What causes mental illness?

It’s not known exactly why people develop mental health disorders – it’s a riddle researchers the world over are still trying to solve. Enough progress has been made to know it’s highly unlikely the answer will be a single cause.

It’s worth knowing that if you are experiencing a mental health disorder, you have an illness – you do not have a character fault, weakness or something inherently 'wrong' with you.

Mental health and mental health disorders are thought to be caused by a number of interacting things, just as health and illness in general are, too. An episode of illness seems to happen in someone who is biologically and psychologically at risk, and undergoing social or environmental upset.

Risk factors for developing a mental illness

Biological

Many years of research have shown your chance of experiencing a mental illness - such as schizophrenia, bipolar mood disorder (manic depressive illness), childhood depression, autism and attention deficit hyperactivity disorder – is at least partly determined by your genes. 

Researchers are hunting genes that may be linked to mental disorders because they are likely to be a vital key to working out what goes wrong in the brains of people who experience mental illness. So far they have found that your genetic risk is not due to a single faulty gene, but to the joint effects of many genes acting together with environmental factors. In essence, researchers now tend to believe that even if we do have a gene that makes us vulnerable to a mental illness, if we are brought up, and continue to live in, a healthy and supportive environment, we may not become ill.

Changes in brain structure and function

The way your brain is structured can affect the way it works, affecting your feelings, thoughts and behaviour. Alcohol and drug abuse can alter the production of brain chemicals, which can make you vulnerable to mental illness.

Environment

Your social environment, including your relationships, ethnicity, family life, school experiences and social class, is thought to contribute to your mental wellbeing. Any trauma, abuse, neglect, death or other stressful life experience can contribute to, or trigger, mental illness.

Your physical environment – the quality of housing, air quality and building design - can also affect your mental health. Being poor, therefore, is a predictor of mental illness; where there are low levels of education and income, poor housing and inadequate nutrition, there will probably be more feelings of insecurity and hopelessness, and the risk of violence and physical ill-health will increase. This all puts mental health at risk.

Negative thinking

If you are vulnerable to mental illness, constant negative thinking can worsen your condition. Your self-esteem and thinking style is important to keep you in good mental health.