Chap 18: Stress and Anxiety disorders

What are the two main stress response systems?

SAM System (Sympathetic-Adreno-Medullary)

HPA Axis (Hypothalamic-Pituitary-Adrenal)

What is the primary function of the SAM system?

It provides a fast response known as 'fight or flight' by releasing epinephrine and norepinephrine.

What are the effects of the SAM system activation?

Increased heart rate, blood pressure, and energy.

HPA axis

- slower, long term response to stress

What is the pathway of the HPA Axis?

Hypothalamus → CRH → Pituitary → ACTH → Adrenal cortex → Cortisol

Key stress hormone

cortisol

What are the harmful effects of long-term cortisol exposure?

Hypertension, immune suppression, diabetes risk, and brain damage.

- higher stress = increase in BP over time

What brain structures primarily affected by chronic stress? (3)

The hippocampus, leading to decreased memory and learning.

- PFC impairment

- Amygdala hyperactivity

What are the effects of chronic stress on the brain?

Decreased hippocampal volume

Effects of prenatal stress

decrease hippocampal size

- increased anxiety risk

- premanent changes to stress responses

What does psychoneuroimmunology study?

The interaction between stress and the immune system.

What is a key idea in psychoneuroimmunology?

Stress decreases immune function and increases the risk of infections.

What are the symptoms of Posttraumatic Stress Disorder (PTSD)?

Intrusive memories, avoidance, emotional numbing, and hyperarousal.

What are some risk factors for developing PTSD?

Genetics, severity of trauma, and prior stress exposure.

What brain changes are associated with PTSD?

Decreased hippocampus volume, increased amygdala activity, and decreased prefrontal cortex control.

What are the main treatments for PTSD?

SSRIs, Cognitive Behavioral Therapy (CBT), Exposure therapy, and emerging treatments like TMS.

What are the types of anxiety disorders? (4)

Panic disorder, Generalized Anxiety Disorder (GAD), Social anxiety, and Agoraphobia.

What are common symptoms of anxiety disorders?

Excessive fear/worry, panic attacks, and avoidance behavior.

Causes of anxiety disorders

- genetics,

- environment

- conditioning

What brain changes occur in anxiety disorders?

Increased amygdala activity and decreased prefrontal cortex regulation.

What are the main treatments for anxiety disorders?

Benzodiazepines (short-term), SSRIs (long-term), CBT, and Exposure therapy.

What are the symptoms of Obsessive-Compulsive Disorder (OCD)?

Obsessions (intrusive thoughts) and compulsions (repetitive behaviors).

what are compulsions

- repetitive behaviours

=> washing

=> checking

=> counting

What is the brain basis of OCD?

Basal ganglia dysfunction with increased activity in the orbitofrontal cortex and caudate nucleus.

Causes of ADs

genetics

- infections (PANDAS - autoimmune)

What are the treatments for OCD?

SSRIs, CBT (exposure + response prevention), and severe cases may require deep brain stimulation (DBS).

What is the main takeaway regarding the SAM and HPA systems?

SAM is fast (epinephrine/norepinephrine), while HPA is slow (cortisol).

How does chronic stress affect the hippocampus?

It leads to hippocampal shrinkage and immune suppression.

What role does the amygdala play in anxiety disorders?

It is the fear center, showing increased activity in all anxiety disorders.

How does the prefrontal cortex relate to anxiety and PTSD?

It is responsible for regulation, which is decreased in both anxiety disorders and PTSD.