Abnormal Psychology Etiologies

Major Depressive Disorder (MDD)

Prevalence Rates

• Prevalence Definition: Statistical concept referring to the number of cases of a disease present in a population at a given time.
• Global Impact: Depression affects over 300 million people worldwide.
• Lifetime Prevalence in the US: Approximately 16.6% of adults may experience MDD.
• Gender Differences: Higher rates in females compared to males; exact reasons unclear, but sociocultural factors may contribute.
• Global Prevalence Challenges: Difficult to determine due to lack of centralized data in many countries; influenced by sociocultural and biological factors.

DSM-IV Criteria for MDD

• Criteria include a depressed mood or loss of interest for over two weeks with impaired social, occupational, or educational function.
• At least five of nine specific symptoms needed for diagnosis, including changes in weight, sleep, activity, energy levels, feelings of guilt, concentration issues, and suicidality.

Biological Etiology

• Neurochemistry: Imbalances in neurotransmitters (serotonin, norepinephrine, dopamine) linked to depression.
• Serotonin: Decrease in production can lead to depression and suicidal mood states.
• Genetic Factors: High heritability, especially in severe depression; 40-50% genetic influence.

Cognitive Approach

• Cognitive Coping Styles: Differences in rumination potentially explain gender disparities in depression rates.
• Nolen-Hoeksema's Theory: Women more prone to rumination, potentially leading to higher depression rates.
• Beck's Cognitive Theory: Depression linked to negative thought patterns (negative triad), schemas, and cognitive biases.

Sociocultural Approach

• Social Factors: Stressful life events, interpersonal relationships, socioeconomic instability linked to depression.
• Brown and Harris Study: Highlights role of social class and life stressors in depression prevalence.

Integration of Approaches

• Understanding depression requires integrating biological, cognitive, and sociocultural factors.
• Research, such as Chiao and Blizinsky, suggests interactions between genetic, cultural dimensions, and depression rates.

Ethical Considerations

• Investigating abnormal behavior must consider ethical implications of attributing depression to genetics, thinking patterns, or sociocultural factors.

Research Methods

• Importance of using varied methods to gain comprehensive understanding of depression's etiology, including clinical interviews and meta-analyses.
• Limitations include potential biases in self-reports and challenges in establishing causation.

Critical Thinking & Methodology

• Methodological considerations in prevalence studies highlight limitations in global data and the role of cultural and economic factors in depression rates.
• The treatment-etiology fallacy and bidirectional ambiguity challenge simple cause-effect assumptions in depression research.

Key Studies & Theories

• Smith et al. (1997) on serotonin depletion.
• Weissman et al. on genetics in depression.
• Farb et al.'s fMRI studies on emotional responses and future depression risk.

Conclusion: Abnormal psychology requires a multifaceted approach, integrating biological, cognitive, and sociocultural factors with ethical and methodological considerations central to understanding and treating disorders like MDD.