Antidepressants Flashcards
What are some of the feelings in depression?
Anhedonia - ability to feel pleasure Grief and guilt Self-harm Psychomotor retardation Vegetative symptoms (Sleep, appetite, stress hormones)
What are some symptoms of depression?
- Persistent sad, anxious, or ‘empty’ mood.
- Feelings of hopelessness, pessimism.
- Feelings of guilt, worthlessness, helplessness.
- Loss of interest or pleasure in hobbies and activities that were once enjoyed.
- Thoughts of death or suicide.
Decreased energy, fatigue, being ‘slowed down’
Restlessness, irritability
Insomnia, early-morning awakening or oversleeping,
Appetite and/or weight loss or overeating and weight gain.
Persistent physical symptoms that do not respond to treatment such as headaches, digestive disorders and chronic pain
What is MAO?
Monoamine Oxidase Inhibitors
How was MAO found as a drug for depression?
Discovered by chance when Iproniazid when being used to treat tuberculosis. They saw greater vitality (Healey, 1999)
What kind of drug is Iproniazid?
A monoamine agonist
What does a monomaine agonist (like Iproniazid) do?
Increases the levels of monoamines by inhibiting the activity of the enzyme monoaminoxidase (MAO)
What are monoamines?
Noradrenaline, dopmaine and serotonin
What happens when a drug effects the enzymatic process?
It increases the availability of neurotransmitters in synaptic gap, so then they can bind to post synaptic receptors again.
What serious side effects are associated with MAO?
Cause liver damage
Dysfunction in blood pressure controls
How does MAO affect blood pressure?
Noradrenaline is involved in blood pressure control so an increase in noradrenaline will raise blood pressure.
Nonspecific MAO blockers influence MOA-A centrally and in periphery, leading to increase in noradrenaline, increase in blood pressure.
What is dietary tyramine?
An indirect noradrenaline agonist found in foods, such as mature cheese, red wine, pickled herring and yeast like marmite.
These indirectly increase the availability of noradrenaline so if the enzyme is inhibited then there is an increase in blood pressure and a hypertensive crisis.
What are tricyclic antidepressants?
Drugs that block the reuptake of both serotonin and noradrenaline, thus increasing their levels in the brain.
How were tricyclic antidepressants found to help depression?
Patients diagnosed with depressive psychosis showed marked improvement in their general state within a few weeks (1957).
What are some side effects of tricyclic antidepressants?
Dry mouth (salivary gland activation) Impaired muscular control in the eye (blurred vision) Tachycardia (irregular heartbeat), constipation etc.
What is Ashcroft & Eccleston’s (1960) take on the monoamine hypothesis?
First theory that serotonin low in depression
Low concentration of serotonin, 5HT or its main metabolite, 5-HIAA were found in autopsy.
Studied brains of suicide victims and cerebrospinall fluid in depressed patients
What is Axelrod’s (1961) take on the monoamine hypothesis?
Discovered monoamine reuptake by pre-synaptic neurons and tricyclic antidepressants block this mechanism
Dismissed 5HT as unimportant.
What is Schildkraut’s (1965) take on the monoamine hypothesis?
The catecholamine hypothesis of affective disorders
The noradrenaline hypothesis of depression was the leading idea that guided research.
What is the evidence that depression is associated with monoamine neurotransmitter deficiency?
Certain drugs that depleted these neurotransmitters could induce depression (reserpin)
Known antidepressants at the time boosted these neurotransmitters and alleviated depression.
What are the main serotonin pathways in depression?
Transmission from both the caudal raphe nuclei and rostal raphe nuclei is reduced in patients with depression.
How can serotonin pathways alleviate depression?
Increasing levels of serotonin in these pathways, and reducing reuptake and thus increasing serotonin function.
what are the behavioural functions of serotonergic projection from the raphe to the frontal cortex?
Regulating mood
what are the behavioural functions of serotonergic projection from the raphe to the basal ganglia?
Help control movements as well as obsession and compulsion.