L11: Depression Flashcards
What is SAD (seasonal affective disorder) and how is it treated?
- SAD is a type of depression with seasonal patterns, affecting more females than males.
- Treatment: Light therapy is used to compensate for reduced natural sunlight during the winter
What is bipolar depression, and how is it treated?
- Bipolar depression involves oscillations between depressive and manic episodes.
- Treatment: Mood stabilizers help manage mood swings between depression and mania.
What is unipolar depression, and what are some common characteristics?
- Unipolar depression = most common form, more prevalent in females.
- Common characteristics: Persistent depressed mood, lack of interest in pleasurable activities.
- Treatment: Psychotherapy, antidepressants, and ECT for severe cases
What are the criteria for a major depressive episode?
- Major depressive episode: Depressed mood, lack of interest in activities for ≥2 weeks.
- Additional symptoms: Changes in appetite, sleep disturbances, fatigue, worthlessness, difficulty concentrating, thoughts of death or suicide
What are the neurochemical factors associated with depression?
- Noradrenaline - found in locus coeruleus & Raphe nucleus, plays a role in motivation.
- Serotonin: located in the dorsal & ventral raphe, influences mood, anxiety & sleep.
- HPA axis: Involves the hypothalamus, cortisol levels are elevated in individuals with depression, affecting growth and prolactin levels.
What is the monoamine hypothesis of depression?
- Monoamine hypothesis: Depression results from a deficiency of monoamine neurotransmitters, while mania is caused by an excess of the same neurotransmitters
How does the malfunction of the neurotrophic pathway relate to depression?
- evidence suggests reduced BDNF levels OR malfunction of TrkB (BDNF receptor) in depression - affecting the neurotrophic pathway
How do antidepressants affect neurochemistry and brain structure in depression?
- Antidepressants reduce NMDA receptor activation & glutamate release
- can both depress & facilitate the depressive mood
- Antidepressants may prevent long-term changes in the brain by stimulating neurogenesis & ↑ BDNF levels.
what are TCAs?
- Tricyclic Antidepressants
-one of the oldest classes of antidepressants.
what are SSRIs?
- Selective serotonin reuptake inhibitor
- most commonly prescribed antidepressants
what are SNRIs?
Serotonin-Norepinephrine Reuptake Inhibitors
SNRIs target both serotonin and norepinephrine reuptake
What are NaSSAs?
Noradrenaline-Serotonin Specific Antidepressants (NaSSAs):
NaSSAs enhance noradrenaline and serotonin neurotransmission
What is the mechanism of action of TCAs?
- Block reuptake of serotonin and norepinephrine
- increasing their availability in synapses
Name some TCAs
Amitriptyline, Imipramine, Nortriptyline
How long does it typically take for TCAs to show improvement in symptoms?
2-4 weeks
What are some common side effects of TCAs?
- Dry mouth
- constipation
- blurred vision
- drowsiness
- potential for cardiac side effects
How do SSRIs work to alleviate depression? Discuss their mechanism of action
- SSRIs inhibit the serotonin reuptake process, allowing more serotonin to remain in the synapse
- increase in serotonin levels in synapse enhances serotonin signalling & transmission between nerve cells.
- prolonged presence of serotonin in the synapse= improved communication between nerve cells involved in mood regulation
name some SSRIs
Fluoxetine (Prozac), Sertraline (Zoloft), Escitalopram (Lexapro)
How long does it usually take for SSRIs to show significant improvement?
Typically takes 2-6 weeks
What are some common side effects associated with SSRIs?
- Nausea
- sexual dysfunction
insomnia - potential for serotonin syndrome
What neurotransmitters do SNRIs target and how?
Block the reuptake of both serotonin AND norepinephrine
Name some SNRIs used as antidepressants
Venlafaxine (Effexor), Duloxetine (Cymbalta), Desvenlafaxine (Pristiq)
How long does it take for SNRIs to demonstrate noticeable effects?
- may take 2-6 weeks
What are some potential side effects of SNRIs?
- Nausea, headache, increased blood pressure, and potential for withdrawal symptoms
How do NaSSAs work to treat depression?
- enhance noradrenaline & serotonin neurotransmission by blocking specific receptors
name some NaSSAs used as antidepressants
Mirtazapine (Remeron), Mianserin (Lantanon)
How long does it typically take for NaSSAs to take effect?
may take several weeks
What are some common side effects associated with NaSSAs?
- Sedation, weight gain, dry mouth, and potential for agranulocytosis (rare)
What are some common side effects of antidepressants?
include nausea, dry mouth, dizziness, and headache
What unwanted effect is commonly associated with antidepressants?
- Some antidepressants may cause sexual dysfunction
- leading to decreased libido and difficulties achieving orgasm
According to the monoamine hypothesis, what is the cause of depression?
- caused by a functional deficit of monoamine transmitters (serotonin, norepinephrine, dopamine)
What is believed to cause mania, as per the monoamine hypothesis?
caused by a functional excess of the same monoamine NTs
How do antidepressants work to alleviate depression based on this monamine hypothesis?
- Antidepressants aim to restore the balance of these neurotransmitters in the brain to alleviate symptoms of depression
What is the Neuroendocrine Theory of Depression?
- suggests that abnormalities in the hypothalamic-pituitary-adrenal (HPA) axis - which regulates body’s stress response - play role in development of depression
- theory highlights the dysregulation of cortisol (a stress hormone) and other neuroendocrine factors in depression
What is the Neuroplasticity Theory of Depression?
- proposes that depression is linked to impaired neuroplasticity
- which refers to the brain’s ability to reorganize and form new neural connections in response to experiences and learning
- suggests that depression may result from reduced neurogenesis (formation of new neurons) and synaptic plasticity in specific brain regions
