Depression

Question 1

Depression

Answer 1

An affective disorder that has physical and mental symptoms

Question 2

Mental symptoms of depression

Answer 2

Low mood, low self-esteem, indecisiveness, anhedonia

Question 3

Physical symptoms of depression

Answer 3

retardation of thought & action, loss of libido, sleep disturbance, loss of appetite

Question 4

Unipolar depression

Answer 4

In unipolar depression mood only goes down

It is not associated with genetics and may or may not follow a stressful life event

Question 5

Bipolar depression

Answer 5

In bipolar depression mood alternates between depression and mania

It is associated with genetics, but no specific genes have been identified

Question 6

Cause of depression

Answer 6

The cause of depression is mostly unknown

The prefrontal cortex, amygdala and hippocampus all seem to be involved to an extent

Question 7

Monoamine theory

Answer 7

Postulated by Schildkraut in 1965

States that depression is caused by a functional deficit of the monoamine neurotransmitters noradrenaline and 5-HT

Question 8

Evidence for the monoamine theory

Answer 8

• Inhibition of NA or 5-HT can induce depression
• Most anti-depressant drugs increase the concentration of monoamines in the brain
• Reduced serotonergic and noradrenergic activity is seen in depression

Question 9

Evidence against the monoamine theory

Answer 9

• Antidepressants increase NA/5-HT concentrations within hours, but an antidepressant effect takes weeks to develop
• Cocaine blocks monoamine uptake but does not have an antidepressant effect

Question 10

Neuroendocrine theory

Answer 10

States that depression follows periods of stress

Persistent stress desensitises the negative feedback mechanism that should keep cortisol levels under control

Out of control cortisol levels then lead to depression

Question 11

Evidence for the neuroendocrine theory

Answer 11

• Individuals with Cushing’s syndrome (a disorder f cortisol) have high rates of depression
• Giving CRH to animal models can induce depression
• SSRIs seem to restore the sensitivity of the negative feedback loop by increasing the number of glucocorticoid receptors

Question 12

Evidence against the neuroendocrine theory

Answer 12

Not all depression follows stressful events

Question 13

Neurogenesis theory

Answer 13

States that depression is caused by decreased brain activity and neuronal loss in the hippocampus and pre-frontal cortex

Question 14

Evidence for the neurogenesis theory

Answer 14

• Antidepressants stimulate neurogenesis

- Stress and cortisol lead to atrophy and death of neurons as well as decreasing the rate of neurogenesis

Question 15

Animal models for depression

Answer 15

Animal models for depression are primitive and difficult to develop

• Forced-swim test
• Sucrose preference test
• Open field test
• Dark/light box
• Social defeat test