12.5 Causes and Development of Disorders, Epidemiology, and Cultural and Gender Issues in Psychopathology

Causes and Development of Disorders, Epidemiology, and Cultural and Gender Issues in Psychopathology

The Clinical and Abnormal outline lists causes and development of disorders, epidemiology, and cultural or gender issues as distinct subtopics. Questions often ask which model a researcher is using, how to interpret prevalence data, or why a symptom pattern might be misdiagnosed across cultures.

1. Integrative Etiological Models

Diathesis-Stress (Vulnerability-Stress)

A diathesis is a predisposition: genetic liability, neurobiological differences, temperament, or cognitive style. A disorder appears when the diathesis meets enough stress. Paul Meehl (1962) proposed that an inherited neural defect (schizotaxia) becomes schizophrenia only under adverse conditions, and Joseph Zubin and Bonnie Spring (1977) formalized a vulnerability-stress model of episodes. Gene-environment interaction findings such as Caspi's MAOA and 5-HTTLPR studies (Section 1.4) are diathesis-stress examples, and Beck's dysfunctional schemas are cognitive diatheses (Section 12.2).

• Additive versus interactive models: In additive models, diathesis and stress each add risk; in interactive models, stress matters mainly for people with the diathesis.
• Differential susceptibility: Jay Belsky and Michael Pluess proposed that some traits (for example, highly reactive temperament) make individuals more responsive to environments for better and for worse: they fare worst in harsh environments but best in supportive ones.

Biopsychosocial Model

George Engel (1977) argued against a purely biomedical model, proposing that illness reflects interacting biological (genes, neurochemistry), psychological (cognition, emotion, coping), and social (family, poverty, culture) factors. It is the default framework for clinical case conceptualization and for health psychology (Section 13.4).

Developmental Psychopathology

Dante Cicchetti, Alan Sroufe, and Michael Rutter treated disorders as outcomes of developmental pathways rather than fixed diseases:

• Equifinality: Different starting points can lead to the same outcome (depression can arise from genetic risk, early loss, or chronic stress).
• Multifinality: The same risk factor can lead to different outcomes (child maltreatment is linked to depression, PTSD, substance use, or resilience).
• Resilience: Many children exposed to severe adversity develop well. Ann Masten called resilience "ordinary magic," arising from common protective factors such as a supportive adult, cognitive ability, self-regulation, and effective schools. Emmy Werner's Kauai longitudinal study found that about one-third of high-risk children grew into competent adults.
• Cumulative risk: Risk rises with the number of adversities more than with any single one, as in the Adverse Childhood Experiences (ACE) studies, where higher ACE scores predict poorer adult physical and mental health.

Dimensional and Transdiagnostic Frameworks

• Research Domain Criteria (RDoC): Launched by the U.S. National Institute of Mental Health around 2009–2010, RDoC organizes research by functional domains (such as negative valence systems or cognitive systems) measured across units of analysis from genes to behavior, rather than by DSM categories.
• HiTOP: The Hierarchical Taxonomy of Psychopathology (Roman Kotov and colleagues, 2017) models psychopathology as dimensional spectra (internalizing, externalizing, thought disorder, detachment, somatoform) rather than discrete categories.
• The p factor: Avshalom Caspi and colleagues (2014) found that a single general psychopathology factor captures shared liability across many disorders, much as g captures shared variance in mental tests.
• Comorbidity: Co-occurrence of disorders is the rule rather than the exception, one motivation for dimensional models.

Classic Theoretical Perspectives on Causation

Social causation versus social selection (drift): Schizophrenia is more common in lower socioeconomic classes. The social causation hypothesis says poverty's stress contributes to the disorder; the social selection (downward drift) hypothesis says the disorder causes people to drift down the socioeconomic ladder. Evidence supports drift for schizophrenia and a larger role of social causation for depression and substance use.

2. Epidemiology

Epidemiology studies the distribution and determinants of disorders in populations.

Prevalence depends on both incidence and duration: a chronic disorder with few new cases can still have high prevalence.

Benchmark Findings: The National Comorbidity Survey Replication (NCS-R)

Ronald Kessler and colleagues (2005) interviewed a nationally representative U.S. sample using DSM-IV criteria:

• Lifetime prevalence of any disorder: about 46%.
• Lifetime prevalence by class: anxiety disorders about 29%, impulse-control disorders about 25%, mood disorders about 21%, and substance use disorders about 15%.
• 12-month prevalence of any disorder: about 26%.
• Age of onset: half of all lifetime cases begin by about age 14 and three-quarters by about age 24. Median onset is earliest for anxiety and impulse-control disorders (about age 11), later for substance use (about 20) and mood disorders (about 30).
• Treatment gaps: Many people wait years, sometimes decades, between onset and first treatment contact.

Lifetime prevalence of schizophrenia is commonly estimated at about 0.3–0.7%, and of bipolar I disorder at about 1%.

3. Gender and Psychopathology

Explanations combine biology (hormonal changes at puberty, sex-linked genetic factors), psychology (rumination, Section 12.2), and social context (higher exposure to sexual violence, gender-role expectations, help-seeking differences). Diagnostic bias is also possible: women may be overdiagnosed with depression and men underdiagnosed, and identical case descriptions can receive different diagnoses depending on the patient's gender.

Gender roles and expression: The gender gap in depression is partly mirrored by men's higher rates of externalizing problems and substance use, which some theorists interpret as different expressions of distress. Cross-cultural studies show the depression gap in most countries, though its size varies.

4. Culture and Psychopathology

• Universality and variation: Core syndromes such as schizophrenia, depression, and anxiety appear worldwide, but symptom expression, help-seeking, course, and outcome vary. The WHO's international studies of schizophrenia reported better average course in some lower-income countries, although methodological questions remain.
• Somatization: In many cultures, distress is commonly expressed through bodily complaints (fatigue, headaches, dizziness) rather than psychological language; neurasthenia (shenjing shuairuo) was historically a common diagnosis in China.
• Cultural concepts of distress: DSM-5-TR replaced the older term "culture-bound syndromes" with cultural concepts of distress, which include cultural syndromes, idioms of distress, and explanatory models. Examples include ataque de nervios (Latin American; episodes of shouting, crying, trembling, and loss of control after a family stressor), taijin kyofusho (Japanese; fear of offending others through one's appearance, gaze, or odor), khyâl cap ("wind attacks" in Cambodian communities), kufungisisa ("thinking too much" in Zimbabwe), and susto (fright-related soul loss in Latin America).
• Cultural Formulation Interview (CFI): DSM-5-TR includes a 16-question semi-structured interview that asks about the patient's cultural definition of the problem, perceived causes, stressors and supports, cultural identity, and expectations of help, reducing the risk of misinterpreting culturally normative beliefs (such as spiritual experiences) as psychotic symptoms.
• Diagnostic disparities: In the United States, Black patients with mood disorders have historically been more likely than White patients to be diagnosed with schizophrenia, a pattern attributed partly to clinician bias and misreading of culturally shaped symptom presentations.
• Stigma: Public stigma (stereotypes and discrimination) and self-stigma (internalized shame) reduce help-seeking. Contact with people who have mental illness reduces stigma more than education alone, consistent with Allport's contact hypothesis (Section 8.3).
• Thomas Szasz and labeling theory: Szasz (The Myth of Mental Illness, 1961) argued that mental illness is a social label for problems in living, and David Rosenhan's 1973 report "On Being Sane in Insane Places" claimed that pseudopatients were readily admitted and kept on wards. Rosenhan's study is now widely questioned, as later archival investigation found serious discrepancies in his records.