Research Methods in Abnormal Psychology: Structured Study Notes

Ethics and Responsibility in Research

Core Principles of Ethics in Research

Ethical research in psychology is guided by foundational principles to protect participants and ensure integrity.

• Respect for persons: Recognizes the autonomy and dignity of all participants.

• Beneficence: Researchers must secure the well-being of participants, maximizing benefits and minimizing harm.

• Justice: Fairness in the distribution of research benefits and burdens.

The Informed Consent Process

Informed consent is a critical ethical requirement in psychological research.

• Comprehension: Ensure all participants understand the study's nature and procedures.

• Voluntariness: Participation must be voluntary, without coercion.

• Risk and Benefit Assessment: All foreseeable risks and benefits must be considered and communicated.

• Fair Selection: Participants are chosen through a fair and unbiased process.

Research in Abnormal Psychology at the Cellular Level

Neuroanatomy and the Human Nervous System

Understanding the nervous system is essential for research in abnormal psychology.

• Central Nervous System (CNS): Comprises the brain and spinal cord, responsible for processing and transmitting information.

• Peripheral Nervous System (PNS): Includes the somatic nervous system (controls sensation and muscle movement) and the autonomic nervous system (regulates involuntary bodily functions).

The Neuron

Neurons are the fundamental units of the brain and nervous system.

• Soma: The cell body containing the nucleus.

• Dendrites: Branch-like structures that receive signals from other neurons.

• Axon and Axon Terminals: Transmit electrical impulses away from the cell body.

• Synapses: Gaps between neurons where communication occurs via neurotransmitters.

Example:

When a neuron fires, the electrical impulse travels down the axon, triggering the release of neurotransmitters at the synapse.

Parts of the Brain

Brain Stem and Midbrain

The brain stem and midbrain regulate essential life functions and coordinate sensory information.

• Brain Stem: Controls breathing, heartbeat, and motor control (includes medulla, pons, cerebellum).

• Midbrain: Coordinates sensory information and movement.

• Thalamus: Acts as the brain's relay station for sensory input.

• Hypothalamus: Regulates bodily functions and maintains homeostasis.

Forebrain

• Limbic System: Includes the amygdala, cingulate gyrus, and hippocampus; involved in emotions and impulses.

• Basal Ganglia: Inhibits movement and is involved in motor control.

• Cerebral Cortex: Responsible for reasoning, abstract thought, perception of time, and creativity. Divided into two hemispheres, each with four lobes: parietal, temporal, occipital, and frontal.

The Peripheral Nervous System

The peripheral nervous system connects the CNS to limbs and organs.

• Sensory-somatic nervous system: Controls sensation and voluntary muscle movement.

• Autonomic nervous system: Regulates involuntary functions.

  • Sympathetic nervous system: Activates physical readiness (fight or flight).

  • Parasympathetic nervous system: Returns the body to a resting state.

The Endocrine System

The endocrine system uses hormones to regulate bodily functions.

• Hormones: Chemical messengers released by glands directly into the bloodstream.

• Pituitary gland: Known as the "master gland," it controls many endocrine functions.

Neurotransmitters

Neurotransmitters are chemicals that facilitate communication between neurons.

• Electrical and Chemical Communication: Nervous system signals are transmitted both electrically and chemically.

• Release Mechanism: Neurotransmitters are released when an electrical signal reaches the axon terminal.

Example:

Neurotransmitters cross the synapse and bind to receptors on the next neuron, propagating the signal.

Neuroimaging

Neuroimaging techniques allow researchers to visualize brain structure and function.

• CT (CAT) Scan: Uses X-rays to produce images of brain anatomy.

• MRI: Uses radio waves and magnetic fields to create detailed images of the brain.

• Structural Neuroimaging: Examines brain anatomy.

• Functional Neuroimaging: Assesses brain activity by measuring blood flow.

Genetics in Abnormal Psychology

Behavioral Genetics

Behavioral genetics explores the influence of genetics and environment on behavior.

• Family, twin, and adoption studies: Used to distinguish genetic and environmental contributions.

Molecular Genetics

• Genome-wide methods: Examine genetic associations with disorders.

• Epigenetics: Studies heritable changes in gene expression due to environmental exposure.

Genetics Basics

• DNA: The "building block of life."

• Genes: Humans have approximately 20,000 to 25,000 genes organized into 23 pairs of chromosomes.

Adoption Studies

• Compare children with biological and adoptive parents to separate genetic and environmental influences.

Twin Studies

• Compare monozygotic (identical) and dizygotic (fraternal) twins to assess genetic and environmental factors.

• Twins separated at birth provide insight into nonshared environmental effects.

Research in Abnormal Psychology at the Individual Level

Case Studies

Case studies provide comprehensive descriptions of individuals or groups.

• Benefits: Useful for rare phenomena, hypothesis generation, and informing treatment.

• Limitations: Cannot establish causality.

Single-Case Designs

• Experimental studies with individuals serving as their own control.

• Designs such as ABAB (reversal) allow for causal inference.

• Results are not generalizable and may not account for individual differences.

Research in Abnormal Psychology at the Group Level

Correlation Methods

Correlation methods examine relationships between variables.

• Correlation coefficient: Indicates direction and strength, ranging from -1.0 to 1.0.

• Positive correlation: Variables increase together.

• Negative correlation: One variable increases as the other decreases.

• Correlation is not causation.

Controlled Group Designs

• Experimental group: Receives treatment.

• Control group: Serves as comparison.

• Independent variable: Manipulated by researcher.

• Dependent variable: Outcome measured.

• Random assignment: Ensures equal chance of group allocation.

Other Considerations in Randomized Control Trials

• Analogue vs. clinical sample

• Internal vs. external validity

• Effectiveness vs. efficacy research

• Placebo control

• Clinical vs. statistical significance

Improvement of Diversity in Group-Based Research

Diversity in research samples is essential for generalizability.

• Historically, women, older adults, and minorities were underrepresented.

• NIH and other agencies now require inclusion of underrepresented groups in grant-funded research.

Cross-Sectional and Longitudinal Cohorts

Cohort studies track groups sharing common characteristics over time.

• Birth cohort: Individuals born in the same period.

• Inception cohort: Individuals recruited at a common starting point.

• Exposure cohort: Individuals exposed to a specific factor.

• Cross-sectional design: Assesses participants once for a variable.

• Longitudinal design: Assesses participants multiple times over a period.

Research in Abnormal Psychology at the Population Level

Epidemiology

Epidemiology studies disease patterns and influencing factors in populations.

• Prevalence: Total number of cases in a population at a given time.

  • Point prevalence: Cases at a specific point in time.

  • Lifetime prevalence: Cases over a lifetime.

• Incidence: Number of new cases emerging in a given period.

Epidemiological Research Designs

• Observational epidemiology: Documents the presence of disorders.

• Experimental epidemiology: Manipulates exposure to causal or preventive factors.

Table: Types of Research Designs in Abnormal Psychology

Design Type	Main Purpose	Key Features
Case Study	Detailed description of individual/group	Rare phenomena, hypothesis generation
Single-Case Design	Experimental study with one individual	ABAB/reversal, causal inference
Correlation Method	Relationship between variables	Correlation coefficient, no causation
Controlled Group Design	Compare treatment vs. control	Random assignment, independent/dependent variables
Cohort Study	Track group over time	Cross-sectional or longitudinal
Epidemiological Study	Disease patterns in populations	Prevalence, incidence, observational/experimental

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