everyone with a brain tumour will experience personality changes that could be classed as problematic.

If you have or had a brain tumour, you may experience changes to aspects of your personality. Personality changes may include:

Read more about brain tumour side effects.

Why can brain tumours cause personality changes?

Location of the tumour

As a brain tumour grows, it puts pressure on surrounding tissue affecting the function, process or part of the body that is controlled by that area of the brain. Personality changes are most common in people when the tumour is located in their frontal lobe, which controls personality, behaviour and emotions, problem solving and long-term memory. Personality changes can also be caused by a tumour in the pituitary gland which controls hormone levels.

Swelling in the brain

This can result from treatments including surgery, radiotherapy and chemotherapy. Personality changes that have occurred as a direct or indirect result of these treatments usually pass gradually as you recover. Large tumours can have a greater effect as they affect a greater area. However, even a small tumour in a key structure of the brain can have a significant impact.

The impact of the diagnosis and treatment

Personality changes might be experienced as a natural reaction to the diagnosis and treatment. The emotional impact of the diagnosis, undergoing treatment, and the lifestyle changes that are often necessary for a person living with a brain tumour, can affect mood, general persona and can cause a person to become more irritable.

Tips to cope with personality changes

Talk to others

This is something many people find helpful. You may wish to share your feelings with close family, friends, or a counsellor. Your GP may also refer you to a counsellor or psychologist


To help cope with personality change, it is always a good idea to speak to your doctor. They will be able to talk through options available to you such as medication, Steroids help to bring down swelling, which can lessen personality changes that have occurred as a result of swelling. Your doctor may also prescribe medications, such as tranquilisers or anti-depressants to manage anxiety, aggression and depression.

Monitoring others' reactions

If you are living with a brain tumour and are aware, or concerned that you may be acting inappropriately, you may find it helpful to pay close attention to others' reactions and responses. This may help give you an idea of whether the way you are acting is in any way inappropriate.

Will I be aware of the change to my personality?

This varies. Some people are aware of their personality changes, some people aren't, or they may not have full awareness.

Discovering the source of the problem is the first step and a way to evaluate changes in personality is to consult with a neuropsychologist. Neuropsychologists specialise in physical effects of brain disease or injury on mental abilities.

How to help a loved one

It can be very upsetting to see personality changes in someone you love. How to help best will depend on the nature of the personality change and the nature of your relationship, but having patience and understanding can be very supportive.

Below are some other strategies that may be helpful:

  • Finding ways to plan and organise tasks
  • Breaking down tasks into smaller chunks for your loved one could help them do more if they have memory problems
  • If your loved one is showing inappropriate behaviour, try not to show embarrassment or disgust. Instead, try to let them know that their behaviour is not appropriate and give them consistent guidance on how to behave
  • Try to avoid comparing the person now to the 'person they were before' too much, which can be upsetting for both of you
  • Create a calm environment or even remove your loved one from stressful situations if they show signs of aggression

Read more information and advice about caring for someone with a brain tumour.

Get support

If you or a loved one has been diagnosed with a brain tumour, we offer a range of support.

You may also wish to join our friendly and supportive Facebook community.

Relationship Support

We know that a brain tumour diagnosis often impacts the wider family. In our 'Losing Myself' report, 2 in 3 said that they had seen a negative impact on their relationship with their partner, while 72% have had physical intimacy affected. Studies show that it is the personality and cognitive effects of brain tumours that place the most strain on relationships, particularly where they cause behaviour change, but that techniques to support caregivers can make a positive difference.

We have been working in partnership with OnePlusOne - a charity that specialises in relationship building - to investigate the experiences of those affected by a brain tumour and possible support needs. If you would like to contribute to our work on developing bespoke relationship support for those affected by a brain tumour, please contact the Information and Support team on 0808 800 0004 or email us at – we would love to hear from you.

In the meantime, you might be interested in Click – an online resource that's been developed by OnePlusOne to provide general relationship support and help you strengthen your relationships. It features a professional-led listening room, moderated community posts, evidence-based articles, goal-setting, quizzes, and personalised recommendations to help you improve and maintain the quality of your relationships.

Download our factsheet about personality changes and brain tumours

Page last reviewed: 04/2016
Next review date: 04/2019

logo for the information standard certification logo for the helplines partnership

If you have further questions, need to clarify any of the information on this page, or want to find out more about research and clinical trials, please contact our team:

Information and Support line

0808 800 0004 (free from landlines and mobiles)

Phone lines open Mon-Fri, 09:00-17:00

You can also join our active online community on Facebook - find out more about our groups.

We promise to keep your data safe and you can unsubscribe at any time in the future. More information is in our Privacy Policy.