Schizophrenia Flashcards
What are the three symptoms associated with a split in the psyche?
- disorganised thought processes
- split between intellect and emotion
- split between intellect and external reality
What are the five main symptoms of schizophrenia?
- auditory hallucinations
- delusions (of grandeur, of persecution)
- disordered thinking
- lack of control (alien power)
- emotional and volitional changes (‘flat’ emotions, little initiative, no energy)
What did Wing argue?
For a distinction between primary (intrinsic to the disorder) and secondary (result from primary) symptoms.
Name some primary symptoms.
Hallucinations, delusions, thought disorders, apathy, emotional blunting.
Name some secondary symptoms and the two categories.
Social - unemployment, social drift, institutionalisation, rejection & prejudice.
Psychological - dependant, poor coping, depression, loss of confidence, no motivation.
What are positive and negative symptoms?
Positive - additional to ‘normal’ behaviour or expression.
Negative - deficit in ‘normal’ behaviour patterns.
What are type 1 and type 2 symptoms?
Type 1 (positive) - responsive to drug treatments, limbic system abnormalities. Type 2 (negative) - less responsive to drugs, abnormalities in frontal lobes and enlarged ventricles.
What is the third cluster of symptoms?
There is no universal agreement about a simple positive/negative split between symptoms. It is argued that a third cluster - disorganised schizophrenia - exists, which is largely associated with chaotic speech and behaviour.
How are the symptoms of schizophrenia described?
As being on a continuum, rather than a dichotomy.
What is the issue with labelling people as having ‘schizophrenia’?
The term can be misleading, despite it being convenient. It is likely there are many different types of severe mental disorders that we currently call schizophrenia, when they have one thing in common; a loss of contact with reality.
What is the DSM-IVR?
Diagnostic and Statistical Manual, 4th Edition Revised. Widely used for the diagnosis of abnormalities.
What are; A characteristic, B and C symptoms?
A characteristic - two or more of the following each present for a one month period; delusions, hallucinations, disorganised speech, disorganised or catatonic behaviour, and negative symptoms (affective flattening, alogia).
B social/occupational dysfunction - one or more major areas of functioning such as work, interpersonal relations or self-care are markedly below the level achieved prior to the onset.
C duration - signs of the disturbance persist for at least six months. This period must include at least one month of symptoms (or less if treatment successful) that meet criterion A.
What is alogia?
Speech that is dramatically reduced in content.
What are the types of schizophrenia, and describe them>
Paranoid - one or more delusions, frequent auditory hallucinations. None of the following prominent; disorganised speech, disorganised/catatonic behaviour, flat/inappropriate behaviour.
Catatonic - two of the following are present; immobility (including waxy flexibility) or stupor, excessive motor activity, extreme negativism or mutism, posturing, stereotyped movements, prominent mannerisms/grimacing, echolalia or echopraxia.
Disorganised - all of the following are prominent; disorganised speech, disorganised behaviour, flat effect.
Undifferentiated - criterion A symptoms are present, but the criteria are not met for the paranoid, disorganised, or catatonic type.
Residual - absence of prominent delusions, hallucinations, disorganised speech, catatonic behaviour. There are negative symptoms, or two or more symptoms listed in criterion A in an attenuated form.
What is echolalia?
Repetition of a word or phrase.
What is echopraxia?
The repeating of gestures made by others.
What are the three biological explanations of schizophrenia?
Genetics, neurochemical, and neuroanatomical.
Overview of genetic explanation.
Schizophrenia tends to run in families, and studies show the closer the familial relationship, the higher the concordance. The general risk of schizophrenia in the population is 1%.
What are the percentage risks for schizophrenia in relation to family? Who was this meta-analysis by?
Gottesman and Shields.
Your ______ has schizophrenia;
One parent - 5.6% Sibling - 10.1% Sibling and one parent - 12.9% Both parents - 46.3% Grandparent - 3.7%
What type of studies do they use to unravel genetics and environment?
Adoption studies.
Describe twin studies. Give evidence.
MZ twins have 100% genes in common, DZ have 50%. If schizophrenia was a purely genetic disorder, this would predict that when one twin has been diagnosed with schizophrenia the rate of concordance would be higher in MZ than DZ twins. This has shown to be the case in a met-analysis (Gottesman and Shields).
MZ concordance - 46%
DZ concordance - 14%
Describe adoption studies. Give evidence.
These studies are typically of children adopted within two weeks of birth from their mother, who has schizophrenia. These children have no common genes with their adoptive family, where no one has schizophrenia. This, genes an environment are seperated.
Heston did a study of 47 mothers with schizophrenia, whose children were adopted within days to psychiatrically well mothers. He found the incidence of schizophrenia in the children to be 16%. This is well above the national average, suggesting a genetic influence.
Evaluate the genetic explanation (5 points).
- The 46% concordance for MZ twins suggests a major contribution of genotype.
- Concordance for MZ twins is about three times that of DZ twins, but there is still a discordance rate of 40% which could show there is more of an environmental cause. However, half of the discordant group go on to develop a schizoid or similar disorder, thus if a broader definition of ‘schizophrenia’ is used, MZ concordance rate is higher.
- Twin studies haven always contained small samples due to the rare incidence of both twins and schizophrenia in the population.
- Evidence from normal twin pairs suggests that MZ twins are reared in a more similar environment than DZ twins, meaning nurture may explain the higher concordance for MZ twins.
- Findings from adoption studies suggests inheritance plays a part in schizophrenia and there may be a genetic predisposition to the disorder.
Describe the neurochemical explanation of schizophrenia.
Investigation of neurotransmitters can be carried out in three ways; looking for evidence of metabolites in urine and blood, post-mortem in brain tissue, and neuroimaging techniques (PET scan).
