Is Mental Illness Genetic? What the Research Says

Mental illness affects how people behave, think, and feel, which can impact many areas of a person's life, including their ability to work, cope with challenges, and relate to others. If you have a family member with a mental illness, you may wonder whether mental illness is genetic and about your own risk of developing a mental health condition. 

This article explores whether mental illness is genetic and the different factors that affect your overall risk of developing a mental disorder.

Is Mental Illness Genetic?

The exact causes of mental illness are not fully understood, but genetics appear to be one piece of the puzzle. Researchers have long noted that certain conditions tend to run families, partly because of genetics, but also because of environmental factors such as shared upbringing.

However, genes alone are not responsible for causing mental illness. And no single gene variant could determine with certainty that a person will have a mental illness.

According to the Centers for Disease Control and Prevention (CDC), mental illness does not have a single cause. Instead, it is often influenced by several factors, including:

• Alcohol or drug use
• Biological factors and abnormalities in the brain
• Experiencing chronic medical conditions
• Social isolation and loneliness
• Traumatic or adverse life experiences

Research on the Genetics of Mental Illness

In one study published in The Lancet, scientists found that certain genetic glitches were associated with five disorders, suggesting a shared underlying genetic vulnerability.

The five disorders are:

1. Autism
2. Attention deficit hyperactivity disorder (ADHD)
3. Bipolar disorder
4. Major depression
5. Schizophrenia
   

This part of the brain's circuitry is linked to several essential mental functions, such as attention, thinking, memory, and emotion. Disrupted neurotransmission can result in problems often associated with different mental health conditions.

While such findings are significant, researchers caution that these genetic variations account for only a small portion of the potential risk for mental illness. Other factors also play a part. Environmental factors often interact with genetic predispositions to increase a person's risk.

Such findings may play an essential role in the future treatment of mental health conditions. Rather than looking primarily at symptoms to diagnose a condition, mental health professionals may one day be able to look at the underlying biology of the condition. This may lead to the development of new treatments that are based on a disease's biology and not the symptoms that they have.

Impact of a Family History of Mental Illness 

Currently, no genetic tests can determine if you have specific genes or gene combinations that might make you more vulnerable to a specific mental disorder. Instead, looking at your family history may offer clues about your possible risk. 

Some mental disorders tend to run in families, so if you have a close relative with a condition, it might mean that your risk is higher.

However, having a family member with a disorder doesn't necessarily mean that you will also develop the condition. 

What's Your Risk of Inheriting a Mental Illness?

Determining your own specific risk is complicated, and estimates vary for different conditions.

Studies that estimate the relative risk of developing different conditions suggest the following:

Schizophrenia Risk

Below lists the following circumstances and the percent risk (the likelihood of you developing the condition if your circumstance matches what's listed):

• If one of your parents has schizophrenia: 6%
• If both of your parents have schizophrenia: 45%
• If your sibling has schizophrenia: 9%
• If your identical twin has schizophrenia: 40% to 50%
• If your non-identical twin has schizophrenia: 17%
• If an aunt, uncle, or grandparent has schizophrenia: 3%

Risk for Bipolar Disorder

Below lists the following circumstances and the percent risk (the likelihood of you developing the condition if your circumstance matches what's listed):

• If one of your parents has bipolar disorder: 5%
• If both of your parents have bipolar disorder: 40%
• If your sibling has bipolar disorder: 5%
• If your identical twin has bipolar disorder: 40% to 70%
• If your non-identical twin has bipolar disorder: 20%
• If an aunt, uncle, or grandparent has bipolar disorder: 5%

However, these are just estimates. More research is needed to better understand genetic risks and other factors that might play a role. The lifetime risk of bipolar disorder or schizophrenia is 1 in 100 (or 1%).

Other conditions, including anxiety and depression, are also tied to genetics, but the inheritance patterns are less clear. Some estimates suggest that if you have a first-degree relative with depression, your risk of developing the condition is around two to three times higher.

