Lecture 17&19: mental illness, mood/anxiety disorders Flashcards
What is mental illness?
- health condition mediated by the brain
- characterized by alterations in thinking, mood, or behavior (or some combination)
- associated with distress and/or impaired functioning, including disability, pain, and/or death
Why is addiction not seen as a mental illness by some people?
- some people view addiction as a choice, whereas many other mental disorders are viewed as illnesses/diseases
How did the use of antibiotics to treat the mania caused by syphilis helped to change the opinion of people about mental illness?
- antibiotics were already used to treat other things that were accepted as diseases because they were ‘physical’
- when we found out that an antibiotic could treat mental illness, people realized that a psychiatric disorder was as real of a disease as a physical one, and it could be treated by physicians with medications
What are mood disorders? List 3 of them.
Disorder of emotions!
- major depressive disorder
- bipolar disorder
- cyclothymic disorders
- depression induced by substance use
- seasonal affective disorder (SAD)
In the case of depression, it has been shown that there is a loss of hippocampal volume and an increased activation to the amygdala. How do these changes affect the levels of cortisol and how is cortisol related to depression?
- the amygdala triggers the hypothalamus to start the HPA axis stress response, which ultimately releases cortisol. increased activation of amygdala = higher cortisol
- increased sensitivity to negative stimuli ^
- chronic high cortisol levels damage the hippocampus, which is part of the negative feedback response. with less hippocampal volume, it is less effective = higher cortisol
- ‘normal’ (not atypical) depression is caused by high cortisol levels
It has been hypothesized that allergies might play a role in major depressive disorder. Indicate 3 reasons supporting this hypothesis
- rates of allergies are higher in patients with depression
- during spring, there’s an increase in hospital admissions and suicide rates
- pollen increases production of cytokines
–> cytokines activate the HPA axis
–> cytokines also take away tryptophan (needed for 5-HT)
What is anxiety?
Anxiety disorder?
- normal reaction to stress
- anxiety disorder:
- excessive & disproportionate fear/anxiety or avoidance of perceived threats
Fear vs anxiety?
Fear → feeling evoked by threat or impending danger
Anxiety → anticipation of real or imagined future threat of danger
How is FGF2 involved in anxiety? What is the use of knowing that FGF2 is involved in anxiety?
- potential biomarker (gene) for anxiety
- lower FGF2 = higher anxiety
- may regulate anxiety via the HPA axis
- it’s important for supporting the genetic hypothesis/basis for anxiety disorders
- also supports that anxiety is a disease
Anxiety disorders and major depressive disorders have high concordance. Explain the common mechanism to both diseases
- both caused by / associated with irregularities / dysfunctions in the HPA axis
- both involve increased stress response
How does the dysregulation of GABA neurotransmission in the brain contribute to anxiety disorders?
- dysregulation of GABA elevates reactivity of the amygdala –> increased sensitivity to stress –> increased cortisol levels –> anxiety disorder
How do benzodiazepines work?
- GABA agonists
- facilitate binding of inhibitory NT GABA to its receptors