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Ongoing updates of key clinical trial advances and new study data for common conditions.

By Lisa Kuhns, PhD

Published July 14, 2022.


Schizophrenia is a mental illness characterized by impairments in the ability to think clearly, perceive reality, manage emotions, make decisions, and relate to others. It affects 0.25% to 0.64% of the US adult population and can occur at any age. The average age of onset is the late teens to early 20s for men and late 20s and early 30s for women.1

Symptoms include hallucinations, delusions, thought and movement disorder, loss of motivation and interest in daily life, withdrawal from social life, difficulty showing emotions and functioning normally, difficulty processing information and using information immediately after learning it, and difficulty focusing or paying attention.

Most people with schizophrenia are not violent. However, self-harm risk and being violent to others is more likely if the illness goes untreated. Rapid treatment is important for managing the illness and preventing disorder escalation.2


Risk factors for developing schizophrenia include genetics, the environment, and brain structure and function. Schizophrenia can be genetic, but other factors play a role as well. Many genes are involved in schizophrenia development, and no single gene has been associated with schizophrenia in isolation.2-6 However, a person who has schizophrenia in their family is more than 6 times more likely to develop the disorder.7

The environment may also play a role. Environmental factors such as living in poverty, living in stressful or dangerous surroundings, and exposure to viruses or nutritional problems before birth can increase the risk for schizophrenia.8 Additionally, research shows that people with schizophrenia have size differences in certain areas of the brain and connections between brain areas.9 Taking mind-altering drugs during teen years and young adulthood can increase the risk of developing schizophrenia.10 Evidence suggests that smoking marijuana increases psychotic incidence risk and ongoing psychotic experience risk. The risk for developing schizophrenia increases with younger age of marijuana use and the more frequently it is used.1

Screening and Diagnosis

To rule out other causes of psychotic symptoms, clinicians should obtain information about the medical and psychiatric family history, details about pregnancy and early childhood, history of travel, and history of medications and substance abuse.11 A change in personality and a decrease in academic, social, and interpersonal functioning usually occurs in middle to late adolescence, and 1 to 2 years pass between the onset of these symptoms and the first psychiatrist visit.12 The first psychotic episode occurs between the late teenage years and mid-30s.12

Schizophrenia symptoms are categorized into 4 domains: positive, negative, cognitive, and mood symptoms.13 Positive symptoms include hallucinations. Negative symptoms include a decrease in emotional range, speech change, and loss of interest or drive. Cognitive symptoms include neurocognitive deficits. Mood symptoms include seeming cheerful or sad, and patients often have comorbid depression.13

The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria14 for schizophrenia include the significant presence of 2 or more of the following symptoms during a 1-month period (or less if successfully treated). One of the presenting symptoms must be delusions, hallucinations, or disorganized speech:

  • Delusions
  • Hallucinations
  • Disorganized speech
  • Disorganized or catatonic behavior
  • Negative symptoms

Moreover, the criteria also specify the length of time symptoms must be present in order for a diagnosis to be made:

  • If functioning in a major area is not achieved for a significant portion of time since the onset of a disturbance
  • If signs of the disturbance continuously persist for at least 6 months and include at least 1 month of symptoms

Schizoaffective disorder and depressive disorder with psychotic features can be ruled out if no major depressive, manic, or mixed episodes have occurred with the active-phase symptoms or if any mood episodes during the active-phase symptoms are present for a short time during the active and residual periods of the illness. A diagnosis can be made if the disturbance is not due to substance misuse or another medical condition. Finally, if a history of autism spectrum disorder or a communication disorder of childhood-onset is present, a schizophrenia diagnosis is only made if prominent delusions or hallucinations, in addition to other schizophrenia symptoms, are present for at least 1 month.11,14

Treatment and Management

Treatments for schizophrenia include pharmacotherapy and psychosocial interventions with the goals for the patient to have few or stable symptoms, avoid hospitalization, manage their own funds and medications, and be able to work or attend school.11 The American Psychiatric Association (APA) recommends that while assessing patients and determining a treatment plan, the initial patient assessment should include the reason why the individual is presenting for evaluation, the patient’s goals and treatment preference, a review of symptoms and trauma history, an assessment of tobacco and substance use, a psychiatric treatment history, assessment of physical health, assessment of psychosocial and cultural factors, mental status examination, and assessment of suicide and aggressive behavior risk.11 The assessment should also include the symptom severity.11