How to Reduce Your Risk of Mental Illness

While there is nothing you can do to change non-modifiable risk factors such as genetics, you can take steps to care for your mental health. Even if you are at a higher risk of developing mental illness, taking care of your well-being, watching for early symptoms, and seeking help when you need it can ensure that you have the care and resources to live your best life.

Protect Your Sleep

Sleep and mental health have a complex relationship. Many mental health conditions can cause problems with sleep, but it is also believed that poor sleep can contribute to the onset of mental illness.

Research has also shown that people with mental health conditions such as schizophrenia, bipolar disorder, and depression experience sleep disturbances at a higher rate than people without these conditions.

Stay Physically Active

Exercise has well-documented physical health benefits, but it can also improve mental health. People who exercise regularly report feeling more energetic, happier, and less anxious than those who don't. Some evidence also suggests that exercise can play an important role in the prevention and treatment of certain mental health conditions, including anxiety and depression.

There are a number of ways that exercise can improve mental health, including by:

• Reducing stress and anxiety
• Boosting mood and self-esteem
• Improving sleep
• Increasing social interaction and feelings of connectedness
• Enhancing cognitive function

You don't have to run a marathon or lift weights to reap the benefits of exercise—even moderate activity, such as walking, can have positive effects.

Eat a Healthy Diet

What you eat can affect your mental health. A healthy diet includes plenty of fruits, vegetables, and whole grains, and limits processed foods, saturated fats, and refined sugars. It also includes whole food sources of proteins, such as legumes, nuts and seeds, grass-fed, pasture-raised organic beef (if any red meat all) and dairy, and pasture-raised organic poultry and eggs.

There is some evidence that certain nutrients, such as omega-3 fatty acids, may be particularly beneficial for mental health. Omega-3 fatty acids are found in fish such as salmon and tuna, as well as in nuts and seeds.

Cultivate a Strong Support System

Having a strong social support system of family and friends is crucial for maintaining good mental health. A supportive network can provide essential emotional and practical assistance, and can help you cope with life's stresses and challenges.

One way to build a robust support system is to get involved in your community. Connecting with others with similar interests or experiences can help you feel less alone and more connected. There are many ways to get involved in your community, such as through volunteering, joining a club or organization or participating in local events.

Manage Your Stress

Stress is a part of life. However, it can sometimes become overwhelming or chronic. When stress is constant or severe, it can take a toll on mental and physical health.

There are many ways to manage stress, such as exercise, relaxation techniques, and positive thinking. Finding what works for you is important—what works for one person may not work for another.

Some stress management techniques that may help include:

• Exercise
• Meditation
• Deep breathing
• Yoga
• Tai chi
• Getting enough sleep
• Spending time in nature
• Connecting with friends and family
• Hobbies and activities that bring joy

Limit Alcohol and Avoid Substance Use

Drinking too much alcohol or using drugs can worsen mental health problems and make them harder to treat. If you are struggling with a mental health problem, avoiding drugs and alcohol is important for protecting your mental well-being.

If you drink alcohol, it is essential to do so in moderation. For healthy adults, that means up to one drink a day for women and two drinks a day for men.

If you are taking medication for a mental health condition, alcohol can interfere with its effectiveness and may cause negative side effects. It's important to talk to your doctor about your concerns about drinking alcohol while taking medication.

Get Help If You Need It

If you are struggling with a mental health problem, don't hesitate to seek professional help. A mental health professional can provide support, guidance, and treatment. They can diagnose your condition, recommend treatments, and help you develop coping skills that will help you better manage your condition.

A Word From Verywell

While genetics do appear to influence the risk of developing mental illness, the causes of mental health conditions are complex. Genes account for some risk, but factors such as adverse life events, stress, substance use, chronic medical conditions, and biological factors also play a significant role.

Combinations of genetic factors may elevate risk, and inherited characteristics may also influence how a person responds to different environmental stressors. Recognizing your risk, watching for signs of problems, protecting your mental health, and getting help when you need it can help ensure your well-being and improve outcomes.