L19 - Anxiety and Depression Flashcards Preview

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Flashcards in L19 - Anxiety and Depression Deck (28)
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1
Q

What is anxiety disorder?

A

It is the inappropriate, excessive or anticipatory manifestation of the fear response, often to a stressor.

2
Q

What are some of the physical manifestations of anxiety disorder?

A
Autonomic reflexes
Defensive behaviours
Corticosteroid secretions
Negative emotions
These will all interfere with normal life
3
Q

What is the most common form of anxiety and what are its symptoms?

A

The most common form is GAD (general anxiety disorder) which causes some somatic and autonomic effects: sweating, tachycardia, sweating and sleep disturbance.

4
Q

What are some types of anxiety disorder?

A

Phobic anxiety
Panic disorder
PTSD
Obsessive compulsive disorder

5
Q

What is the normal mechanism behind anxiety?

A

A stimulus that causes stress causes activation of the autonomic nervous system e.g. adrenaline release
Can get release of CRH (cprticotrophin releasing hormone) from the hypothalamus which stimulates ACTH release from the pituitary. This causes the adrenal glands to release cortisol in a negative feedback loop.

6
Q

What pathology is thought to underlie mechanism for pathological anxiety?

A

It is thought to be overactivity of the HPA axis resulting in structures interacting in ways they shouldnt. This is thought to be from neuroplasticity causing new synapses between the limbic system and the hypothalmus.

7
Q

What are some of the ways that anxiety disorders can be treated?

A

Self-help
Psychological e.g. cognitive behavioural therapy
Pharmacological e.g. self medication - drinking to reduce anxiety

8
Q

What influences the choice of axiolytic drugs?

A

The symptoms of the patient

The duration of treatment needed.

9
Q

What are the main axiolytic drugs?

A

Beta blockers
Benzodiazepines
Serotonin selective reuptake inhibitors (SSRIs)

10
Q

How do beta blockers work to reduce anxiety?

A

They cause a reuction in somatic symptoms that are caused by the anxiety. They tend to be used for situational problems.

11
Q

How do benzodiazepines work to reduce anxiety?

A

They cause Increased affinity for GABAa at the GABAa receptor due to binding allosterically. This causes increased Cl- influx and enhances the inhibition of neurones. This has an affect on the limbic system as GABAa receptors are everywhere in the brain.

12
Q

What are some of the disadvantages of using benzodiazepines to treat anxiety?

A

As they are inhibitory they cause sedation.
Acute overdose can cause profound sedation and respiratory depression but not death.
If combined with alcohol then can cause death through respiratory depression.

13
Q

Why can benzodiazepines only be used for up to 4 weeks?

A

They cause tolerance to build up over time so larger doses are required to get the same effects. They also cause dependence so will cause withdrwal symptoms e.g. tremors

14
Q

How do serotonin selective reuptake inhibitors work to reduce anxiety?

A

A link has been shown between depression and anxiety, SSRIs have been shown to reduce depression. They do this through preventing reuptake of serotonin which causes increased synaptic activity.

15
Q

What are the two main types of depression?

A

Reactive (75%) and endogenous (25%)

16
Q

What are monoamines?

A

Neurotransmitters e.g. Ach and Noradrenaline

17
Q

What is the monoamine theory of depression?

A

It was predicted that depression was due to hypoacivity of monoamine neurotransmitters at synapses in the brain.

18
Q

What is the relevance of antidepressants taking 1-3 weeks to work?

A

This shows that even though these drugs immediately cause monoamine levels to increase this does not have immediate effect. Showing that depression is not purely caused by lack of monoamines.
Also amphetamines and cocaine increase 5-HT but are not antidepressants.

19
Q

What are the main treatments of depression?(non drugs)

A

Psychotherapy
Antidepressant drugs
Electroconvulsive therapy (ECT)

20
Q

What are the main antidepressant drug classes?

A

Serotonin selective reuptake inhibitors (SSRIs)
Tricyclic antidepressants
Monoamine oxidase inhibitors
Atypical antidepressants

21
Q

What is the mechanism behind monoamine oxidase inhibitors reducing depression?

A

They reduce the breakdown of monoamines at the synapses hence leading to increased excitation.

22
Q

What is the mechanism for the SSRIs?

A

They reduce the uptake of serotonin and cause immediate increases in 5-HT causing increased excitation.

23
Q

What are some of the unwanted side effects of SSRIs?

A

They cause unwanted nausea and vomiting due to interfering with 5-HT receptors in the GI tract. Also cause weight changes due to effecting 5-HT in hypothalamus.

24
Q

What is the mechanism of tricyclic antidepressants? and unwanted side effects?

A

They cause reduced reuptake of monoamines however they are antimuscarinic and sedative so are not used much anymore.

25
Q

What are some unwanted side effects of Monoamine oxidase inhibitors?

A

They develop tolerance within about 4 weeks.

Cheese reaction, stops metabolism of tyramine from diet which increases NA which increase BP.

26
Q

What is the mechanism of atypical antidepressant drugs?

A

They have various mechnisms which reduce the reuptake of monoamines. They have better adverse effect profile but still have delayed action.

27
Q

What is the new network theory of depression?

A

That increased Corticotrophin releasing factor and cortisol in the CSF cause depression and this is reduced by antidepressants.

28
Q

Why is it thought that antidepressant drugs have a delayed onset of action?

A

Due to the time taken for neuroplasticity to change the structures of the brain in response to the increased monoamines.