Ch13: Antidepressants

Question 1

Monoamine theory of depression

Answer 1

Depression is a result of diminished activity in the 5-HT system in the brain

Question 2

Glucocorticoid theory of depression

Answer 2

Structural changes in HPA axis leads to a loss of balance between inhibition and excitation of the stress system, resulting in heightened stress hormone release.

Heightened HPA-axis activity and resulting elevation of hormone levels increases risk of depression and suicide.

Structural changes in HPA axis -> loss of balance between inhibition & excitation of stress system -> heightened stress hormone release -> depression

Question 3

Monoamine oxidase inhibitors (MAOIs)

Answer 3

• First antidepressant ever (i.e. iproniazid) in late 1950s
• Inhibit the activity of monoamine oxidase so that molecules of DA, NE, and 5-HT that float freely are available for vesicle storage and later release
• Increase availability & activity of DA, NE, 5-HT

Question 4

Tricyclic antidepressants (TCAs)

Answer 4

• Also first-gen antidepressant (i.e. imipramine)
• Safer than early MAOIs
• Block reuptake transporter proteins on terminal buttons of 5-HT and NE neurons
• After they’re released into the cleft by action potential, their reuptake is inhibited and their duration of action on the postsynaptic cell is prolonged

Question 5

Selective serotonin reuptake inhibitors (SSRIs)

Answer 5

• Second-gen antidepressant (i.e. fluoxetine, Prozac)
• Safer, less side effects
• Diminish the ability of presynaptic cells to reabsorb and recycle 5-HT
• Causes a buildup of 5-HT at synapses and prolongs postsynaptic receptor stimulation

Question 6

Serotonin and norepinephrine reuptake inhibitors (SNRIs)

Answer 6

• Third-gen antidepressant (i.e. bupropion, Wellbutrin)
• Enhancing NE activity is helpful for those who have fatigue & loss of energy
• Block reuptake of 5-HT, NE, and sometimes DA

Question 7

Effects of antidepressants on sleep

Answer 7

• MAOIs cause insomnia or sedation
• TCAs cause drowsiness
• Reduce REM sleep, which can help to improve symptoms
• Bupropion increases REM sleep, produces insomnia

Question 8

Subjective effects of antidepressants

Answer 8

• Similar to antipsychotics at low doses, causes feelings of tiredness, apathy, weakness
• Does not produce euphoric/ pleasant effects