Anxiety


Definition of Anxiety

  • Anxiety: A feeling of unease, such as worry or fear, ranging from mild to severe.

  • Normal and adaptive in some cases (e.g., to prepare for a challenge).

  • Becomes a mental health issue when it disrupts daily activities (e.g., avoidance or isolation).

Symptoms and Causes

  • Symptoms:

    • Emotional: Fear, worry, nervous, uneasy.

    • Physical: Tachycardia, shortness of breath, excessive sweating, trembling or shaking, headache and Dizziness, pins and needles, gastrointestinal disturbances, nausea, fatigue, insomnia.

  • Causes of anxiety symptoms:

    • Biological:

      • Genetics (e.g., panic disorder linked to genetic factors) - not based on a single gene rather a complex genetic basis.

      • Hormonal imbalances (e.g., excessive cortisol release).

    • Past experiences:

      • Difficult experiences in childhood or adolescence

    • Everyday life and habits.

    • Diet:

      • Some types of food can trigger anxiety e.g. sugar, caffeine

    • Physical and mental health:

      • Physical Chronic conditions or mental health conditions e.g. depression

    • Alcohol:

      • It’s a central nervous system depressant which increases GABAergic neurotransmission and can block glutamatergic neurotransmission

      • Disrupts the balance between GABA and glutamate which affects the brain function. Which leads the brain to lower GABA levels and increase glutamate levels triggering anxiety.

    • Drugs:

      • Recreational drugs of abuse can trigger anxiety symptoms via mechanisms unique to a drug or class of drug.

DSM-5 classification of Anxiety Disorders

  • Types of Anxiety Disorders

    • Generalized Anxiety Disorder (GAD):

      • Persistent, excessive worry for ≥6 months.

      • Difficulty controlling worry

      • Anxiety and worry associated with 3 or more of these Symptoms and persistentfor more days than not for 6 months:

        • Restlessness.

        • Fatigue.

        • Difficulty concentrating.

        • Muscle tension.

        • Irritability.

        • Sleep disturbances.

      • Must impair daily living and not be attributable to substances or other conditions.

      • The disturbance is not associated to use of substances

      • The disturbance is not better explained by another medical condition

    • Specific Phobias:

      • Intense fear triggered by a specific object or situation often leads to avoidancebehaviour.

      • Persistent for ≥6 months, impairing daily living.

      • Out of proportion to actual threat.

      • Not associated with substance use or other medical conditions.

    • Social Anxiety Disorder:

      • Intense fear of social situations, leading to avoidance or distress.

      • Symptoms persist ≥6 months, impairing activities of daily life.

      • Not association with substance use or medical-conditions.

    • Panic Disorder:

      • Recurrent panic attacks without clear cause or trigger.

      • Panic attack symptoms (DSM-5 criteria, ≥4 of 13 symptoms):

        • Heart rate increase.

        • Sweating.

        • Trembling.

        • Shortness of breath.

        • Fear of dying.

      • Cycle: Fear of panic attacks → More anxiety → Additional attacks.

    • Substance/Medication-Induced Anxiety Disorder:

      • Anxiety caused by drugs or medications.

    • Anxiety Disorder Due to Medical Condition:

      • Triggered by physiological effects of a medical illness.

  • Post-Traumatic Stress Disorder (PTSD):

    • Triggered by recall of trauma (e.g., violence, serious injury).

    • Symptoms persist ≥1 month, impairing daily activities.

    • Can involve flashbacks, avoidance, and hypervigilance.

  • Obsessive compulsive disorders.

    • OCD is characterised by compulsive, ritualistic behaviour driven by irrational anxiety.

    • Obsession- Recurrent, intrusive thoughts, images, ideas or impulses.

    • Compulsion- repetitive behaviour or mental acts that are performed to reduce anxiety associated with Obsession.

    • Both obsession and compulsion are time consuming and so impairing activities of daily living.

    • Not associated with substance or medical-conditions or better explained by another type of anxiety disorder.

Pathophysiology

  • Stress Response in Anxiety:

    • Inappropriate stress response when no immediate threat exists.

    • Hallmark feature: Dysfunction in the hypothalamic-pituitary-adrenal (HPA) axis.

  • Brain Structures:

    1. Amygdala:

      • Controls fear and emotional response.

      • Hyperactivity linked to anxiety.

      • Stimulates HPA axis to promote cortisol release.

    2. Hippocampus:

      • Role in memory and learning.

      • Suppresses HPA axis to regulate cortisol.

      • Underactivity linked to anxiety, particularly PTSD.

  • Chronic Stress:

    • Prolonged cortisol exposure → Neuronal degeneration (e.g., hippocampal shrinkage).

    • Vicious cycle: Stress → Cortisol → Neuronal damage → More stress response.

Important Considerations

  • Differential Diagnosis:

    • Symptoms should not be better explained by other mental health disorders or substance use.

    • Diagnosis often based on DSM-5 criteria.

Examples of DSM-5 Symptom Differentiation

  • GAD: Worry, restlessness, fatigue, difficulty concentrating.

  • Panic Disorder: Sudden intense fear, physical symptoms (e.g., palpitations, sweating).

  • PTSD: Flashbacks, avoidance, hypervigilance.

Associated Research

  • Hippocampal Volume:

    • MRI studies show reduced hippocampal size in PTSD (Logue et al., 2018).

  • Genetic Links:

    • Research identifies specific genetic components linked to panic disorders (Na et al., 2011).

Key Takeaways

  • Anxiety disorders are highly varied in presentation and severity.

  • The HPA axis and brain structures play crucial roles in anxiety pathophysiology.

  • Effective management involves recognizing the specific disorder, understanding its causes, and addressing both psychological and physiological components.