
History & General Characteristics of Schizophrenia

Brief Overview of Symptoms

Biological Explanations of Schizophrenia
 Genetic Explanation
 Neurochemical Explanation
 Brain Abnormalities
 Other Biological Explanations

Conlusion

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suspicion in addition to hallucinations, withdrawn behavior,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
 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

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

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

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

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)

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
http://www.treatmentadvocacycenter.org/component/content/article/325
http://www.pnas.org/content/98/20/11650/F3.expansion.html

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)

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).

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.