IMH Topic 2- The Medical Model Flashcards
Background- the biochemical explanation of mental illness (depression)
Explanation of depression- long held that depression related to low levels of serotonin within the nervous system. Serotonin in a NT, when a sense is stim. Messenger sent along the nervous system, message goes from one neurone cell to another until it reaches the right area in the CNS. Nervous system made up of many neurones which are connected by synaptic clefts where a message passes from one pre synaptic neurone to another post synaptic neurone. (NT are chemicals that carry the electrical signals between neurones. If serotonin is low, then they may be reabsorbed into pre too soon so the message isn’t passed on. Explanation is that depression is linked to a lack of serotonin but body may not respond to happy stimulus as there’s too little serotonin
Biochemical explanation of mental illness (schizo)
Schizo related to high levels of dopamine in the nervous system, causing excess dopamine to reach post synaptic neurones (dopamine is a NT)
What would a biochemical treatment aim to do
Focused on restoring higher levels of NT action e.g. treating depression by blocking the reuptake of serotonin to ensure there is enough available for messages to be carried along the nervous system. Treating schizo by blocking receptors on post to prevent an overload of dopamine reaching post cells
Genetic explanation of mental illness - genetics from parents
Certain disorders could be passed from parents to children though genetic transmission. Children could inherit a disorder or a disposition towards a disorder. Half of each child’s genes comes from each parent so is possible for one child to show a tendency but not for a sibling. Research by gottesman shows increased risk of children have two parents worth either bipolar or schizo compared to those with one parent or no parents with these disorders . Although, concordance rates are not 100% there have to be environmental or individual diffs that make people more prone to mental illness than others. Gottesman and shield found if one twin has schizo than there’s a 58% of a mz twin having it but if dz only 12%- means strong genetic component but not explained by genetics alone
Genetic explanation of mental illness- evolutionary theory
Proposed their a certain traits that may have enables people in the past to survive better than others- suggest we inherited traits that have a positive effect on our chances of survival. Explanation for phobias as people with certain fears may have had an evolutionary advantage that enabled them to survive and reproduce while those without phobias died before reproducing - could mean that phobias have a genetic basis to them. Support from ohman who gave ps electric shocks at the same time as seeing pictures of snakes, houses or human faces and it was easier to condition a fear response to the snake than the others, suggesting an inherited biological predispotion to fear snakes more
What treatment is in the early stages of research for genetic explanation for mental illness
Embryo manipulation to reduce the inheritance of mental disorders by using genetic material from biological parents is in early stages. In future, this could be the treatment of mental dosroiders that are shown to have a seeing genetic bases to them
Brain abnormality explanation for schizo
Research has found diffs in the brain structure of people with schizo. Brown et al revealed in post mortem studied comparing the brains of patients with schizo compared to those with an affective disorder. Schizophrenic had 6% lighter brains and had enlarged lateral ventricles (hollow areas in the brain), significantly thinner para hippocampal cortices (involved in episodic memory and Visuospatial processing, including scene perception). Weinberger found by doing mri scans of MZ twins but not concordant for schizo (one half had it, other half didn’t) diffs in pfc and hippocampus volume
Brain abnormality explanation of depression
Patients W depression show a smaller hippocampus volume . People W depression may have experienced stress which led to the release of cortisol- evidence cortisol can destroy hippocampal cells so then they don’t respond to stimulation normally. Could reduce the effect of serotonin. Sheline found in study of elderly women whose depression were in remission that the hippocampus was smaller on these women than those of the same age
What is a treatment for brain abnormality
Drug therapy, surgery may be used in case of brain tumours that are producing symptoms of disorders
Key research gottesman et al - disorders in offspring with two psychiatrically ill parents
Aim- to investigate in a large sample the probability of a child being diagnosed with a mental disorder if either one or both had this disorder. sample: anyone in Denmark shed 10-52 in jan 07 W a clear links to their biological parents- around 2.7 million and their parents. Method: data from psychiatric central register, identified 4 groups of people (2 parents admitted with schizo, bipolar or depression, one parents, neither parent or the general public) findings: % of ppl admitted to a psychiatric hospital when both parents had the disorder were 27.3% schizo, 24.9% bipolar, one parent W the disorder were 7% schizo, 4.4% bipolar, neither was 0.86% schizo and 0.48% bipolar and gen pop admitted is 1.12% schizo 0.63 bipolar. Some genetic overlap between schizo and bipolar (both schizo, 10.8% offspring had bipolar, both bipolar-4.8 schizo) if both parents admitted, increased likelihood of being admitted W any disorder. Age 52, few getting diagnosing of schizo but bipolar ones still being made. Conc: both parents admitted with schizo or bipolar, offspinrg are at super high risk of being admitted with a disorder themselves, info used for child bearing, adoption, counsellors (not ignorant of nazis use of genetic information for eugenics
Application- biological treatment of one specific disorder- drug therapy for depression
Aim to restore normal levels of NT action, one form is SSRIs- work by blocking the reuptake of serotonin by the pre which results in more in the synapse. More serotonin on the synapse means increased chance of sufficient serotonin reaching the post synaptic receptor sites and triggering an electrical impulse to continue down the nueronal pathway. Ssris used to treat depression and anxiety - may have side effects
