etiologies

Multiple Etiologies

Psychological disorders are caused by the interaction of various factors, including biological, cognitive, and sociocultural.

Biological Etiology of PTSD

Focuses on brain abnormalities such as reduced hippocampal volume which is linked to PTSD symptoms.

Hippocampus

A brain region implicated in PTSD, often showing reduced volume in individuals with the disorder.

Ventromedial Prefrontal Cortex (vmPFC)

Brain area involved in emotion regulation, whose reduced activity is associated with PTSD.

Amygdala

Brain region associated with fear responses, which can be affected by abnormalities in PTSD.

Cognitive Appraisal

How individuals interpret traumatic experiences, influencing their emotional and psychological responses.

Negative Cognitive Appraisals

Thought patterns that assess trauma and its effects pessimistically, linked to increased PTSD symptoms.

Ehler and Clark's Cognitive Model of PTSD

Proposes that persistent PTSD results from negative appraisals combined with memory disturbances.

Hitchcock et al. (2015) Study

Aim

To explore how survivors’ appraisals of their trauma (e.g., “I’m permanently damaged”) predict PTSD severity over time.

Methods

• Participants: Assault survivors assessed 1 and 6 months post-trauma.
• Measures: Self-report scales of negative appraisals, PTSD symptom checklists, and control for initial symptom levels.

Results

• Stronger negative appraisals at 1 month predicted higher PTSD symptoms at 6 months, even after controlling for initial symptom severity.

Conclusions

How people interpret their trauma—beyond the trauma itself—drives whether acute stress reactions evolve into chronic PTSD.

Top-Down Processing

The brain mechanism where higher cognitive functions (like the vmPFC) regulate emotional responses.

Socioeconomic Status (SES)

A significant sociocultural factor influencing PTSD risk; lower SES is correlated with increased vulnerability.

Irish et al. (2011) Study

Aim (SOC)

To examine how gender and socioeconomic status (SES) jointly influence PTSD prevalence among motor-vehicle accident survivors.

Methods

• Participants: 356 adult survivors of serious car crashes.
• Design: Cross-sectional surveys assessed PTSD symptoms, demographic data (gender, income), and potential mediators (e.g., coping resources).

Results

• Women had about twice the PTSD rates of men.
• Lower-income survivors reported more severe PTSD symptoms.
• When controlling for SES, the gender gap narrowed—suggesting part of women’s higher risk stems from socioeconomic factors.

Conclusions

Both being female and having lower SES independently elevate PTSD risk; SES helps explain, but does not entirely account for, the gender difference.

Garrison et al. (1995) Study

Aim (SOC)

To examine rates and correlates of posttraumatic stress disorder (PTSD) in adolescents exposed to Hurricane Andrew. PubMed

Methods

A random-digit-dial sample of 378 adolescent-parent pairs (158 Hispanic, 116 Black, 104 White) in high- and low-impact zones of Dade County, Florida, completed structured telephone interviews six months post-hurricane. Interviews assessed disaster experiences, emotional reactions, losses, lifetime trauma exposure, recent stressors, and psychiatric symptoms. PubMed

Results

– PTSD prevalence: Only about 1 in 10 girls and 1 in 30 boys met full PTSD.

• Nearly everyone had some stress: shaky nights, jumpy mornings, worries.

• Kids dealing with loss—of home, school, or routine—struggled the most, even more than those who saw the worst of the storm itself.

Conclusions

While a relatively small percentage of adolescents developed full PTSD, most reported some posttraumatic symptoms. The findings highlight that post-disaster planning should address ongoing stressors (e.g., displacement, family upheaval) as key drivers of adolescent distress—often more so than direct disaster exposure.

Correlational Studies

Research methods that examine relationships between variables, often used in PTSD research.

Causation Limitations

Correlational studies cannot establish cause-and-effect relationships.

Gilbertson et al. (2002) Study

Aim(BIO)

To determine whether smaller hippocampal volume is a pre-existing risk factor for PTSD, rather than a consequence of trauma exposure.

Methods

• Participants: Vietnam-era monozygotic twin pairs (one combat-exposed twin, one non-exposed).
• Design: MRI scans measured hippocampal volume in both exposed and unexposed twins; PTSD diagnosis was assessed via clinical interviews.

Results

• Combat-exposed twins with PTSD had significantly smaller hippocampi than exposed twins without PTSD.
• Crucially, their non-exposed co-twins also showed reduced hippocampal volume—despite never having trauma exposure.

Conclusions

Lower hippocampal volume appears to be a vulnerability marker for developing PTSD after trauma, not simply a result of it.

Luby et al. (2013) Study

Aim(SOC)

To assess how childhood poverty and caregiving quality affect hippocampal development and later depression.

Methods

• Participants: Socioeconomically diverse preschoolers followed longitudinally.
• Assessments: MRI hippocampal volumes, observational measures of caregiver support, and later clinical interviews for depression.

Results

• Early caregiver support—but not poverty per se—predicted larger hippocampal volumes.
• Smaller hippocampi at school age were associated with higher depression rates in adolescence.

Conclusions

Supportive caregiving buffers the neurobiological impact of early stress; similar mechanisms may underlie resilience or vulnerability to PTSD after trauma.

Survivor's Guilt

A negative cognitive appraisal where individuals feel guilt for surviving a traumatic event.

Memory Disturbances

Cognitive deficits related to fear conditioning, significant in PTSD symptom maintenance.

Urry et al. (2006) Study

Aim (COG/BIO)

To identify the neural mechanisms by which cognitive reappraisal reduces negative emotional responses.

Methods

• Participants: Healthy adults in an fMRI scanner.
• Procedure: Viewed aversive images under two conditions—“Attend” (just look) vs. “Reappraise” (reinterpret to feel less negative).

Results

• Reappraisal increased activation in prefrontal regions (dlPFC, vlPFC) and reduced amygdala response.
• Stronger PFC–amygdala coupling predicted greater success in down-regulating negative affect.

Conclusions

Top-down cognitive control networks can modulate emotion-generating circuits; deficits in this system may underlie vulnerability to PTSD.

Cultural Beliefs in PTSD

Sociocultural factors like cultural beliefs can influence diagnosis and potential etiology of PTSD.

Research Evaluation

Critical thinking involves identifying research limitations and considering alternative explanations.

IB Psychology Paper 2 Structure

Include theory/etiology introduction, supporting studies, evaluations, and critical thinking.

Vulnerability Marker

Indicates that certain biological characteristics, like reduced hippocampal volume, may increase PTSD risk.