Capter 12 Flashcards
What is the leading cause of disability worldwide?
depression
What % of men experience depression in a year? women?
men = 4.7% women = 8.5%
what is the lifetime risk of depression?
~16%
What are the weaknesses of the ‘chemical imbalance’ theory of depression?
- no consistent evidence to show that there is any deficiency of any of the neurotransmitters in individuals with depression
- studies in which the levels of these transmitters have been chemically reduced for a brief period of time have not consistently shown to produce depression in individuals
- neurotransmitter changes occur soon a er drug administration, but the clinical antidepressant effect develops more slowly
What is the neurogenic theory of depression?
(1) existing neurons are able to “repair” or “remodel” themselves and
(2) the brain is capable of making new neurons
This theory implies that depression is a neurodegenerative condition that affects the hippocampus
What is neurogenesis?
The birth of new neurons
What are some additional theories of depression?
- hypothalamic-pituitary-adrenal (HPA) axis dysfunction theory
- the inflammation theory
- the stress generation theory
Which theory of depression has been shown to sufficiently explain the diverse symptom presentation of depression across individuals?
none
What are neurotrophins?
protiens that are important for the normal development and health of the nervous system
What is BDNF?
a neurotrophin called brain-derived neurotrophic factor
What is the monoamine hypothesis?
is it supported?
Rooted in the fact that
- some drugs that deplete monoamines result in depression
- all drugs that improve depression increase one or more of these neurotransmitters
no
What is BDNF?
Brain Derived Neurotrophic Factor: a protien involved in keeping neurons viable and under conditions of stress is suppressed
encoded by the BDNF gene
What is the HPA axis theory of depression?
dd
What are the mechanisms of action of TCAs?
- They block the presynaptic reuptake transporter for norepinephrine and serotonin.
- TCAs block postsynaptic receptors for histamine and acetylcholine. Such blockade accounts for most of the side effects of this class of drugs.
What are the 3 clinical limitations of tricylic antidepressants?
- Slow onset of action
- Lots of effects on the CNS resulting in my side effects
- they are cardiotoxic and potentially fatal in OD
What is Monoamine oxidase (MAO)?
an enzyme that regulates the amount of monoamine neurotransmitters (norepinephrine, dopamine, and serotonin) in the body and the brain
Why is it important that a patient on the 3 classic MAOs must continue to observe dietary restrcitions for 10-14 after they stop taking them?
because they are irreverable: their bond with monoamine oxidase is permanent meaning that the enzyme function only goes back to normal when new enzyme has been synthesized
What are heterocyclic antidepressants?
also known as atypical antidepressants
they were developped in an effort to find structurally different agents that might overcome some of the disadvantages of the TCAs
What are 2 advantages of SSRIs?
- Because of their receptor selectivity, SSRIs exert few anticholinergic or antihistaminic side effects.
- are not fatal in overdose because they are devoid of the cardiac toxicity produced by TCAs.
What are 4 concerns with SSRIs?
- The treatment-resistant patient
- Serotonin syndrome
- SSRI discontinuation syndrome
- SSRI-induced sexual dysfunction
What is Serotonin syndrome?
Accumulation of serotonin leads to a cluster of responses, including cognitive disturbances, such as disorientation, confusion, and hypomania; behavioral agitation and restlessness; autonomic nervous system dysfunctions, such as fever, shivering, chills, sweating, diarrhea, hypertension, and tachycardia; and neuromuscular impairment, such as ataxia, increased reflexes, and myoclonus. Visual hallucinations have even been reported.
What is SSRI Discontinuation Syndrome?
A syndrome that develops when SSRIs are suddently disconincued
6 core symptoms: (FINISH)
- Flulike symptoms (fatigue, lethargy, myalgias, chills, headache)
- Insomnia (sleep disturbances, vivid dreams)
- Nausea (gastrointestinal symptoms, vomiting, diarrhea)
- Imbalance (dizziness, vertigo, ataxia)
- Sensory disturbances (sensation of electric shocks in the arms, legs, or head)
- Hyperarousal (anxiety, agitation)
