Case 5: Benjamin Nuri - Anxiety Disorders

ANS: Description

Part of PNS

Regulate involuntary + visceral body functions

Divided into SNS + PSNS

SNS

From thoracolumbar regions

SNS: Axons

Preganglionic: Short + myelinated cholinergic fibres

• Cell bodies in spinal cord lateral horn

• Synapse:

  • Paravertebral ganglia (sympathetic trunk)

    • Same level

    • Superior + inferior

  • Prevertebral ganglia

  • Adrenal medulla

Postganglionic: Long + unmyelinated adrenergic fibres

• Exit ganglia → Innervate organs

  • Paravertebral: Blood vessels, glands, smooth muscles, pelvis

  • Prevertebral: Abdominal

PSNS

From craniosacral regions

PSNS: Axons

Preganglionic: Long + myelinated cholinergic fibres

• Cell bodies in CN nuclei and spinal cord lateral horn

• Synapse in ganglia

  • Close to/inside organs

Postanglionic: Short + unmyelinated cholinergic fibres

• Exit ganglia → Innervate organs

SNS Activation

Fight-or-flight

Eyes: Mydriasis

Salivary Glands: Increase mucinous secretions

Sweat Glands: Increase sweat secretion

Heart:

• Increase HR + contraction

• Vasoconstriction

Lungs:

• Bronchodilation

• Hyperventilation

Gastric Organs:

• Decrease motility + insulin release (a2)

• Increase glucose production + insulin release (b2)

Bladder: Increase sphincter tone + detrusor muscle relaxation (hold urine)

Reproductive Organs: Increase uterine contraction + ejaculation

Adrenal Glands: Increase cortisol production

PSNS Activation

Rest-and-digest

Eyes: Miosis

Salivary Glands: Increase serous secretions

Heart:

• Decrease HR + contraction

• Vasodilation

Lungs: Bronchoconstriction

Gastric Organs:

• Increase motility, insulin release, glycogen production

• Decrease glucose production

Bladder: Decrease sphincter tone + detrusor muscle contraction (empty bladder)

Reproduction Organs: Erection

Adrenal Glands: Decrease cortisol production

SNS Activation Sensations

Uncomfortable physical sensations = Survival

Improve “readiness” to response to threats/stressors

Smoke Detector Principle: Low danger threshold = Trigger SNS activation

• Repeated encounters = Further decrease threshold

Anxiety Disorders: Description

Conditions characterized by excessive + persistent fear, anxiety, worry, and avoidance

• Fear: Emotional response to threat

• Anxiety: Anticipation of future threat

• Worry: Apprehensive expectation

Anxiety Disorders: Types

Generalized Anxiety Disorder (GAD): Excessive + persistent anxiety for ≥ 6 months

Panic Disorder: Recurrent panic attacks + ≥ 1 month of persistent worry about attacks

Phobias: persistent + intense fear of object/situation

Anxiety Disorders: Epidemiology

Most common mental health disorder in children + adolescents

Risk Factors…

• Female

• Genetics

• Environmental

  • Violence

  • Trauma

  • Chronic stress

  • Low SES

Anxiety Disorders: Etiology

Idiopathic (40%)

Biological

• Serotonin system disruption

• GABA dysfunction

Environmental

• Stress

• Smoking

• Psychological trauma

• Substance use

Other medical conditions

• Hyperthyroidism

• Asthma

Anxiety Disorders: Pathophysiology

ANS dysfunction

• SNS activation + PSNS withdrawal

• Interoceptive conditioning

Prefrontal cortex + limbic system dysfunction

Anxiety Disorders: SNS Activation + PSNS Withdrawal

Low danger threshold = Normal stimuli trigger abnormal physical response (worry, freezing, fighting, flighting)

Anxiety Disorders: Interoceptive Conditioning

Maintain symptoms

1. Stimulus trigger bodily sensations

2. Perceive sensations = Threat = Activate SNS

3. More bodily sensations = Confirm threat

• Amygdala associates sensation with anxiety response

• Conditioning: Experience stimulus again = Anxiety response

4. Behavioural responses

• Avoidance

• Excessive monitoring

• Seeking reassurance

Anxiety Disorders: Prefrontal Cortex + Limbic System Dysfunction

Prefrontal cortex + limbic system detachment = Decreased GABA + serotonin = Decreased brain inhibition = Increase anxiety

