Lecture Notes: Anxiety and Neurotransmitters

Introduction

Role: Major inhibitory neurotransmitter in the brain.
Conversion: Made from glutamate (an excitatory neurotransmitter) with vitamin B6.
- B6 deficiency or certain medications can hinder GABA production leading to high glutamate and potentially seizures.
Storage: In vesicles within presynaptic neurons.
Receptors:
- GABA-A: Inhibitory, opens chloride channels, hyperpolarizes postsynaptic neurons, used in seizure treatment.
- GABA-B: Linked with muscle relaxation, less clinically significant in psychopharmacology.

Increased GABA activity: Leads to decreased arousal, sedation, and anxiolysis (reduction in anxiety).
Medications Enhancing GABA:
- Benzodiazepines: Common sedative.
- Ethanol and Barbiturates: Enhance GABA activity, used in seizures.
- Muscle relaxants, opioids: Affect GABA-B.

Types: Generalized anxiety, PTSD, OCD, social anxiety, performance anxiety.
Anxiety: Maladaptive response.
- Useful for survival but harmful when chronic or inappropriate.
Neurotransmitters Involved:
- Norepinephrine: High levels during anxiety.
- Serotonin and GABA: Help reduce anxiety.
- Cortisol: Elevated due to anxiety, affects blood sugar, blood pressure, and weight.

Benzodiazepines: Quick relief for acute anxiety, risk of dependence.
- Controlled substances: C4 classification.
- Common Benzos: Alprazolam, Diazepam, Lorazepam, etc.
- Elderly Preference: Lorazepam, Oxazepam, Temazepam (water-soluble, no active metabolites).
Antidepressants: SSRIs, SNRIs for chronic management.
- Common Drugs: Venlafaxine, Duloxetine, Paroxetine, Escitalopram.
- Effectiveness: Takes weeks to see full benefit.
Buspirone: Non-benzodiazepine anxiolytic, good for patients with substance use history.
Beta Blockers: For social and performance anxiety, e.g., Propranolol, Atenolol.

Mechanism: Potentiate GABA by increasing its binding to GABA-A receptors.
Effects: Sedation, memory impairment, risk of respiratory depression with co-ingestion (e.g., alcohol).
Withdrawal: Can cause seizures, requires careful tapering.

Adverse Effects: Drowsiness, sedation, paradoxical excitation (rare), memory impairment.
Tolerance and Dependence: Develops over time; withdrawal can be dangerous.
Antidote: Flumazenil for benzo overdose but caution with chronic users.

Performance Anxiety: Use beta blockers to manage physical symptoms without mental clouding.
Chronic Management: Start with SSRIs/SNRIs, adjust based on response.

Pharmacotherapy should be tailored to individual needs and situations, considering both efficacy and side effects.
Non-pharmacologic therapies should complement medication.

Note: For any questions, reach out to Dr. Wood or attend the next session.