Schizophrenia AO1 Flashcards
(10 cards)
What are the positive and negative symptoms of schizophrenia according to classification systems?
Positive symptoms (added experiences): hallucinations (distorted sensory input with no basis in reality) and delusions (false beliefs, e.g., paranoia or identity confusion).
Negative symptoms (loss of normal function): speech poverty (reduced fluency and quality of speech) and avolition (lack of motivation, lowered activity levels).
Classification involves matching symptoms to diagnostic criteria in systems like DSM-5 and ICD-10.
How do comorbidity and symptom overlap affect the classification of schizophrenia?
Comorbidity: When two or more disorders (e.g., schizophrenia and depression) occur together, it questions whether they are truly separate conditions (Buckley et al. found 50% of SZ patients also had depression or substance abuse).
Symptom overlap: Many symptoms (e.g., delusions, avolition) are shared with bipolar disorder, making it hard to distinguish SZ as a separate condition. Both undermine diagnostic validity.
What is the genetic explanation for schizophrenia?
Schizophrenia has a genetic basis, supported by family, twin, and adoption studies. It is polygenic (involving many genes) and aetiologically heterogeneous (different combinations of genes may lead to SZ). For example, Gottesman (1991) found MZ twins have a 48% risk if their twin has SZ, compared to 17% in DZ twins. Ripke et al. (2014) identified 108 genetic variations linked to SZ, many coding for neurotransmitters like dopamine and glutamate.
What is the original dopamine hypothesis of schizophrenia?
The original dopamine hypothesis (Karlsson) proposed hyperdopaminergia—excess dopamine in the subcortex, especially in pathways to Broca’s area—explains positive symptoms like auditory hallucinations and disorganised speech. Antipsychotic drugs that block dopamine receptors reduce these symptoms, supporting the theory.
How has the dopamine hypothesis been updated?
Davis et al. (1991) suggested hypodopaminergia—abnormally low dopamine in the prefrontal cortex—explains negative symptoms like avolition and cognitive impairment. The modern view sees SZ as involving both hyper- and hypo-dopaminergic activity, depending on brain region.
What are neural correlates and how do they explain schizophrenia?
Neural correlates are brain structures/functions linked to SZ symptoms. Juckel et al. (2006) found reduced activity in the ventral striatum correlated with avolition (a negative symptom). Allen et al. (2007) found reduced activity in the superior temporal gyrus and anterior cingulate in patients experiencing auditory hallucinations (positive symptoms).
How can mutation and epigenetics explain schizophrenia?
SZ can occur without family history. Mutations in paternal DNA (e.g., due to radiation or age) may increase risk. Brown et al. (2002) found offspring of fathers over 50 are more than twice as likely to develop SZ than those under 25. This shows biological changes beyond inheritance can influence risk.
Compare biological explanations to family dysfunction explanations of SZ.
Biological theories focus on heritability (genes, dopamine, brain abnormalities), while psychological explanations like the double-bind theory (Bateson) argue that mixed family messages lead to disordered thinking. Read et al. found 69% of women with SZ reported childhood abuse. Both may interact—genes predispose, trauma triggers.
What are the 3 main family dysfunction theories explaining schizophrenia?
Schizophrenogenic Mother (Fromm-Reichmann): Cold, controlling, and rejecting parenting creates secrecy and tension, leading to paranoid delusions.
Double-Bind Theory (Bateson): Conflicting messages + punishment → confusion, disorganised thinking, paranoid delusions.
Expressed Emotion (EE): High levels of criticism, hostility, and emotional over-involvement increase relapse risk and may trigger SZ in vulnerable individuals.
What is meant by dysfunctional thought processing in SZ?
SZ symptoms stem from abnormal cognition.
* Metarepresentation (Frith et al.): Disruption → misattributed thoughts = hallucinations and delusions.
* Central Control: Inability to suppress automatic responses → derailment of thought, disorganised speech.
* Dysfunction shown via underactivity in the ventral striatum (avolition) and temporal gyri (hallucinations).