GAD: Clinical Presentation

Prolonged + excessive worrying

Nervousness

Restlessness

Irritability

Difficulty concentrating

Insomnia + fatigue

Panic Disorder: Clinical Presentation

Recurrent panic attacks

• Peak within mins

• Somatic symptoms

  • Palpitations

  • Chest pain/tightness

  • Tremor

• Cognitive symptoms

  • Fear

• Persisting worry of future attacks

Anxiety Disorders: DDx

Psych conditions

• PTSD

• OCD

• Mood disorders

Medical conditions

• Substance withdrawal

  • Alcohol

  • Benzos

  • Opioids

• CVD

GAD: Diagnostic Criteria

DSM-5

Excessive anxiety + worrying ≥ 6 months

• Difficult to control

≥ 3 (adults) OR ≥ 1 (children) for ≥ 6 months

• Sleep disturbances

• Muscle tension

• Irritability

• Difficulty concentrating

• Easy fatigue

• Restlessness

Significant distress + impairment

Not from substance use or other condition

Panic Disorder: Diagnostic Criteria

DSM-5

≥ 1 panic attack: Sudden-onset episode of intense fear with ≥ 4 of…

• Palpitations

• Tachycardia

• Diaphoresis

• Trembling

• SOB

• Choking sensation

• Chest pain

• Abdominal distress

• Dizziness

• Chills or heat sensation

• Parasthesias

• Derealization/depersonalization

• Fear of losing control/dying

≥ 1 month worrying for next attack

Behavioural changes to avoid attack

Not from substance use or other condition

Phobias: Diagnostic Criteria

DSM-5

Fear of specific object/situation

• Immediate

• Avoidance

• Disproportionate to actual danger

Persist for ≥ 6 months

Anxiety Disorders: Investigations

Blood tests

• TFTs

• CBC

• Metanephrines → Pheochromocytoma

Urine test

• Drug screen

• Urinalysis

ECG

Anxiety Disorders: Treatment/Management

Nonpharmacological

Pharmacological

Anxiety Disorders Management: Nonpharmacological

CBT: First-line

Phobias: Exposure therapy

Anxiety Disorders Management: Pharmacological

Antidepressants

Anxiolytics

Benzodiazepines

Antidepressants

SSRIs

SNRIs

TCAs

Antidepressants: SSRIs

Ex: Excitalopram, paroxetine, sertraline

MOA: Inhibit serotonin reuptake

Indications:

• First-line → GAD, panic disorder

• Second-line → Phobias

Adverse Effects:

• Headache

• GI symptoms

• Sexual dysfunction

• SS

Antidepressants: SNRIs

Ex: Dulozetine, venlafaxine

MOA: Inhibit serotonin + norepinephrine reuptake

Indications:

• First-line → GAD, panic disorder

Adverse Effects:

• Dyslipidemia

• Sleep disturbances

• SS

Antidepressants: TCAs

Ex: Imipramine

MOA: Inhibit serotonin + norepinephrine reuptake

Indications:

• Second-line → GAD, panic disorder

Adverse Effects:

• Cardiotoxicity

• SS

Anxiolytic

Ex: Buspirone

MOA: Partial 5-HT1A receptor agonist

Indications:

• Second-line → GAD

Adverse Effects:

• Headache

• Dizziness

• Nausea

• Seizures (chronic use)

Benzodiazepines

Ex: Alprazolam, diazepam

MOA: Bind + open GABA-A receptors = Increase inhibitory effects

Indications:

• First-line → Phobias

• Second-line → GAD (short-term), panic disorder

Adverse Effects:

• Motor impairment (coordination)

• Cognitive impairment (confusion, amnesia, drowsiness)

• Respiratory depression

• Dependence risk

Anxiety Disorders: Complications

Social isolation

SI

IBS

• SNS overactivation = Decreased digestion