Depression Flashcards
Has there been any significant difference found between antidepressants and placebo?
No
What are the two types of depression?
Unipolar and bipolar
Which is the most common form of depression?
Unipolar
What is unipolar depression?
Mood swings in one direction
What causes unipolar depression?
75% reactive (ie environmental)
25% endogenous (ie genetic)
What is bipolar depression?
Oscillation between depression and mania
What is mania?
Excessive exuberance, enthusiasm, self confidence, impulsive actions, aggression, irritability and delusions of grandeur
What is type I bipolar (and its prevalance)?
More mania episodes with or without depression (1% population)
What is type II depression (and its prevalence)?
Hypomania and episodes of major depression (0.6% of population)
When does bipolar depression onset?
In adult life
To get a depression diagnosis what do you need?
5 or more symptoms during the same two week period (one being depressed mood or loss of interest or pleasure)
What is the list of depression symptoms?
- Depressed mood most of the day, nearly every day
- Markedly diminished interest or pleasure in all or most activities most or the day, every day
- significant weight loss or gain (not meaning to) or decrease or increase in appetite nearly every day
- A slowing down of thought and a reduction of physical movement
- fatigue or loss of energy nearly everyday
- feelings of worthlessness or excessive or inappropriate guilt nearly every day
- Diminished ability to think, concentrate or decide nearly every day
- Recurrent thoughts of death, suicidal intention (with or without a specific plan)
What are the emotional symptoms of depression?
Apathy, pessimism, negativity
Low self esteem, guilt
Loss of motivation
Indecisiveness
What are some other biological symptoms of depression?
Reduced activity
Loss of libido
Sleep disturbance
Loss of appetite
What are some other disorders depression is often associated with?
Terminal/ chronic illnesses Thyroid dysfunction Neurological disease Stroke Drug abuse Parkinsons Anxiety
What are the two major theories of depression?
Monoamine and neuroendocrine
What is the evidence for the monoamine theory?
Overall reduced activity of central noradrenergic and serotonergic symptoms
Reserpine depletes brain of NA and serotonin which induce depression
What is the evidence against the monoamine theory?
It’s difficult to show deficits in brain
Most antidepressant drugs take several weeks to show a theraputic effect but amine increase is acute
Some antidepressants dont affect monoamines at all
Cocaine blocks amine uptake but has no antidepressant effect
Decreased serotonin in bipolar is linked to aggression not depression
What is the methodology of the neuroendocrine theory?
(Basically just HPA axis)
NAergic and serotonin neurons input to the hypothalamus
Hypothalamus releases CRH
CRH acts on pituitary to release ACTH
ACTH acts on adrenal cortex to release cortisol
What is the effect of childhood neglect on depression?
Decreased hippocampal feedback in depression
Tactile stimulation just after birth activates 5HT pathways to the hippocampus that trigger long lasting increase in expression of glucocorticoid receptor gene -> increase in hypothalamic glucocorticoid receptors
What do SSRIs increase?
Glucocorticoid receptors in the hippocampus
What is the effect of the amygdala on the HPA axis?
Stimulates
What is the effect of the hippocampus on the HPA axis?
Inhibits
What is the neuroplasticity and Neurogenesis theory of depression?
Evidence of neuronal loss and decreased neuronal activity in hippocampus and prefrontal cortex
Antidepressants promote neurogenesis in those bits
5HT promotes neurogenesis in development
Why does the monoamine theory of depression need to be extended?
Imbalances between neurotransmitters producing long term alterations in gene expression, growth factors and neurotransmitters
Does brain atrophy happen in depression?
There is some evidence, yes
What are the differences between PET images of neuronal activity?
Normal have significantly more signals
What is CBT based on?
Helping depressed individuals to recognise and change their negative cognitive processes and thus improve mood and counterproductive behaviours
What is interpersonal therapy based on?
The assumption that depression is multi factorial but that interpersonal difficulties play a central role in maintaining depressive symptoms
What are the pharmacological treatments for depression?
Tricyclic antidepressants
Monoamine oxidase inhibitors
Selective serotonin reuptake inhibitors (SSRIs)
How do SSRIs work?
Selectively inhibit reuptake of serotonin in the synapse
How do monoamine oxidase inhibitors work?
Increase the amount of noradrenaline
What are MAOI associated with?
Food and drug interactions (specifically cheese and wine)
What does tyramine do?
Acts as indirect sympathomimetic and increases noradrenaline release
What are some side effects of MAOIs?
NA accumulation can lead to headaches, intracranial haemorrhages, BP elevation and severe hypertension
They also reduce metabolism of opioid analgesics and alcohol
What are the main theraputic effects of tricyclic antidepressants?
NA and 5HT reuptake inhibitor (also initially increases them in the synaptic cleft)
What are some side effects of SSRIs?
Insomnia, sexual dysfunction (5HT2)
Nausea, GI distress and headache (5HT3)
Why are SSRIs safer and better tolerated?
Lack of anti cholinergic effect and no cardiotoxicity with a broader theraputic profile
What are some possible future antidepressant types?
Drugs affecting monoamine transmission, affecting ion channels cortisol and NK1/2 receptor antagonists and M1/M2 agonists
What are problems with antidepressants?
Side effects,
toxic with overdose,
delayed effects,
non-responsive in certain people
What are the treatments for bipolar disorder?
Lithium
How does lithium work?
Inhibits enzymes involved in signal transduction
