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(To be added to the Schizophrenia research stub)

Schizophrenia is a psychotic disorder that is recognized by the DSM-5. The diagnostic criteria for schizophrenia is outlined in the Diagnostic and Statistical Manual of Mental Disorders- Fifth Edition (DSM-5).

Two (or more of the following), present for a significant portion of a 1-month period. At least one of these must be (1), (2), or (3).

1.    Delusions

2.    Hallucinations

3.    Disorganized speech

4.    Grossly disorganized or catatonic behavior

5.    Negative symptoms

A.  Level of functioning in one or more major areas (work, interpersonal relations, or self-care) is markedly below the level achieved prior to the onset

B.   Continuous signs of the disturbance for at least 6 months

C.   Symptoms are not due to another mental health disorder

D.  Disturbances are not due to substances

E.   If there is a history of Autism Spectrum Disorder or another communication disorder, a diagnosis of schizophrenia is only made if prominent delusions, hallucinations, are also present for at least one month.

Schizophrenia has a prevalence rate of 0.3-0.7% (APA, 2013), however the likelihood that someone will be diagnosed with schizophrenia may be indicative of their life experiences and exposures.

RESEARCH

Research is at the forefront of treatment for Schizophrenia. Many studies have evaluated pregnant mothers and their experiences during pregnancy. Certain complications during pregnancy may increase the likelihood for mothers to give birth to children with mental health disorders (Parnas et al., 1982). Pregnant mothers who are exposed to teratogens during their pregnancy may be more likely to give birth to children that will receive a schizophrenia diagnosis. These include Rubella, Influenza, and Toxoplasma Gondii. For example, children who are exposed to the Rubella virus in utero are 20% more likely to be diagnosed with schizophrenia or another psychotic disorder (Brown et al., 2001). The timing of the exposure to the influenza virus is still under debate, as some studies suggest that mothers who are exposed to influenza in the first trimester are seven times more likely to have children with schizophrenia, but there is no increased risk during the second and third trimesters (Brown et al., 2004). However, other studies suggest that the second trimester exposure to influenza is attributed to a high risk of schizophrenia among offspring.

Children who are exposed to the parasite Toxoplasma Gondii are two times more likely to be diagnosed with schizophrenia (Brown et al., 2005), and can be predicted as early as one week of life among newborns (Mortensen et al., 2007). Among mothers who may not have experienced symptoms of Rubella or Toxoplasma Gondii, the number of antibodies for these infections, if elevated during pregnancy, is associated to a higher probability that their child will have schizophrenia (Buka et al., 2001). Elevated antibodies of cytomegalovirus, herpes, and HPV were also found to be predictors as well (Buka et al., 2001).

One hypothesis for these connections is that these infections stimulate the development of cytokines, which lead to the inflammation of microglia and astroglia in the brain (Patterson, 2008). Microglia are small cells composed of glia. These cells act as a clean-up system, and remove dead cells. Astroglia are star-shaped cells composed of glia that have extensions in all directions. They receive and monitor the activity of nearby neurons and help relay information. (Breedlove & Watson, 2018). When these become inflamed, they produce nitric oxide and amino acids, contributing to neuronal death. This results in differential brain development starting in utero. Therefore, these changes affect the way the brain forms and therefore further develops and functions.

Several studies have evaluated the environmental risks associated with schizophrenia diagnosis. Those who live in urban areas are at a greater risk of diagnosis (Marcelis et al., 1999). Although environmental factors may increase the risk, encouraging and supportive communities may decrease the likelihood of schizophrenia. This belongingness allows for individuals to have a support system which decreases the likelihood that they will be isolated, which may be a contributing factor to the urban areas that have greater prevalence rates of schizophrenia (Allardyce et al., 2005). Resiliency factors are present among many different mental health disorders. Having a community and a sense of belonging may help protect against a schizophrenia diagnosis. However, epigenetics play a role in the diagnosis of schizophrenia as well. In other words, environmental factors are only one piece of the puzzle.

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Arlington, VA: Author.

Breedlove, S. M., & Watson, N. V. Behavioral Neuroscience ''Eighth Edition. Oxford University Press.'' 2018.

Brown AS, Begg MD, Gravenstein S, Schaefer CA, Wyatt RJ, Bresnahan MA, Babulas V, Susser E. Serologic evidence for prenatal influenza in the etiology of schizophrenia. Arch Gen Psychiatry 2004;61:774–780. [PubMed: 15289276]

Brown, AS.; Bresnahan, M.; Susser, ES.; Sadock, BJ.; Sadock, VA. Comprehensive Textbook of Psychiatry. Lippincott, Williams, Wilkins; Baltimore,MD: 2005. Schizophrenia: Environmental epidemiology; p. 1371-1380.

Brown AS, Cohen P, Harkavy-Friedman J, Babulas V, Malaspina D, Gorman JM, Susser ES. A.E. Bennett Research Award. Prenatal rubella, premorbid abnormalities, and adult schizophrenia. Biol Psychiatry 2001;49:473–486. [PubMed: 11257233]

S.L. Buka, M.T. Tsuang, E.F. Torrey, M.A. Klebanoff, D.Bernstein, R.H. YolkenMaternal infections and subsequent psychosis among offspring. Arch. Gen. Psychiatr., 58 (2001), pp. 1032-1037’

Allardyce J, Gilmour H, Atkinson J, Rapson T, Bishop J, McCreadie RG. Social fragmentation, deprivation and urbanicity: relation to first-admission rates for psychoses. Br J Psychiatry 2005;187:401–406. [PubMed: 16260813]

Marcelis M, Takei N, van Os J. Urbanization and risk for schizophrenia: does the effect operate before or around the time of illness onset? Psychol Med 1999;29:1197–1203. [PubMed: 10576311]

Mortensen PB, Pedersen CB, Westergaard T, Wohlfahrt J, Ewald H, Mors O, Andersen PK, Melbye M. Effects of family history and place and season of birth on the risk of schizophrenia. N Engl J Med 1999;340:603–608. [PubMed: 10029644]

Patterson PH. Immune involvement in schizophrenia and autism: Etiology, pathology and animal models. Behav Brain Res. 2008

Parnas, J., Schulsinger, F., Teasdale, TW., Schilsinger H., Feldman, PM., Mednick SA. Perinatal Complications and Clinical Outcome Within the Schizophrenia Spectrum. British Journal of Psychiatry 1982; 140:416-420.