Week 4 RF-Insights into aetiology and experiences of schizophrenia Flashcards
What is schizophrenia?
-A serious condition that affects how a person thinks/feels/behaves.
-Struggle to differentiate reality from thoughts.
-A constellation of psychotic/negative/cognitive symptoms.
-Often diagnosed differently in ICD-11 vs DSM-V (Valle, 2020).
-Psychotic can be written as positive symptoms in some literature
What are Psychotic / Negative symptoms / Cognitive symptoms of schizophrenia?
Psychotic symptoms:
-Hallucinations
-Delusions
-Thought Disorder=thought broadcasting (people can hear your thoughts)
Negative symptoms:
-Social withdrawal
-Limited emotions
-Loss of motivation
Cognitive symptoms:
-Trouble processing/using information
-Attention deficits
What are the aetiological factors of Schizophrenia?
-Genetics
-Neurotransmitters
-Brain structure
-Drug use
-Stress
How can neurotransmitters cause schizophrenia?
-The dopamine hypothesis – SZ arises from an excess of dopamine/overstimulation of dopamine receptors in the mesolimbic area of the brain.
-Symptoms also arise from a lack of dopamine and the under-stimulation of dopamine receptors in the prefrontal cortex (da Silva Alves et al., 2008).
-Positive symptoms come from increased subcortical release of dopamine, which increases D2 receptor activation (Shen et al., 2012).
-Negative symptoms come from reduced D1 receptor activation in the prefrontal cortex/nucleus caudatus (O’Donnell & Grace, 1998).
What are the Pros of the aetiology of schizophrenia - Neurotransmitters
Great deal of evidence:
-PET studies have found the differences in dopamine in the prefrontal cortex, cingulate cortex, and hippocampus between schizophrenia patients and controls (Patel et al., 2010).
Practical implications:
-The antipsychotic drugs chlorpromazine and haloperidol block dopamine receptors, reducing psychotic symptoms (Baumeister, 2013).
Animal models:
-Rearing rats in social isolation reduces dopamine in the prefrontal cortex (Möller et al., 2012)
-Use chromatography on brain juices of rats by decapitating them
What are the Cons of the aetiology of schizophrenia - Neurotransmitters
Animal studies:
-How similar are rat social behaviour to human behaviours, can this be extrapolated?
-How similar are rat brains?
-The rats had decreased dopamine, but did they experience psychotic symptoms specifically?
-We can’t ask rats what they’re feeling
Underpowered studies:
-Underpowered studies can produce false-negative (type II error) results, inflated effect sizes, and false-positive associations.
-Studies that report significant findings are more likely to be published: the file drawer effect.
How does brain structure cause schizophrenia?
-MRI studies have found that those with SZ have reduced gray matter volumes of the medial temporal, superior temporal, and prefrontal areas.
-Areas are associated with episodic memory, processing audio, and decision-making (Karlsgodt et al., 2010)
-Postmortem studies show reduced cortical grey matter reduction is associated with reduced dendritic complexity and synaptic density (Glantz & Lewis, 2000).
-This is thought to change communication between neurons and surrounding brain structures.
-Brain imaging techniques for SZ include fMRI, MRI, PET.
-It’s their own internal monologue but is externally mis-distributed (hence why processing audio is affected)
-People with SZ have fewer dendrites (3rd point)
What are the Pros of the aetiology of schizophrenia - Brain Structures
Imaging pre-onset:
-Imaging can predict subsequent psychotic experiences, and enable early intervention.
-Can help to predict which treatments may be the most effective for those struggling with SZ symptoms.
Biological foundation:
-A predominant biological cause tends to remove stigma associated with mental distress.
-Also tends to remove the blame from the p
What are the Cons of the aetiology of schizophrenia - Brain Structures
Brain imaging has methodological limitations:
-Dead salmon (Bennett et al., 2009).
-Asked the salmon what emotion these people were experiencing
-N<20 for groups within imaging studies – underpowered.
Circular logic:
-Do brain structure abnormalities cause SZ or does SZ cause brain structure abnormalities?
-Lack of longitudinal research.
What did Hengartner & Moncrieff (2018) say about the dopamine hypothesis?
“In its current third version, the dopamine hypothesis asserts that environmental stress and substance abuse, in interaction with a genetic susceptibility, lead to dopamine dysregulation, and that increases in striatal presynaptic dopamine concentration causes psychosis”.
What is the Background of Lyon et al’s (2021) Covid-19 study?
-The COVID-19 pandemic poses significant additional psychological stressors to those with mental health difficulties.
-Social distancing policies reduce social support and formal assistance (Kozloff et al., 2020).
-Information overload – the “infodemic” (Hamada & Fan, 2020).
-Lack of focus on experiences of psychosis during pandemics.
-Previous epidemic/pandemic research is inconsistent (Brown et al., 2020; González-Blanco et al., 2020; Pinkham et al., 2020).
-Last pandemics have been swine flu, spanish flu, ebola etc.,
-Our study aimed to address this issue, by investigating how people with psychosis experience of the pandemic
What is the Methods Design of Lyon et al’s (2021) Covid-19 study?
-Data gathered from public discussion forum Reddit. r/psychosis
-Systematically searched subreddits for relevant posts and comments.
-Terms: “COVID”, “virus”, “pandemic”, “corona”, “quarantine”.
-Excluded experiences of others, not COVID related, advice only.
-Wanted first hand experiences not others e.g., their sister’s experience
-N=65.
-Inductive thematic analysis with a constructivist/descriptive approach.
What is the Methods Ethical Issues of Lyon et al’s (2021) Covid-19 study?
-User distress from posts being used in research without consent.
-Seeking consent is not practical (Smedley & Coulson, 2021). (especially since anonymised). Users know others can see it so consent isn’t necessarily as prioritised as usual studies
-Large number of members means posts are more public than private. (don’t need an account to see posts)
-Posts contain sensitive information.
-Not analysing personal characteristics.
-Practical value outweighs potential harms.
-Usernames were assigned a number.
-Quotes were slightly altered so reverse search fails.
What is the Methods Analysis of Lyon et al’s (2021) Covid-19 study?
-Independent coding (like social blog last year/thematic analysis)
-Codes organised into themes
-Themes discussed and agreed
What were the Results of Lyon et al’s (2021) Covid-19 study?
-Declining mental health
-Changed psychosis experiences
-Personal positive and negative coping experiences
-Social connectedness and disconnectedness
-COVID-19 as a metaphor
