Fear, Stress, and Anxiety Lecture Review

Distinction Between Fear and Anxiety

• Fear: Defined as a response to a specific, perceived source of danger. This threat may be directed toward oneself or a loved one. Fear is characterized by its ability to subside quickly once the threat has been removed.

• Anxiety: Defined by Lazarus (1991) as a more general expectation that something bad might happen. Unlike fear, it is not tied to a specific object or event but is a response to a pervasive, ongoing sense of uncertainty and threat.

• Social Anxiety: A specific form of anxiety limited to interpersonal situations. It is particularly prevalent in scenarios involving meeting new people or situations where the individual is the focus of others' attention.

• Differentiating Factors: If a person is anxious about public spaces, social encounters, or failing to meet internal or external expectations, relaxation is difficult because these situations occur frequently in daily life.

The Biological Concept of Stress

• Definition: Stress is not an emotion itself but is the result of emotion and a cause for various other conditions.

• Hans Selye (1979): Popularized the concept of stress as the "nonspecific response of the body to any demand made upon it."

• General Adaptation Syndrome (GAS): Selye proposed that any threat to the body activates a generalized response, primarily due to the activity of the adrenal glands. This is viewed as a process rather than a momentary reaction.

The Three Stages of Stress (GAS Model)

• 1. Alarm: This is the initial "fight or flight" stage.

  • The adrenal glands release adrenaline (epinephrine).

  • This stimulates the sympathetic nervous system to prepare the body for brief emergency activity.

  • The adrenal glands also release cortisol, which increases blood glucose levels to provide extra energy.

  • The body temporarily suppresses non-essential activities, such as sexual arousal, to conserve energy for the emergency.

• 2. Resistance: The stage where the body attempts to adapt to a prolonged threat.

  • The initial sympathetic response declines.

  • The adrenal glands continue to secrete cortisol and other hormones to maintain prolonged alertness.

  • The body adapts by decreasing extraneous activity to save energy or adapting to physical stressors like heat, cold, or low oxygen.

• 3. Exhaustion: Occurs after intense, prolonged stress.

  • The individual becomes tired, inactive, and vulnerable.

  • The nervous and immune systems no longer have the energy to sustain responses. This is often associated with the concept of "burnout."

Stress in Industrialized Societies

• Prolonged Crises: Robert Sapolsky (1998) argued that modern crises are often prolonged (e.g., working for a domineering boss, paying bills with inadequate income, or caring for chronically ill relatives) compared to the short-term fight-or-flight triggers of the evolutionary past.

• Evolutionary Mismatch: A characteristic that spread because it was beneficial as an adaptation in the past is not necessarily functional in modern environments. Prolonged activation of GAS in industrial societies can lead to widespread stress-related and psychiatric illnesses.

Evolutionary Foundations of Fear

• The Function of Fear: Fear pulls attention toward possible physical harm and aids in avoidance. It is innate regarding certain stimuli:

  • Sudden Loud Noises: Frightens virtually all humans from birth and is present in almost all animal species with hearing.

  • Dark Places: A common human fear.

  • Separation: Particularly built-in for young children regarding loved ones.

• Categories of Fear Stimuli:

  1. Animals (snakes, spiders, dogs).

  2. Social threats (unfamiliar people, unwanted attention).

  3. Physical threats (heights, thunder).

• Predator Fear: Öhman (2009) suggests predators like snakes are primordial targets. Isbell (2006) proposes we inherited this from small mammalian ancestors for whom snakes were primary predators.

• Prepared Learning: A proposal by Öhman, Eriksson, & Olofsson (1975) and Seligman (1971) that humans are biologically predisposed to learn certain fears (like snakes) more easily than others.

Behavioural Measures of Fear: Facial Expressions

• The Prototypical Expression: Identified by Ekman in research on basic emotions.

  • Inner and outer eyebrows are lifted and pulled together.

  • The eyes widen.

  • Muscles below the lip corners contract, pulling the lower cheeks down and to the side.

  • The mouth may open slightly.

  • This pattern closely resembles the expression of surprise.

The Startle Reflex

• Definition: A rapid, automatic defensive response to sudden, intense stimuli (loud noises, bright flashes, or unexpected touch).

• Biological Pathway: Auditory information travels to the cochlea and then to the pons in the brainstem. The pons commands the tensing of muscles, particularly the neck muscles, to protect this vulnerable area.

• Characteristics: It is rapid, involuntary, and protective. It becomes more vigorous if a person is already tense. It is often altered in individuals with PTSD, anxiety disorders, or neurodegenerative conditions.