The activity of neurotransmitters such as dopamine and the enzyme responsible for its metabolism (monoamine oxidase, MAO) has been investigated.
Describe the early (outdated) dopamine hypothesis. Give evidence.
It was first thought that excessive dopaminergic activity in the brain was the cause of schizophrenic symptoms. Evidence for this came from;
- Drugs that increase dopaminergic activity (amphetamines) result in psychotic symptoms.
- They also exacerbate psychotic symptoms in people with schizophrenia.
- Neuroleptic drugs that block the dopaminergic neurons reduce psychotic symptoms.
Describe the new and more accurate dopamine hypothesis. Give evidence.
The old hypothesis was difficult to support because post-mortem studies didn’t show consistent evidence for an increased dopamine level. This led to the theory that it was really the heightened sensitivity of the receptors for dopamine in the brain that led to an abundance of the chemical and thus to schizophrenic symptoms. Evidence came from;
- Post-mortem studies have shown that there are more D2 (dopamine) receptors in the brains of people with schizophrenia than there are in normal brains.
- Studies using PET scans have reported a substantial increate in D2 receptors in patients with schizophrenia.
- Seeman used PET and found six times the density of D4 receptors in the brains of people with schizophrenia (D4 is a subtype of receptor, similar to D2).
Evaluate the neurochemical explanation (3 points).
- It isn’t clear whether the increase in D2 receptors found in post-mortems is the cause of the pathology or an effect of the neuroleptic drugs taken as it is known that such drugs are attracted to this particular receptor.
- Neuroimaging studies by Pearlson were carried out on patients who had not been exposed to neuroleptic drugs, and thus ruled out the issue with post-mortem studies.
- It is now clear that the neurotransmitter systems interact and that the mapping of these cortical pathways is only just being explored - other neurotransmitters could be involved, and it could actually be neurotransmitters interacting.
Briefly describe the history of the neuroanatomical explanation.
The brains of schizophrenics are compared to that of controls on various things such as size of anatomical structure, hemisphere differences and cell counts. Initially, any comparison could only be carried out in post-mortem which can be problematic; for example the neuroleptic drugs used to treat schizophrenia may have caused any abnormality found. New techniques (MRI) allow living brain images o be investigated and consistent chance in particular areas have been identified.
Describe the structure of the schizophrenic brain.
Limbic system - this is a subcortical structure that includes the hippocampus and amygdala. Significant cell loss has been found in these structures at post mortem in schizophrenic patients. These findings have been confirmed with more recent MRI scans. There is also evidence of unusual cell connections in the hippocampus.
Corpus callosum - this is a large bundle of fibres and connects the two hemispheres of the brain. Studies show that the gender differences in the thickening of these fibres in normal individuals are reversed in people with schizophrenia.
Abnormal early brain development in the third trimester of pregnancy when the last stage of the development of the cerebral cortex occurs, is thought to be associated with schizophrenia. The two hemispheres of the brain are asymmetrical, particularly in the tempero-parietal region of the cortex. Bothe post-mortem and imaging studies have shown that this asymmetry is much less evident in patients with schizophrenia.
Brain imaging studies - have found significant differences in both structure and function of the schizophrenic brain.
Studies have shown that people with schizophrenia have reduced brain tissue and enlarged ventricles. A meta-analysis by Raz and Raz of studies comparing ventricular volume reported a significant increase in size in over half the sample and an overall effect size of 0.6. This may be linked to major functional abnormalities.
What is the study on the neuroanatomical explanation?
Suddath took fifteen discordant MZ twin pairs, only one of which was diagnosed with schizophrenia, were given MRI scans to determine any differences in brain structure. The co-twin with schizophrenia had a smaller bilateral hippocampus in 14 of the 15 pair, and the co-twin with schizophrenia had larger ventricles.
Conclusion: when genotype is controlled (100% concordance) there is significantly diminished brain volume in the twin with schizophrenia.
Issue: it is difficult to establish whether the smaller hippocampus found is cause or effect.
What is hypofrontality?
Imaging techniques can detect cerebral blood flow (CBF) in parts of the cortex. At rest, people with schizophrenia show evidence of underactivity in the tempero-frontal areas of the cortex. This is particularly evident in chronic patients.
Evaluate the neuroanatomical explanation (3 points).
- Attempts to link structural chances to symptoms have not yet shown consistent findings. Lewis considered 18 studies and found no significant link between enlarged ventricles and negative symptoms associated with schizophrenia.
- A variety of brain mechanisms seem to be implicated in schizophrenia but non is sufficiently understood for researchers to say it provides a causal link.
- A number of environmental risk factors contribute to the onset of schizophrenia and it is more realistic to propose that biological factors contribute towards an individual’s liability to develop schizophrenia.
What does the cognitive approach attempt to explain?
Specific symptoms, in particular positive symptoms such as hallucinations and delusions.
How does the cognitive approach explain hallucinations?
Up to 73% of people diagnosed with schizophrenia report experiencing auditory hallucinations. Bentall assumes that hallucinations occur when people mistake their own internal, mental or private events for external, publicly observable events - the imaginary world is mistaken for the real world. The five-factor model expands on this.
Explain the five-factor model.
Slade and Bentall proposed this theory, which explains the onset of such schizophrenia-type symptoms.
- Stress-induced arousal. In times of stress we are in a heightened state of arousal and information is not processed effectively making it difficult to decide what is real.
[down to a cycle] - Predisposition. Some people hallucinate more easily. They have more suggestibility.
- Environment. Influences hallucinatory responses (very quiet or noisy conditions).
- Reinforcement. Hallucinations bring relief by reducing anxiety.
- Expectancy. People see or hear what they believe exists.