The APA recommends treatment with an antipsychotic medication and monitoring for effectiveness and adverse effects.11 Patients with schizophrenia whose symptoms have improved with antipsychotic medication should continue to take an antipsychotic medication or the same antipsychotic medication. Individuals with treatment-resistant schizophrenia should be treated with clozapine if the risk for suicide attempts, suicide, or aggressive behavior remains substantial despite other treatments. Patients with acute dystonia associated with antipsychotic therapy should be treated with an anticholinergic medication.11

Psychosocial interventions are essential for people with schizophrenia and include social skill training, cognitive-behavioral therapy, cognitive remediation, and social cognition training.15


Treatment can help people with schizophrenia live healthy lives that are productive and rewarding. A treatment plan developed for the patient will work toward controlling symptoms. Once symptoms are controlled, patients can continue to receive therapies and family support to help with disease management and coping.15


1. Schizophrenia. NAMI: National Alliance on Mental Illness. Accessed June 16, 2022.

2. Schizophrenia. National Institute of Mental Health (NIMH). Updated April 2022. Accessed June 16, 2022.

3. Mostafa M, Elwasify M, Fathy AA, Abdelsalam M. Toll-like receptor 4 gene polymorphisms and susceptibility to schizophrenia: a case-control study. Immunol Invest. Published online July 11, 2022. doi:10.1080/08820139.2022.2093118

4. Guardiola-Ripoll M, Almodóvar-Payá C, Lubeiro A, et al. A functional neuroimaging association study on the interplay between two schizophrenia genome-wide associated genes (CACNA1C and ZNF804A). Eur Arch Psychiatry Clin Neurosci. Published online July 7, 2022. doi:10.1007/s00406-022-01447-z

5. He F, Zhou YM, Qi YJ, et al. Exploration of mutated genes and prediction of potential biomarkers for childhood-onset schizophrenia using an integrated bioinformatic analysis. Front Aging Neurosci. Published online June 16, 2022. doi:10.3389/fnagi.2022.829217

6. Sharypova EB, Drachkova IA, Chadaeva IV, Ponomarenko MP, Savinkova MP. An experimental study of the effects of SNPs in the TATA boxes of the GRIN1, ASCL3 and NOS1 genes on interactions with the TATA-binding protein. Vavilovskii Zhurnal Genet Selektsii. 2022;26(3):227-233. doi:10.18699/VJGB-22-29

7. Chou IJ, Kuo CF, Huang YS, et al. Familial aggregation and heritability of schizophrenia and co-aggregation of psychiatric illnesses in affected families. Schizophr Bull. 2017;43(5):1070-1078. doi:10.1093/schbul/sbw159

8. Brown AS. The environment and susceptibility to schizophrenia. Prog Neurobiol. 2011;93(1):23-58. doi:10.1016/j.pneurobio.2010.09.003

9. Karlsgodt KH, Sun D, Cannon TD. Structural and functional brain abnormalities in schizophrenia. Curr Dir Psychol Sci. 2010;19(4):226-231. doi:10.1177/0963721410377601

10. Khokhar JY, Dwiel LL, Henricks AM, Doucette WT, Green AI. The link between schizophrenia and substance use disorder: A unifying hypothesis. Schizophr Res. 2018;194:78-85. doi:10.1016/j.schres.2017.04.016

11. Keepers GA, Fochtmann LJ, Anzia JM, et al. The American Psychiatric Association practice guideline for the treatment of patients with schizophrenia. Am J Psychiatry. 2020;177(9):868-872. doi:10.1176/appi.ajp.2020.177901

12. Green AI, Drake RE, Brunette MF, Noordsy DL. Schizophrenia and co-occurring substance use disorder. Am J Psychiatry. 2007;164(3):402-408. doi:10.1176/ajp.2007.164.3.402

13. Tamminga CA. Domains of dysfunction in schizophrenia: implications for diagnosis. World Psychiatry. 2008;7(1):34-35. doi:10.1002/j.2051-5545.2008.tb00147.x

14. Substance Abuse and Mental Health Services Administration. Impact of the DSM-IV to DSM-5 changes on the national survey on drug use and health. Substance Abuse and Mental Health Services Administration (US); June 2016.

15. Kern RS, Glynn SM, Horan WP, Marder SR. Psychosocial treatments to promote functional recovery in schizophrenia. Schizophr Bull. 2009;35(2):347-361. doi:10.1093/schbul/sbn177