• Startle Potentiation: Enhancement of the startle response in frightening or unpleasant situations compared to safe ones (Lang, Bradley, & Cuthbert, 2002).

  • Example: A loud noise is more startling when walking through a dangerous neighborhood at night than when at home with friends.

• Fear Conditioning Research: In rats, a tone associated with a shock will subsequently increase the startle response to a loud noise. Conversely, a tone associated with safety or pleasant events will decrease the startle response (Schmid et al., 1995).

Movement Suppression and Eye Movement Measures

• Freezing (Suppression of Movement): A reduction or cessation of voluntary movement in response to threat.

  • Functions: Helps avoid detection and prepares the body for action.

  • Application: Used with rats in unfamiliar enclosures. In humans, it is used to study children with an "inhibited temperament" who remain in the background and avoid exploration (Kagan, Reznick, & Snidman, 1988).

• Attentional Bias (Eye-Tracking): People focus more on emotional images than neutral ones, especially in the first few seconds (Calvo & Avero, 2005).

  • Anxious Individuals: Show an attentional bias towards threat. Eye-tracking shows they perform more backward eye movements when reading threatening sentences, indicating they stop and reread fear-provoking content (Calvo & Avero, 2002).

Anxiety Disorders

• Excessive Anxiety: Anxiety disorders occur when the level of anxiety is disproportionate to the circumstances.

• Panic Disorder: Characterized by frequent anxiety periods and attacks involving rapid breathing, sweating, trembling, and increased heart rate (extreme sympathetic arousal).

  • Fear of Fear: Frequent fear of the next attack can become incapacitating.

  • Demographics: More common in women than men; more common in adolescents and young adults than the elderly.

• Biological and Physical Links:

  • Joint Laxity: Occurs in approximately $15 \%$ of people who are "double-jointed." These individuals tend to have stronger than average fears even without the disorder.

  • Genetics: Twin studies suggest predisposition, but no single gene is identified.

  • Neurology: Linked to the hypothalamus rather than the amygdala. Associated with decreased $GABA$ activity and increased Orexin levels.

• Orexin: A neuropeptide produced in the lateral hypothalamus. It regulates wakefulness, motivation, and stress responses. Blocking orexin receptors can block panic responses (Johnson et al., 2015).

Post-Traumatic Stress Disorder (PTSD)

• Symptoms: Flashbacks, distressing nightmares, avoidance of reminders, and vigorous reactions to noises/stimuli (Yehuda, 2002).

• Neurological Findings:

  • Hippocampus: PTSD victims often have a smaller than average hippocampus. Severe stress can cause the hippocampus to shrink (Kim et al., 2015). However, monozygotic twin studies by Gilbertson et al. (2002) showed that non-combat twins also had smaller hippocampi, suggesting a predisposition rather than just a result of trauma.

  • Amygdala: In a study of war veterans by Koenigs et al. (2008), none of the subjects with amygdala damage suffered from PTSD, whereas $40 \%$ of those with damage elsewhere in the brain did. This suggests the amygdala is essential for the emotional impact that generates PTSD.

Pharmacological Anxiety Relief

• Benzodiazepines: The most common anxiolytics (e.g., Diazepam/Valium, Chlordiazepoxide/Librium, Alprazolam/Xanax).

  • Mechanism: They bind to the $GABA_A$ receptor, twisting it so that $GABA$ (the inhibitory neurotransmitter) binds more easily, facilitating chloride ion ($Cl^{--}$) flow into the neuron to hyperpolarize the cell.

  • Locations: Affect the amygdala, hypothalamus, and midbrain.

  • Environmental Impact: They are chemically stable and pass through waste treatment into water systems, where they alter fish behavior (Brodin et al., 2013).

• Alcohol: Reduces anxiety by promoting $Cl^{--}$ flow through certain $GABA_A$ receptor complexes.

• Ro15-4513: An experimental drug that blocks alcohol's effects on the $GABA$ receptor, including its effects on motor coordination and anxiety.

  • A rat given alcohol and then Ro15-4513 showed significantly improved coordination within $2$ minutes.

  • It was not marketed as a "sobering-up" pill because it might encourage people to drink more or risk driving while still impaired.

Questions & Discussion

• Social Anxiety Assessment: Do you experience social anxiety? Under what circumstances?

• Coping Mechanisms: What strategies do you follow to cope with social anxiety?

• Stress Management: How do these biological understandings of the alarm and resistance stages change your perspective on long-term stress?