Serotonin & depression: L19

Question 1

Serotonin

1. long name
2. acts as a
3. important in many functions like
4. define mood (range)

Answer 1

1. 5-Hydroxytryptamine (5-HT)
2. neuromodulator influencing the activity of a variety of neurons throughout the brain
3. sleep, arousal, appetite, temperature, working memory, hallucinations & mood
4. manic happy sad depressed

Question 2

Serotonin pathways

1. all serotonin synthesised and released from neurons originating in the
2. the 5-TH is synthesised
3. when the neurons fire

Answer 2

1. raphe nucleus
2. in the cell body & transported to the synapses where it is stored
3. the stored 5-TH is rapidly released from the synapse

Question 3

Serotonin 5-HT receptor subtypes

1. serotonin has different effects in different brain areas depending on
2. drugs will often only activate

Answer 3

1. receptor subtypes

2. one or a few receptor subtypes, so will be MORE selective than the natural neurotransmitter

Question 4

Serotonin synthesis

1. amino acid
2. synthesis enzyme
3. break down enzyme

Answer 4

1. tyrptophan
2. tryptophan hydroxylase (TPH)
3. Monoamine oxidase (MAO)

Question 5

Depression overview

• > DSM-V diagnosis for major depression
  1. A) at least ? symptoms present for ? week period. At least one of the symptoms is either (2)
  2. symptoms NOT included

Answer 5

1. 5, for 2 week period
   (1) depressed mood
   (2) loss of interest or pleasure
2. due to a general medical condition or mood-incongruent delusions/hallucinations

Question 6

Depression DSM-V symptoms (9)

(“nearly everyday” for every symptom)

B) the symptoms cause clinically
C) the symptoms are not due to

E -> now crossed off the list

Answer 6

1. depressed mood most of the day
2. diminished interest in all/almost all activities
3. weight loss or gain. decrease in appetite
4. insomnia or hypersomnia
5. psychomotor agitation/retardation
6. fatigue/energy loss
7. feelings of worthlessness or guilt
8. diminished ability to think/concentrate or indecisiveness
9. recurrent thoughts of death, suicidal ideation

B) significant distress or impairment in social, occupational or other important areas of functioning
C) effects of a substance or general medical condition

E) the symptoms are not better account for by bereavement

Question 7

Depression vs grief

1. argument for change
2. grief rarely produces
3. it was argued that

Answer 7

1. grief-stricken patients frequently report symptoms typical of major depression

BUT

2. cognitive symptoms of depression e.g. self loathing, worthlessness, suicidal thoughts
3. it is important not to miss people with clinical depression because the symptoms were associated with grief

Question 8

Depression in family and society

1. % men, % women in their lifetime
2. 1st onset
3. cost to australia (health care)
4. family clustering, if you have depression what’s the risk to your:
   1) neighbour
   2) sibling
   3) identical twin

Answer 8

1. 5-12% men, 10-25% women
2. 15-18 (early adolescence)
3. 15b p/y
4. 1) 16%
   2) 30%
   3) >80%

= both genes & environment play a role

Question 9

Depression and serotonin

1. brain imaging studies show
2. PET studies show
3. a gene involved in the transportation of serotonin is
4. Tryptophan Depletion (TRD) induces
5. milkshake study

Answer 9

1. reduction in some types of serotonin receptors in the brain of unmedicated depressed patients
2. colour areas = serotonin receptors are relatively reduced in depressed patients
3. linked to increased risk of developing depression
4. transient depressive symptoms in recovered unmedicated patients (& in some people without depression)
5. consuming milkshake with all amino acids except Tryptophan = reduced synthesis of serotonin

Question 10

Depression & serotonin vulnerability model

4

Answer 10

1. variation in serotonin function across population
2. impaired serotonin function may be a “risk factor” leading to people being “vulnerable” to developing depression
3. depression is 5-6 x more likely after a stressful event
4. stress leads to increased release of hormones such as cortisol. serotonin function is important in managing the feedback control of the brain’s stress response

Question 11

Serotonin antidepressant (SSRI's)
drugs in this class include (4)

Answer 11

1. citalopram
2. fluoxetine
3. paroxetine
4. sertraline

Question 12

SSRIs:

1. do what to transmitters

Answer 12

1. selectively inhibit reuptake of transmitters = increases serotonin (blocks serotonin reuptake)

Question 13

SSRIs therapeutic effects

1. they are… (acting)
2. taken orally, the drug reaches the brain in
3. Therefore…

Answer 13

1. slow acting, takes weeks for any therapeutic effects
2. 1 hour after consumption & should block serotonin reuptake immediately
3. improved mood CANNOT result directly from increased serotonin around the synapse

Question 14

Theories of long latency of onset

1. altered gene expression (information to make new products e.g. enzymes)
2. shuts off
3. increases levels of

Answer 14

1. leads to slow changes in the action of different processes within a neuron (neurotransmitter synthesis/storage) or even change the structure of the neuron
2. pathologically elevated stress response underlying depressive symptoms, allowing for important neural adaptations
3. neurogenesis (birth of new brain cells) change or strengthen important mood related circuits in brain

Question 15

new brain cell growth

1. new evidence suggests that SSRI’s could promote

Answer 15

1. new brain cell growth, treating past damage and may even be “neuroprotective”, protecting against future damage associated with depression

Question 16

SSRI’s mood & personality

1. in clinical populations
2. in healthy people
3. prozac

Answer 16

1. reduces symptoms of depression
2. increases empathy and prosocial behaviour
3. • improves mood
     - better than well
     - feeling like myself for the first time
     - increases social likability

Question 17

Monoamine oxidase inhibitors (MAOIs)

1. blocks
2. what is it?
3. can (negative)
4. now used as

Answer 17

1. the breakdown of serotonin
2. powerful antidepressant drug
3. lead to lethal levels of serotonin & other neurotransmitters if ingested orally after people eat foods with too much tryptophan or tyramine resulting in “cheese syndrome”
4. last resort under strict control of diet and other medications