SCHIZOPHRENIA AND ITS BIOLOGICAL BASIS

UĞUR İŞBİTİREN1890151

PSYC 374

OUTLINE

History & General Characteristics of Schizophrenia

Brief Overview of Symptoms

Biological Explanations of Schizophrenia

Genetic Explanation

Neurochemical Explanation

Brain Abnormalities

Other Biological Explanations

Conlusion

HISTORY

First identifed by German Psychiatrist Emil Kraepelin as ‘‘Dementia Praecox’’

Kraepelin mainly underlined mental detoriation, extreme suspicion in addition to hallucinations, withdrawn behavior, incapacity for regular works

Swiss Psychiatrist Eugen Bleuler named it as ‘‘Schizophrenia’’ with today’s diagnostic criteria

Butcher, Mineka & Hooley, 2011

GENERAL CHARACTERISTICS

Type of psychotic disorders

Loss of contact with reality

Bizarre behaviours

Most interesting and most puzzling

May be very devastative and disruptive

Passer et al, 2009

SYMPTOMS

Positive Symptoms (DSM-IV-TR) Delusions Hallucinations Disorganized speech Grossly disorganized or catatonic behavior

At least for one month, two or more of the above must be present.

Barlow & Durand, 2012

SYMPTOMS (cont’d)

Negative Symptoms (DSM-IV-TR) Avolition (little interest for daily activities) Alogia (little content in communication) Anhedonia (lack of pleasure from activities) Affective Flattening (lack of emotions displayed)

Barlow & Durand, 2012

BIOLOGICAL EXPLANATIONS OF SCHIZOPHRENIA

Genetic Predisposition One of the strongest evidence (Carlson, 2010)

Identical twins, 48% chance to have Schizophrenia (Butcher, Mineka & Hooley, 2011)

Responsible genes are unknown, found that interaction of several genes plays role (Kalat, 2009).

http://www.schizophrenia.com/research/hereditygen.htm

BIOLOGICAL EXPLANATIONS (cont’d)

Dopamine Hypothesis The neurochemical perspective Excessive activity in Dopamine pathways associated with

symptoms Challenged and adjusted several times, yet still, the most

important neurochemical explanation (Comer, 2014). Supported by the fact that substances associated with

psychotic effects increase the dopamine release in the brain

Emergence of Antipsychotic Drugs which affect Dopamine release (Kalat, 2009)

BIOLOGICAL EXPLANATIONS (cont’d)

Brain Abnormalities Supported by lots of studies People with Schizophrenia have larger brain ventricles (spaces

contain cerebrospinal fluid) (Jackobi & Winkler, 1927). Lesser or deficient activity in Dorsolateral Prefrontal Cortex

(Berman & Weinberger, 1990). Smaller Thalamus size (Shenton et al., 2001). Hippocampus cell abnormalities (Arnold, 2000). Also abnormalities with Basal Ganglia, Limbic System,

Wernicke’ s Area; reduction in volume of Grey Matter, as a result of several studies.

Obvious correlation yet no cause-effect relationship!Barlow & Durand, 2012; Butcher, Mineka & Hooley,

2011

BRAIN IMAGES OF SCHIZOPHRENIC PATIENTS

http://www.treatmentadvocacycenter.org/component/content/article/325

http://www.pnas.org/content/98/20/11650/F3.expansion.html

OTHER BIOLOGICAL EXPLANATIONS

Glutamate Hypothesis Lower release of neurotransmitter Glutomate seems to be

related with positive and negative symptoms of Schizophrenia, based on studies with PCP and Ketamine Substance

Relatively new hypothesis, being investigated The Neurodevelopmental Hypothesis

Based on the idea that prenatal and neonatal problems (viral, poor nutrion, birth complications etc.) may cause brain abnormalities which can lead to development of Schizophrenia (Ballon, Dean & Cadenhead, 2007).

Butcher, Mineka & Hooley, 2011; Kalat, 2009)

CONCLUSION

Lots of strong evidences that support various biological explanations.

Majority of them can only give correlations, not cause-effect relations!

Diathesis-Stress Model underlines the relationship between obvious genetic, structural and environmental aspects such as stress, regarding the development of Schizophrenia (Butcher, Mineka & Hooley, 2011).

REFERENCES Barlow, D. H. & Durand, V. M. (2012). Abnormal

Psychology: An Integrative Approach. Belmont: Wadsworth. Butcher, J. N., Mineka, S. & Hooley, J. M. (2011). Abnormal

Psychology: Core Concepts. Boston: Allyn & Bacon Carlson, N. R. (2010). Physiology of Behaviour. Boston:

Allyn & Bacon Comer, R. J. (2014). Fundamentals of Abnormal Psychology.

New York: Worth Publishers. Kalat, J. W. (2009). Biological Psychology. Belmont:

Wadsworth. Passer, M., Smith, R., Holt, N., Bremner, A., Sutherland, E. &

Vliek, M. (2009). Psychology: The Science of Mind and Behaviour. Berkshire: McGraw - Hill.