Case 6 - Depression Pathophysiology Flashcards
what is major depression defined by
the DSM-V criteria.
epidemiology of depression
10-16% of men and 20-24% of women will have some symptoms of depression
2-4% of men and 7-8% of women will have actual depression at any given time
what is the most common GP diagnosis
depression and it is present in 17% of people who present to GP in any given year
what is the mean onset age of depression
27
how many depressed patients also suffer from anxiety
50%
what are the differentials for depression
hypothyroidism
bipolar disorder
cancer or terminal diagnosis
what is the DMS-V diagnostic criteria
diagnosing depression requires a relative short history of at least 2 weeks
what is the actual criteria
at least five of the following almost every day for the last 2 weeks. number ONE and TWO are essential
- depressed mood
- loss of interest or pleasure in previously enjoyed activites
- changes in weight or change in appetite
- change in sleep - insomnia or hypersonmia
- psychomotor agitation or retardation
- fatigue or low energy
- feelings of worthlessness of guilt
- reduced concentration or decisiveness
- suicidal attempt or ideation
what else must you have to fit the criteria
symptoms cause significant distress or impair functioning
- symptoms not due to a medication, or other substance
- symtoms are not better explained by a schizophrenia spectrum disorder or psychotic disorder
- no history of a manic or hyper main episode
what are the three core symptoms
low mood
anhedonia: does not take measure from any activities patients will often withdraw from social activities
low energy levels
what is a significant weight gain
5%
what may be present
hallucinations and delusions
Schneider’s positive symptoms can occur In severe depression
what is melancholia
this is where the patient feels unable to experience any emotions at all - emotional numbers
what are the screening tools used
hospital anxiety and depression score (HADS) - despite its name is still used in general practice
Patient health questionnaire (PHG-9)
ICD-10 depression inventory (MDI)
DASS 21 or DASS 42
Also include assessment of anxiety and stress
what is psychotherapy
the process of explaining the diagnosis and its effects
what is CBT
a type of talking therapy which helps the patient to better understand their symptoms and helps them to recognise negative thought patterns, and how better to manage these thoughts, including teaching new ways of positive thinking
why should u be careful of using anti depressants in bi polar disorder
anti depressants can worsen bipolar disorder, and these patients are instead treated with mood stabilisers (lithium)
what is the aim of treatment
to induce remission
what is the first line treatment for depression
ssri’S
What are some examples of SSRI’s
fluoxetine, citalopram, sertraline, paroxetine
how long should you allow for beneficial effects
4-6 weeks
what are SSNRI’s
serotonin-noradrenaline re uptake inhibitors e.g venlafaxine. may be superior t SSRI in severe depression
what happens if medication is successful
if medication is successful and remission is achieved, it is recommended to continue medication for at least 12 months
if there are further episodes = continue treatment for 2-3 years when it is restarted
drug mechanism table
what is the typical regimen for ECTq
1-3 sessions per weeks for 8-12 weeks
what is the mechanism of ECT
It is thought that is induces grand mal type seizures and that there are necessary for antidepressant effect. it is also thought that seizures that originate in the lower brain areas are less effective that seizures that originate higher in the brain stem at reducing depression
using a high electrical current increases the therapeutic effect, but can incerease the risk of memory loss and conduction
more on ECT
uilateral treatment to the non-dominant hemisphere also reduces the risk of confusion and memory loss, but again has reduced efficacy. patients who undergo this type of ECT require 2-4 more sessions than other individuals
ECT increases the acuity of 5-HT in the cell and increases the number of post synaptic 5-HT receptors. it also enhances dopamine activity and has similar effects on noradrenaline to anti depressant drugs
what are patients given during ECT to reduce the risk of injury
a muscle relaxant
what are they given to reduce bradycardia
atropine to reduce salivary and bronchial secretion and prevent bradycardia
what are patients given before treatment begins
ventilated with 100% O2 which Is proven to reduce amnesia
where are the electrodes placed
uni lateral - one on temporal region, one near vertex
bilateral - on each temporal region
how long should depression treatment be continued for
minimum of 9 months otherwise there is a 80% risk of relapse
what are factors that point to a good outcome
large loss event precipitating the depression
normal pre-morbid personality
what is the mitochondrial dropout theory of depression
increased glucocorticoids in response to stress leads to excessive mitochondrial and subsequent neuronal death
what glional death
brain derived neurotrophic factor (BDNF) is a protein in the brain that protects neurones from damage
the neurotransmitter serotonin, noradrenaline, and to a lesser extent dopamine, all cause increased synthesis of BDNF
the end result of these factors is decreased brain activity in the prefrontal cortex, and increased activity in the limbic system
microscopically, the brains of those with chronic depression can be seen to have neuronal cell death.
macroscopically on MRI there may be seen up to 1/3 reduction inside of the hippocampus
what is the mopoaimine theory
it states that depression results of under activity of mopoaimine transmitters, and conversely that mania results from overactivity of monoamine transmitters
what is main transmitter I the monoamine theory
serotonin
where to most serotonergic neurones arise
in the Raphe area of the midbrain, and project to the limbic system and cerebral cortex
where are most noradrenaline neurones found
in the locus cereleus and lateral tegumental areas of the brain steam
where does the evidence for this theory come from
there are reduced levels of 5-HT in the brains of depressed people
- there are increased numbers of 5-HT receptors in the brains of suicidal patients
what is the hypothalamic involvement in depression
hypothalamic neurones relieve 5-HT input, which alters their output. in turn, they release CRH which controls ACTH and ultimately steroid levels. in depressed patients, cortisol levels are usually high because the hypothalamic neurones are not suppressed as much as normal,
what happens when there is excess CRH
actually causes some of the symptoms of depression, such as anxiety, reduced activity etc and CRH level are also usually raised in depression
what about neuroplasiticty and hypotrophy in depression
in depressed patients, there is often neurone loss in the hippocampus and prefrontal cortex. also many of the theories used to treat depression, and thus ultimately 5-HT itself actually promotes neurogenesis
