Biological cause and treatment of AN Flashcards
Outline how SSRIs work.
Target serotonin (in low levels associated with depression, exhaustion and lack of appetite). They block serotonin receptors increasing serotonin levels in synapse to increase cell signalling. Typically taken in tablet form, starting at lowest dosage and building up, taken for 2-4 weeks before you see a benefit. You should continue taking SSRIs for 6mo the after symptoms reduced. Aren’t given to under 18 or pregnant women. Often experience loss of sex drive, dizziness, faintness ie dapoxetine
When taking SSRIs what should you know?
1-3 tablets a day, if after 4-6 weeks symptoms are still present then try and alternative medication or increased dosage. Missing dosage will decrease the effectiveness of treatment. Can react badly with other medication ie non steroid antidepressant or antidepressant. Avoid large volume of alcohol or caffeine. Shouldn’t suddenly stop taking it as will lead to withdrawal symptoms such as sickness and diahorria.
What do NICE guidelines say about drug therapy as a form on treatment for AN
They shouldn’t be used as the first choice as they don’t help with the core symptoms of the disorder. The New Zealand guidelines 2011 recommend family CBT and dietary advice as the first choice therapies. Drug treatments should be used to treat comorbid symptoms.
Give an example of an antipsychotic drug used to treat AN
chlorpromazine led to weight gain and severe seizures
Olanzapine. An antagonist blocking D1 and D2 dopamine receptors and serotonin (SGA) reported less difficulty eating and as a consequence gained weight. less resistant to treatment and more compliant
Give strengths of drug treatment for AN
Power - SSRIs were given to 18 AN patients. 10 gained weight.
Once at a healthy weight the treatment can be carried out from home. Reduced labelling.
Requires less motivation the CBT or TE as less time consuming.
Give weaknesses of drug treatment for AN
Dally and Sargent found that it Doesn’t treat the cause of AN, just the comorbid symptoms. Likely to have re hospitalisations. So ineffective on its own, need to be paired with CBT.
Side effects - increased suicidal thoughts, depression, anxiety, weight gain. Likely to drop out and not complete treatment.
Patient compliance. Rosenhann shows how easily doctors can be deceived. Prescribe 2001pill and only 2 were actually taken
What is the application of drug treatment.
They are most effective when paired with CBT as they increase patient compliance.
AN is polygenic. what does this mean?
no single gene can explain all the symptoms of AN.
what does EPHX2 gene do. relate this to a cause of AN
It codes for an enzyme called epoxide hydrolase which regulates cholesterol metabolism and serotonin. (a NT associated with depression and anxiety). it has links with feeding and anxiety parts of the brain such as the hypothalamus which regulates hunger and the amygdala which regulates fear.
this could explain why people with AN experience anxiety around food as part of their comorbid symptoms. It could also suggest that they have a low BMI because the hypothalamus is not very good at regulating hunger so AN patients don’t eat because they don’t feel hunger in the same way as ordinary people so they aren’t motivated to eat.
what is the name of the gene that is involved in tase of food and how can this lead to AN
ITPR3 detects bitter and sweet flavours.
if the gene is faulty it could mean that AN are un motivated to eat because it doesn’t take very nice.
DAT1 is a gene linked to dopamine. explain its role and how this could lead to AN
if the gene is muted it could disrupt the dopamine pathway resulting in low motivation to eat explaining why they eat less food then they should explaining why they may have a lower BMI and comorbid symptoms
what is the name of the gene that is also present in alcohol users and drug addicts
Taq1 this is linked to obsessive characteristics which could explain why people feel addicted to weight loss and under eating as it is a compulsive drive to satisfy.
give some research to support that AN has a genetic link
Holland found that MZ twins (56%) had a higher concordance rate then DZ twins. this suggests that nature is at play. adoption studies may be better as they will not share the same environment with their parent.
heritability estimate (is a correlation between parent and child) and someone is 70% more likely to develop AN if their parent has it. genetics are passed on through the family through meiosis. however parents and offspring typically share the same environment so there is no way in knowing that nurture does not have a part in this.
Scott van sealed took DNA samples from females diagnosed with AN and controls.
he found 35 variant of ITPR3 gene and 14 EPHX2 gene. large sample of 262 ppts. however all female
what are the 3 most common classes of drugs that are prescribed to patients with AN
mood stabilisers, atypical antipsychotics, antidepressants.
SSRIS
olanzapine and atypical antipsychotic drug
what approach is given for AN treatment
multidisciplinary approach. CBT, family therapy and drugs.
weight restoration is a sign of physical improvement but not psychological wellbeing.
