Etiology of schizophrenia. taniya thomas. msc 1st
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Transcript of Etiology of schizophrenia. taniya thomas. msc 1st
F20-F29 ; ETIOLOGYBIOLGICAL THEORIESLEARNING THEORIESCOGNITIVE THEORIES
TANIYA THOMAS11699014
1ST MSC CLINICAL PSYCHOLOGY
DISCOVER THROUGH…Schizophrenia , an introduction
Risk factorsBiological etiology and theories
Learning theoriesCognitive theoriesSummary and conclusion
IDENTIFY
Dementia precox (1899)
Differentiated from manic depressive illness
EMIL KRAEPELIN
IDENTIFY
Schizophrenia Identified four
fundamental symptoms and accessory symptoms
4 A’s
EUGENE BLEULER
Just brush up Schizophrenia – the gain of function as well as the loss of
function ( Tamminga C.A, Kaplan & Sadock,2009)
Distortion in perception, emotion, thinking, cognition and behavior (Ruiz, Sadock & Sadock, 2015)
Disturbs the most basic function that give a normal person a feeling of individuality, uniqueness and self direction (ICD-10,2007)
Onset is usually before 25 years, persists throughout the life and affects persons of all economic classes. (Ruiz, Sadock & Sadock, 2015)
RISK FACTORS1) Gender and age2) Reproductive factors3) Infection and birth season4) Substance abuse5) Socio economic and cultural
factors
BIOLOGICAL ETIOLOGY
1. GENETIC THEORIES OF SCHIZOPHRENIAFAMILY STUDIESTWIN STUDIES ADOPTION STUDIES
2. BIO CHEMICAL THEORY OF SCHIZOPHRENIADOPAMINE HYPOTHESISSTRESS DIATHESIS MODELVIRAL HYPOTHESIS
3. NEURODEVELOPMENTAL THEORIESBRAIN STRUCTURE AND ENLARGED VENTRICLESABBERANT CONNECTIVITYALTERED SYNAPTIC CIRCUITY
FAMILY STUDIES Schizophrenia DO run in the
family 1st systematic study by Ernst
Rudin An individual's FDR (parents,
siblings and off springs) share, on an average, 50% of his genes while his second degree relatives (grandparents, aunts, uncles and grand children) share, on an average,25% of the genes.
FAMILY STUDIES(Continues….) Hirsch and Leff made an extensive review of studies which
supports the following hypotheses:
1.More parents of schizophrenics are psychiatrically disturbed than parents of normal children and more of the mothers are schizoid.
2.There appears to be a link between allusive thinking in schizophrenics and their parents.
3.The parents of schizophrenics show more conflict and disharmony than the parents of other psychiatric patients.
4.The parents of schizophrenics show more abnormalities in their communications.
EVIDENCES Pope HG Jr, Jonas J, Cohen B, Lipinski JF(1982) , studied 199
FDR and they could not find any significant relationship between genetic component and prevalence of schizophrenia.
Kender (1985) studied the morbidity risk for psychiatry illnesses among 62 schizophrenic patients and he found that the morbid risk of schizophrenia is significantly greater(18 times more) in relatives of schizophrenia
Wolyniec(1992) studied the morbidity risk in the families of male and female schizophrenics and reported that the relatives of female schizophrenics are more prone to develop schizophrenia than males.
TWIN STUDIES
TWIN STUDIES Hypothesis- the genes really did make a difference
and that familial aggregation of schizophrenia was not simply due to shared family environment
Gottesman and Shields(1972) MZ (N=22) 58% morbid risk DZ(N= 33) 12% morbid risk
TWIN STUDIES The major question that arises is whether
schizophrenia in a MZ twin, with an unaffected co-twin, represents a sporadic or a non-genetic `phenocopy' of the illness.
The results of the study by Gottesman II, Shields J (1976) in Danish sample would argue against this.
Individual differences in the evoking environments and the timing of the genetic activation during the intrauterine and early postnatal periods may have differential effects on the genome.
ADOPTION STUDIES
•Kety SS, Rosenthal D, Wender PH, Schulsinger F, Jacobsen B(1972)
•Studied Danish Population
•3 groups
•Found that biological offsprings had higher rate of schizophrenia than adopted
Gottesman (1991)
1) Both parents = 46% risk
2) One schizophrenic parent = 16% risk
3) If a sibling has schizophrenia = 8% risk
4) If a grandparent has schizophrenia = 5% risk
5) If the identical twin of one parent hasschizophrenia = 17% risk.
BIO CHEMICAL THEORY OF
SCHIZOPHRENIA
DOPAMINE HYPOTHESIS Abnormally high dopamine activity
Neuroleptics control positive symptoms by reducing dopamine activity
L-Dopa, a dopamine pre-cursor (usually given to Parkinson’s patients), brings on schizophrenic symptoms in clinically normal people
the increase of dopamine in meso-cortical dopamine pathway could improve negative ,cognitive and affective symptoms of Schizophrenia.(Gordana Rubeša, Lea Gudelj & Natalija Kubinska, 2011)
STRESS DIATHESIS MODEL
combines the insights gained from biological and environmental approaches.
schizophrenics inherit a vulnerability to the disorder which makes them overly sensitive to their social environment
stressful life events, family dysfunction, trauma
VIRAL HYPOTHESIS
Schizophrenia gene? infants are infected
during the prenatal period, more particularly during late pregnancy or shortly after birth and only manifest symptoms many years later.
