Does mental illness run in families?

Sometimes there are a few people in a family who have the same mental illness. Other times only one person in the family has a mental illness. This page looks at whether mental illness runs in families.

Overview

  • Some research suggests that mental illness can run in families.
  • We do not fully understand what causes mental illness, or why it can be passed on in family members.
  • Mental illness may be passed on for different reasons, not just genes.
  • Even though mental illness may run in families, having a family member with a mental illness doesn’t mean that you or a family member is going to become unwell.
  • There are things you can do to look after your mental health if you are worried about mental illness in your family.

About

If someone in your family has a mental illness, you might be worried about developing the condition as well. If you have a mental illness you might be worried that your children or siblings will develop a mental illness. Most people with a mental illness do not have relatives with the same illness. But research does suggest that mental illness can run in families.

The table below shows the chances of schizophrenia or bipolar disorder being passed down through family members. These numbers are based on recent studies. But different studies can show different numbers.

  Schizophrenia Bipolar
Lifetime chance (the chance of someone in the general population developing the condition during their lifetime) 1 in 100 Bipolar
If one of your biological parents has the condition 13 in 100 2-30 in 100
If both of your biological parents have the condition 45 in 100 15 in 100
If your brother or sister has the condition 9 in 100

50 in 100

 

If your identical twin has the condition 40-50 in 100 40 - 70 in 100
If your non-identical twin has the condition 10-15 in 100 20  in 100
If a second degree relative has the condition (for example, your aunt, uncle or grandparent) 3 in 100 5 in 100

It seems that different mental health conditions, such as schizoaffective disorder and major depression, can run in the same family. There is less evidence to show that other mental health conditions run in families.

You should remember that the chance of not developing a mental illness is much greater than the chance of developing one. This is true even if you have a relative with a mental illness.

You could look at the figures in the table the other way round. You can then see that the chance of someone not developing bipolar disorder is around 97 out of 100. If someone has one parent with bipolar disorder, the chance of not developing the condition is 85 out of 100.

What causes mental illness to run in families?

We do not fully understand what causes mental illness. Or why it can be passed on in families. When a condition is passed on in families through genes, it is called ‘hereditary’. As the table above shows, the chances of developing a mental illness could depend on you and your relatives’ genes. It does seem that mental illness can be hereditary. But we do not fully understand how this works. Mental illness may be passed on to family members for different reasons, not just genes. 

Environmental factors, like loneliness or a stressful life event, can cause mental illness. If you have a family history of mental illness you have a higher chance of developing mental illness in these situations. But having a higher chance of developing a mental illness doesn’t mean that you will develop one. People with no family history of mental illness can develop a mental illness too. There are different ways of looking after your mental health, which are explained more below. 

 

Considerations when starting a family

If you have a mental illness, and you’re thinking of starting a family, you could talk to a professional genetics counsellor. They can give specialist advice and information to people who have relatives with certain health conditions. Your GP or psychiatrist may be able to refer you to a service that does genetic counselling.

If you are thinking about adopting a child who has a family history of mental illness, you might want to speak to a genetics counsellor too.

 

What can I do to reducing the risk?

Mental illness may run in families, but it doesn’t mean that you or someone in your family will become unwell.

If you have a family history of mental illness it can still help to take good care of your mental health. There are things you can do to look after your mental health. Below are some steps you can take.

Having a healthy diet

Eating a healthy, balanced diet is good for your mental and physical health. If you have a limited diet, or eat a lot of unhealthy food, it can make your mental health worse.

Eating healthily can make you less likely to become unwell, and it can help you stay at a healthy body weight. Some mental illnesses can get worse if you don’t have certain nutrients in your diet. For example, a low level of vitamin B is linked to depression.

Getting regular exercise

Moderate exercise can help to improve your mood. It can also help you to feel better about yourself.

Getting enough sleep

Problems with sleep can affect how you feel physically and mentally. In turn, how you feel physically and mentally can also affect how you sleep. If you regularly have problems sleeping, then you should talk to your GP.

Talking to someone about your problems

Talking to people about any problems you have can be useful. There are different ways that you can offload or chat to someone about how you’re feeling. Some emotional support services offer telephone, email, or instant messaging chat.

Stress

Try not to get too stressed. A lot of things in life can cause stress, which can impact your mental health. Sometimes stress cannot be avoided. But you may be able to use coping techniques to limit the effects of stress.

Drug use

Using alcohol or drugs can cause mental illness in some people. Some people have told us it caused problems with getting the right treatment when they were unwell.

If you find you use alcohol or drugs to deal with problems or stress, then you could try some of the options above instead.

Speak to your GP if you are worried that you have signs of mental illness. Or if you are worried about your drug or alcohol use.

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