Lecture 17&19: mental illness, mood/anxiety disorders

Question 1

What is mental illness?

Answer 1

• 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

Question 2

Why is addiction not seen as a mental illness by some people?

Answer 2

• some people view addiction as a choice, whereas many other mental disorders are viewed as illnesses/diseases

Question 3

How did the use of antibiotics to treat the mania caused by syphilis helped to change the opinion of people about mental illness?

Answer 3

• 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

Question 4

What are mood disorders? List 3 of them.

Answer 4

Disorder of emotions!

• major depressive disorder
• bipolar disorder
• cyclothymic disorders
• depression induced by substance use
• seasonal affective disorder (SAD)

Question 5

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?

Answer 5

• 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

Question 6

It has been hypothesized that allergies might play a role in major depressive disorder. Indicate 3 reasons supporting this hypothesis

Answer 6

1. rates of allergies are higher in patients with depression
2. during spring, there’s an increase in hospital admissions and suicide rates
3. pollen increases production of cytokines
   –> cytokines activate the HPA axis
   –> cytokines also take away tryptophan (needed for 5-HT)

Question 7

What is anxiety?
Anxiety disorder?

Answer 7

• normal reaction to stress
• anxiety disorder:
  
  • excessive & disproportionate fear/anxiety or avoidance of perceived threats

Question 8

Fear vs anxiety?

Answer 8

Fear → feeling evoked by threat or impending danger
Anxiety → anticipation of real or imagined future threat of danger

Question 9

How is FGF2 involved in anxiety? What is the use of knowing that FGF2 is involved in anxiety?

Answer 9

• 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

Question 10

Anxiety disorders and major depressive disorders have high concordance. Explain the common mechanism to both diseases

Answer 10

• both caused by / associated with irregularities / dysfunctions in the HPA axis
• both involve increased stress response

Question 11

How does the dysregulation of GABA neurotransmission in the brain contribute to anxiety disorders?

Answer 11

• dysregulation of GABA elevates reactivity of the amygdala –> increased sensitivity to stress –> increased cortisol levels –> anxiety disorder

Question 12

How do benzodiazepines work?

Answer 12

• GABA agonists
• facilitate binding of inhibitory NT GABA to its receptors