developmental psychology - clinical Flashcards
when does schizophrenia develop?
- typical age of onset = early to mid 20s in males and late 20s for females
- several perinatal and birth complications e.g. premature births are also associated with the development of Sz
what does the dopamine hypothesis suggest about the development of Sz?
- positive symptoms caused by excess dopamine in the mesolimbic pathways and negative symptoms from a deficit of dopamine in mesocortical areas
- this links to dopamine activity peaking in adolescence and may further set the stage for onset of symptoms
- PFC also matures at this stage
how does brain structure and neurotransmitters relate to each other on the concept of super-sensitivity?
- there is a pathway rich in glutamate that runs from the PFC to the mesolimbic pathway
- these areas said to be smaller in volume so it is underdeveloped
- lower levels of glutamate activity lead to lower basal release of dopamine
- this causes dopamine receptors to be hypersensitive so they overreact giving positive symptoms
what did wright et al and susser et al find about Sz and development?
- wright = incidence of Sz in children born to mothers who had flu during pregnancy, especially when between 4 and 7 months
- susser = children conceived during famine had twice the normal risk of developing Sz
how does brain injury link to developmental?
- if the brain damage occurs early and then Sz develops later onwards it could be because the brain injury interacts with normal brain development
- PFC develops typically in adolescence so damage in the area before birth wouldn’t initially show
how does brain development overall link to Sz?
- as the brain develops, if any environmental or genetic factors were slow to develop then it would impact how the brain is able to deal with neurotransmission which results in Sz
what is a strength of the brain structure explanation ?
- brain scans provide scientific objective data e.g. fMRIs
what is a weakness of the brain structure explanation?
- the focus is only on biological factors so it is a reductionist explanation
what is a strength of the neurotransmitters explanation?
- falkai et al = studied autopsies and found that those with Sz had a larger than usual number of dopamine receptors
what is a weakness of the neurotransmitter explanation?
- newer antipsychotics have been found to actually increase dopamine levels in some parts of the brain which contradicts the dopamine hypothesis
what have family studies found about the rate of Sz?
- risk for the general population = 1%
- second degree Sz relative = 6%
- first degree Sz relative = 17%
what are two weaknesses about the findings of family studies?
- family study research has failed to isolate a single dominant or recessive gene that causes the illness
- tiwari = fewer than 1/3 of people with Sz have a family history of the disorder
what have adoption studies found and what is a supporting study of this?
- Sz spectrum disorders are more frequent in adopted children of Sz mothers than control
- kety et al = concordance rate of Sz in 33 adopted twin pairs and there was a high concordance rate even amongst adopted twins which showed a clear genetic factor
what is found about NGR1?
- NGR1 is expressed at central nervous system synapses and has a clear role in activation of NT receptors
- variations of the gene contribute to the pathogenesis of Sz
what is a supporting study of NGR1?
- stefansson found that the NGR1 mutation mice are hyperactive
- clozapine reduced the hyperactivity
- further supports that the NGR1 mutation is related to Sz phenotypes
