LC3 - anxiety, fear and panic

Question 1

generalised anxiety disorder

Answer 1

Long-lasting anxiety that is not focused on any particular object or situation
 Unspecific
 Unable to articulate the specific fear
 Unable to control worries
 Persistent muscle tension and autonomic fear reactions
 The development of headaches, heart palpitations, dizziness, and insomnia

–> co-morbidity to MDD (58%)

Question 2

fear vs anxiety

Answer 2

insensitivity to anxiolytic drugs of simple phobia in humans and active avoidance
in animals indicates that fear is distinct from anxiety

Fear:  phasic response to explicit aversive cues/stimuli  associated with avoidance of a dangerous situation
Anxiety:
 tonic response to diffuse aversive cues/stimuli
 associated with approaching a potentially dangerous situation
- higher cognitive areas involved –> reasoning

Overlap: anxiety involves modulation of pre-existing fear

Question 3

defensive distance

Answer 3

the hierarchical defense system explains the continuum between anxiety and fear –> highly individual where the anxiety and fear thresholds lie

defensive distance decreases as threats become more realistic/closer –> shift from anxiety to fear

anxiety to fear:
1. anterior/posterior cingulate (PFC)(discriminated avoidance and anticipation)
2. amygdala/hippo (active avoidance)
3. mHypothalamus (directed escape)
4. PAG (undirected escape)

• insula might also be invovled if disgust is experienced during the fear repsosnse

Question 4

Panic disorder

Answer 4

Recurrent unexpected panic attacks (PAs)
* At least one of the PAs has been followed by 1 month (or more) of
one or both of the following:

• Persistent concern or worry about additional PAs or their consequences
  (e.g., losing control, having a heart attack, going crazy).
• Significant maladaptive change in behavior related to the PAs (e.g.,
  avoidance behavior).
• mediated largely by the brainstem (PAG) and amygdala is invovled

prevalence: 2-6%

Question 5

panic attack

Answer 5

panick attack prevalence: 22.7%
An abrupt surge of intense fear or intense discomfort that reaches a peak within
minutes, and during which time four or more of the following symptoms occur.
The abrupt surge can occur from a calm state or an anxious state:
1. Palpitations, pounding heart, or accelerated heart rate
2. Sweating
3. Trembling or shaking
4. Sensations of shortness of breath or smothering
5. Feeling of choking
6. Chest pain or discomfort
7. Nausea or abdominal distress
8. Feeling dizzy, unsteady, lightheaded, or faint
9. Chills or heat sensations
10. Paresthesias (numbness or tingling sensations)
11. Derealization (feelings of unreality) or depersonalization (being detached from oneself)
12. Fear of losing control or going crazy
13. Fear of dying

Question 6

Co2 in brain

Answer 6

1. Co2+H2O –> H+ + HCO-
2. pH goes down –> [H+] > 0.1 uM leads to death

• is used to induce panic attacks which is relevant for treatment and studying –> false alarm hypothesis (amygdala as chemosensor ACID1)

Question 7

5-HTT and Co2 panic sensitivity

Answer 7

the vulnerability to CO(2) is moderated by differences in serotonin (5-HT) activity, caused by a functional polymorphism in the promoter region of the 5-HT transporter (5-HTTLPR) gene –> Subjects with the SL and SS genotype reported less fear than LL subjects

significant relationship between methylation at the regulatory region of the gene encoding the 5-HTT and the reactivity to a 35% CO2 inhalation in PD patients.

• Inhaling CO2 activates the brainstem in PD patients. –> brainstem is important structure in sensing changes in pH and triggering adaptive responses. (Amygdala not needed but is involved!!–> lesion study)

1. An increase in CO2 associated with a decrease in pH activates medullary and midbrain 5-HT neurons to restore the acid–base homeostasis.
2. Medullary 5-HT neurons project to respiratory nuclei –> thereby driving respiratory adaptations.
3. Midbrain 5-HT neurons project to the forebrain, mediating emotional states such as arousal and anxiety