Schizophrenia risk factors: what NIMH says raises the chance

What schizophrenia is

Schizophrenia is a serious mental illness that affects how a person thinks, feels and behaves. People with schizophrenia may appear to have lost touch with reality, which can be distressing for them and for their family and friends (NIMH) (NIMH). The symptoms can make usual, everyday activities hard, but effective treatments are available, and treatment can help people stay in school, keep a job, live independently and enjoy personal relationships (NIMH).

Schizophrenia is not dissociative identity disorder (once called multiple personality disorder or split personality), even though some symptoms may seem similar on the surface (NIMH). There is no score or calculator on this page; the factors below are the ones NIMH and MedlinePlus name.

Who is more likely to develop schizophrenia

NIMH says several factors may contribute to a person's risk of developing schizophrenia (NIMH). MedlinePlus adds that no one is sure what causes it, and that genes, environment and brain chemistry may play a role (MedlinePlus).

• Genes and family history. Schizophrenia sometimes runs in families. Having a family member with schizophrenia does not mean other members will have it too. Studies suggest that many different genes may raise the chance, and that no single gene causes it by itself (NIMH).
• Environment and life experiences. A combination of genetic factors and a person's surroundings and life experiences may play a role. These may include poverty, stressful or dangerous surroundings, and exposure to viruses or nutritional problems before birth (NIMH).
• Brain structure and function. People with schizophrenia may be more likely to have subtle differences in the size of certain brain areas and in the connections between them. Some of these differences may develop before birth (NIMH).

When it usually starts

People are usually diagnosed between the ages of 16 and 30, after the first episode of psychosis (NIMH). Men often develop symptoms at a younger age than women, and people usually do not get schizophrenia after age 45 (MedlinePlus). Schizophrenia is rare in younger children (NIMH).

Gradual changes in thinking, mood and social functioning often appear before the first episode of psychosis, and starting treatment as soon as possible after that first episode is an important step toward recovery (NIMH).

Signs and symptoms

Symptoms differ from person to person but generally fall into three groups (NIMH) (MedlinePlus):

• Psychotic symptoms: hallucinations (seeing, hearing, smelling, tasting or feeling things that are not there; hearing voices is common), delusions (strong beliefs that are not objectively true, such as believing others are trying to hurt you), and thought disorder (trouble organizing thoughts and speech) (NIMH).
• Negative symptoms: loss of motivation, loss of interest or enjoyment in daily activities, pulling away from social life, trouble showing emotions, a dull voice and limited facial expression, and very low energy. These are sometimes mistaken for depression (NIMH).
• Cognitive symptoms: problems with attention, concentration and memory, such as trouble processing information to make decisions or using information right after learning it (NIMH).

Most people with schizophrenia are not violent, and overall they are more likely than people without the illness to be harmed by others. The risk of self-harm and of violence to others is highest when the illness is untreated or occurs together with alcohol or substance misuse (NIMH).

Treatment and getting help

There is no cure, but medicine can help control many of the symptoms, and other treatments help with daily life (MedlinePlus). Treatment options NIMH describes include antipsychotic medication, psychosocial treatments such as cognitive behavioral therapy and skills training, family education and support, coordinated specialty care for people with first episode psychosis, and treatment for drug and alcohol misuse when it is present (NIMH). Do not stop taking a medication without first talking to a health care provider (NIMH).

If you have concerns about your mental health, talk to a primary care provider, who can refer you to a mental health professional such as a psychologist, psychiatrist or clinical social worker (NIMH). To help a friend or relative: help them get treatment and stay in it, remember that their beliefs or hallucinations seem very real to them, and be respectful, supportive and kind without tolerating dangerous or inappropriate behavior (NIMH).

The 988 Lifeline is free and confidential and available 24/7 (988 Lifeline).

Related guides: bipolar disorder risk factors and depression risk factors.

Common questions

Is schizophrenia hereditary?

It sometimes runs in families, but one family member having it does not mean others will. Many genes may each raise the chance; no single gene causes it (NIMH).

At what age does schizophrenia start?

Usually between 16 and 30 (NIMH) (MedlinePlus). Men often develop symptoms younger than women, and it usually does not start after age 45 (MedlinePlus).

Can stress or surroundings play a role?

NIMH says environmental factors that may play a role, together with genes, include poverty and stressful or dangerous surroundings (NIMH).