Schizophrenia
1) Introduction to schizophrenia
Classification of mental disorder- process of organising symptoms into categories based on
which symptoms frequently cluster together
Schizophrenia- severe mental disorder where contact with reality is impaired (psychosis)
Positive symptoms of schizophrenia- atypical symptoms experienced as well as normal
experiences. (Hallucinations and delusions)
Hallucinations- positive symptom of schizophrenia. Sensory experiences- distorted perception
and things that don't exist
Delusions- positive symptom in schizophrenia involving beliefs that don't exist (person believes
they are someone else/ victim of conspiracy)
Negative symptoms of schizophrenia- atypical experiences representing loss of usual
experience (loss of clear thinking or 'normal' levels of motivation)
Speech poverty- negative symptom involving reduced frequency and quality of speech
Avolition- negative symptom involving loss of motivation to do tasks and lowered activity levels
Co-morbidity- occurrence of two disorders or conditions together (person has schizophrenia and
personality disorder). Two conditions diagnosed together.
Symptom overlap- occurs when two or more conditions share symptoms
Diagnosis and classification of schizophrenia
Most common in men, city dwellers and lower socio-economic groups. To diagnose a disorder,
disorders need to be distinguished by identifying the symptoms then classifying it as one
disorder. diagnosis - identifying symptoms using classification system to identify disorder.
Classification either DSM-5 (one positive symptom), ICD-10 (two negative symptoms)
Positive symptoms
Hallucinations- unusual sensory experiences may be distortion of reality. Can be picked up
from environment- (hearing voices) or see non-existing things
Delusions- beliefs not based in reality, bizarre behaviour, can lead to aggression
Negative symptoms
Speech poverty- reduced amount and quality of speech -also delayed response time. More
emphasis on speech disorganisation- muttering, changing topics mid sentence. DSM-5- positive
symptom of schizophrenia, speech poverty is negative symptom
Avolition- loss of motivation, low activity. Poor hygiene and grooming, lack of energy and
persistence in work or education
Evaluation:
-diagnosis of schizophrenia is its reliability (inter-rater reliability- when different diagnosing
clinicians reach same diagnosis for same individual. Test-retest reliability- when same clinician
reaches same diagnosis for same individual on two occasions. Osorio et al studied 180
individuals using DSM-5. Inter-rater reliability (+.97), test-retest reliability (+0.92). Means
schizophrenia diagnosis is consistently applied.
-diagnosis of schizophrenia is its validity (100 clients assessed, 68 diagnosed with
schizophrenia using ICD-10 and 39 with DSM-4, low criterion validity (Cheniaux et al)) Suggests
schizophrenia is either over or underdiagnosed according to diagnostic system showing that
criterion validity is low
, -schizophrenia diagnosis- co-morbidity with other conditions (around half of patients with
schizophrenia also have another diagnosis (depression) (Buckley et al.)) means schizophrenia
may not exist as a distinct condition
-schizophrenia diagnosis- gender bias (since 1980s more men than women have received
diagnosis of schizophrenia suggesting there’s bias in diagnosis, with women being
underdiagnosed due to having closer relationships and support) Underdiagnosis is gender bias
and means women may not receive beneficial treatment
-schizophrenia diagnosis- culture bias (UK Afro-Caribbean 10x more likely to be diagnosed than
white UK, due to norms in Afro-Carribean communities misinterpreted by UK clinicians) Means
Afro-Caribbean people may be discriminated against by culturally-biased diagnostic system.
-schizophrenia diagnosis- symptom overlap with other conditions (Symptoms of schizophrenia
(bipolar disorder overlaps with schizophrenia, both conditions involve delusions and avolition,
making diagnosis and distinguishing between them difficult) Means schizophrenia doesn’t exist
as a distinct condition and hard to diagnose
2)Biological explanations for schizophrenia
Genetics- genes consisting of DNA strands
Neural correlates- patterns of structure or activity in brain that occur in conjunction with
experience and origins of experience
Dopamine- neurotransmitter with an excitatory effect linked to sensation of pleasure
Genetic basis of schizophrenia
Family studies- risk of schizophrenia increases with genetic similarity to someone with the
condition, (2% for aunt, 9% for sibling, 48% identical twin) (Gottesman)
Candidate genes- schizophrenia is polygenic (genes code for neurotransmitters like dopamine)
and aetiologically heterogeneous (can result from different combinations of risk factors). Large
study- 37,000 people with schizophrenia compared to 113,000 controls, 108 genetic variations
associated with increased risk of schizophrenia (Ripke et al)
Role of mutation- Genetic vulnerability in people with no family history. Explained by mutation
in parental DNA caused by radiation or viral infection. E.g. 0.7% with fathers under 25 to 2% risk
in fathers over 50 (Brown et al.)
Evaluation:
-genetic explanation- strong evidence base- (Family studies (e.g. Gottesman), adoption studies
show that biological children of parents with schizophrenia have increased risk even if grown up
with adoptive family. (Tiernari et al.), twin studies, concordance rates- MZ 33% and DZ 7%
concordance (Hilker et al.)) shows some people more vulnerable to schizophrenia as result of
genetic make-up.
-evidence showing environmental factors increase risk of developing schizophrenia- (Biological
factors e.g. birth complications (Morgan et al.) and cannabis use (Di Forti et al.) and
Psychological factors e.g. childhood trauma (67% people with schizophrenia and psychotic
condition had at least one childhood trauma vs 38% of matched group with non-psychotic
mental health problems(Morkved et al)) means genetic factors can’t show complete explanation
for schizophrenia.