NEURODEVELOPMEAL THEORIES
ALTERED SYNAPTIC CIRCUITY
Continues…
Cortical neurons from subjects with schizophrenia exhibit:
(1) smaller somal volume, (2) decreased spine density, (3) decreased dendritic length, and (4) decreased terminals (as demonstrated by
decreased presynaptic markers) postmortem findings contribute to the
hypothesis that schizophrenia stems from altered synaptic circuitry.
BRAIN STRUCTURE
reduced brain weight; enlarged ventricles; abnormalities in the cortex and hippocampus.
left amygdale is generally smaller than the right in normal people but the same size in schizophrenics. (Tom Burns, Harrison P, Cown P, 2012)
ABERRANT CONNECTVITY Abnormal connectivity in
neural circuits and brain regions(Tom Burns, Harrison P, Cown P, 2012)
Arises developmentally Studied by MRI scan Given cognitive tasks to
assess
LEARNING THEORIES
LABELLING THEORYSOCIAL LEARNING THEORY
LABELLING /FAULTY LEARNING
SOCIAL LEARNING THEORY
SOCIAL LEARNING THEORY Family environment Learning through observation and modeling Ullman and Krasner (1969) observed mental health nurses in
their interactions with patients and concluded that staff actually reinforce schizophrenic behaviour by giving more attention to these patients.
Expressed emotion (EE)- way in which family speaks reflects criticism, hostile feelings, emotional over involvement or over concern. (trying to recover)
Suffer relapse if living in families with high Expressed emotions.
COGNITIVE THEORY
FRITH MODEL HEMSLEYS THEORY ZIMBARDO’S A RATIONAL PATH TO
MADNESS
FRITH MODEL Faulty attention system unable to distinguish between actions that are brought
about externally or generated internally. For Frith this accounts for the positive symptoms of
schizophrenia, such as hallucinations, delusions and disorganised speech.
Divided into 3 cognitive processes1. in ability to do willed actions2. Inability to regulate action3. Inability to monitor belief
HEMSLEYS THEORY Linked to memory and perception Focus on unimportant and
irrelevant factors Schemes overloaded Internal thoughts not recognized •Internal thoughts are often not
recognized as arising from memory and so are thought to be from an external source and experienced as auditory hallucinations
ZIMBARDOS A RATIONAL PATH TO MADNESS
Due to denial of sensation by others, a few people conclude that they hide truth
Eventually avoid all feedback
Strengthen the believe of persecution
REFERANCES Ahuja, N., (2011). A short textbook of psychiatry (7th edn.). New Delhi: Jaypee
Brothers Sadock, B.J., Sadock, V.A., & Kaplan, H.I., (2015).Kaplan and Sadock's Synopsis
of Psychiatry Behavioural Sciences/Clinical Psychiatry (11th edn.). Philadelphia: Wolters Kluwer
World Health Organization. (1992). The ICD-10 classification of mental and behavioural disorders: Clinical descriptions and diagnostic guidelines. Geneva: World Health Organization
Hirsch SR, Leff JP. Abnormalities in parents of schizophrenics. London, Oxford UniversityPress, 1975.
Pope HG Jr, Jonas J, Cohen B, Lipinski JF. Failure to find evidence of schizophrenia in firstdegree relatives of schizophrenic probands. American Journal of Psychiatry, 1982; 139:826-828.
Kendler KS, Catherine CM, Kenneth LD. Psychiatric illness in first degree relatives ofpatients with paranoid psychosis, schizophrenia and medical illness. British Journal ofPsychiatry, 1985; 147: 524-531
Wolyniec PS, Pulver AE, McGrath JA, Tam D. Schizophrenic gender and familial risk.Journal of Psychiatric Research, 1992; 26 (1): 17-27.
Wender PH, Rosenthal D, Kety SS, Schulsinger F, Weiner J. Cross fostering: A researchstrategy for clarifying the role of genetic and experimental factors in the etiology ofschizophrenia. Archives of General Psychiatry, 1974; 30: 121-128.
REFERENCES
Gottesman II, Shields J. Schizophrenia and genetics: A twin study. Vantage Point. New York, Academic Press, 1972; 17-33.
Gottesman II, Shields J. A critical review of recent adoption, twin and family studies of schizophrenia: Behavioural genetics perspectives. Schizophrenia Bulletin, 1976; 2: 360-398.
Gordana Rubeša, Lea Gudelj & Natalija Kubinska: ETIOLOGY OF SCHIZOPHRENIA AND THERAPEUTIC OPTIONS Psychiatria Danubina, 2011; Vol. 23, No. 3, pp 308–315
(Tom Burns, Harrison P, Cown P .(2011), shorter textbook of psychiatry .(6th edi.). , london: oxford university press.