1) Introduction to schizophrenia
Classification of mental disorder- process of organising symptoms into categories based on
which symptoms frequently cluster together
Schizophrenia- severe mental disorder where contact with reality is impaired (psychosis)
Positive symptoms of schizophrenia- atypical symptoms experienced as well as normal
experiences. (Hallucinations and delusions)
Hallucinations- positive symptom of schizophrenia. Sensory experiences- distorted perception
and things that don't exist
Delusions- positive symptom in schizophrenia involving beliefs that don't exist (person believes
they are someone else/ victim of conspiracy)
Negative symptoms of schizophrenia- atypical experiences representing loss of usual
experience (loss of clear thinking or 'normal' levels of motivation)
Speech poverty- negative symptom involving reduced frequency and quality of speech
Avolition- negative symptom involving loss of motivation to do tasks and lowered activity levels
Co-morbidity- occurrence of two disorders or conditions together (person has schizophrenia and
personality disorder). Two conditions diagnosed together.
Symptom overlap- occurs when two or more conditions share symptoms
Diagnosis and classification of schizophrenia
Most common in men, city dwellers and lower socio-economic groups. To diagnose a disorder,
disorders need to be distinguished by identifying the symptoms then classifying it as one
disorder. diagnosis - identifying symptoms using classification system to identify disorder.
Classification either DSM-5 (one positive symptom), ICD-10 (two negative symptoms)
Positive symptoms
Hallucinations- unusual sensory experiences may be distortion of reality. Can be picked up
from environment- (hearing voices) or see non-existing things
Delusions- beliefs not based in reality, bizarre behaviour, can lead to aggression
Negative symptoms
Speech poverty- reduced amount and quality of speech -also delayed response time. More
emphasis on speech disorganisation- muttering, changing topics mid sentence. DSM-5- positive
symptom of schizophrenia, speech poverty is negative symptom
Avolition- loss of motivation, low activity. Poor hygiene and grooming, lack of energy and
persistence in work or education
Evaluation:
-diagnosis of schizophrenia is its reliability (inter-rater reliability- when different diagnosing
clinicians reach same diagnosis for same individual. Test-retest reliability- when same clinician
reaches same diagnosis for same individual on two occasions. Osorio et al studied 180
individuals using DSM-5. Inter-rater reliability (+.97), test-retest reliability (+0.92). Means
schizophrenia diagnosis is consistently applied.
-diagnosis of schizophrenia is its validity (100 clients assessed, 68 diagnosed with
schizophrenia using ICD-10 and 39 with DSM-4, low criterion validity (Cheniaux et al)) Suggests
schizophrenia is either over or underdiagnosed according to diagnostic system showing that
criterion validity is low
, -schizophrenia diagnosis- co-morbidity with other conditions (around half of patients with
schizophrenia also have another diagnosis (depression) (Buckley et al.)) means schizophrenia
may not exist as a distinct condition
-schizophrenia diagnosis- gender bias (since 1980s more men than women have received
diagnosis of schizophrenia suggesting there’s bias in diagnosis, with women being
underdiagnosed due to having closer relationships and support) Underdiagnosis is gender bias
and means women may not receive beneficial treatment
-schizophrenia diagnosis- culture bias (UK Afro-Caribbean 10x more likely to be diagnosed than
white UK, due to norms in Afro-Carribean communities misinterpreted by UK clinicians) Means
Afro-Caribbean people may be discriminated against by culturally-biased diagnostic system.
-schizophrenia diagnosis- symptom overlap with other conditions (Symptoms of schizophrenia
(bipolar disorder overlaps with schizophrenia, both conditions involve delusions and avolition,
making diagnosis and distinguishing between them difficult) Means schizophrenia doesn’t exist
as a distinct condition and hard to diagnose
2)Biological explanations for schizophrenia
Genetics- genes consisting of DNA strands
Neural correlates- patterns of structure or activity in brain that occur in conjunction with
experience and origins of experience
Dopamine- neurotransmitter with an excitatory effect linked to sensation of pleasure
Genetic basis of schizophrenia
Family studies- risk of schizophrenia increases with genetic similarity to someone with the
condition, (2% for aunt, 9% for sibling, 48% identical twin) (Gottesman)
Candidate genes- schizophrenia is polygenic (genes code for neurotransmitters like dopamine)
and aetiologically heterogeneous (can result from different combinations of risk factors). Large
study- 37,000 people with schizophrenia compared to 113,000 controls, 108 genetic variations
associated with increased risk of schizophrenia (Ripke et al)
Role of mutation- Genetic vulnerability in people with no family history. Explained by mutation
in parental DNA caused by radiation or viral infection. E.g. 0.7% with fathers under 25 to 2% risk
in fathers over 50 (Brown et al.)
Evaluation:
-genetic explanation- strong evidence base- (Family studies (e.g. Gottesman), adoption studies
show that biological children of parents with schizophrenia have increased risk even if grown up
with adoptive family. (Tiernari et al.), twin studies, concordance rates- MZ 33% and DZ 7%
concordance (Hilker et al.)) shows some people more vulnerable to schizophrenia as result of
genetic make-up.
-evidence showing environmental factors increase risk of developing schizophrenia- (Biological
factors e.g. birth complications (Morgan et al.) and cannabis use (Di Forti et al.) and
Psychological factors e.g. childhood trauma (67% people with schizophrenia and psychotic
condition had at least one childhood trauma vs 38% of matched group with non-psychotic
mental health problems(Morkved et al)) means genetic factors can’t show complete explanation
for schizophrenia.
