(5) THEORETICAL APPROACHES IN EXPLAINING THE ETIOLOGY OF PSYCHOLOGICAL DISORDER

ONE-DIMENSIONAL

looking for a single cause

MULTIDIMENSIONAL

looking for a systemic cause

Genetic Paradigm

almost all behavior is heritable to some degree (i.e., it involves genes)

23; 46

People have __ pairs of chromosomes; _ total

22; 1

__ Autosomes; _Sex Chromosome

XX; XY

_ (females); _ (males)

Gene Expression

switch other genes on and off, the flexibility of genes and how they turn on or off has closed the door on beliefs about the inevitability of the effects of genes, good or bad

Polygenic

meaning several genes, perhaps operating at different times during development, turning themselves on and off as they interact with a person’s environment, is the essence of genetic vulnerability

Heritability

refers to the extent to which variability in a particular behavior (or disorder) in a population can be accounted for by genetic factors

Shared Environment

includes those things that members of a family have in common, such as family income level, child-rearing practices, and parents’ marital status and quality

Nonshared Environment

unique environment factors are those things believed to be distinct among members of a family, such as relationships with friends or specific events unique to a person

Genotype

the total genetic makeup of an individual, consisting of inherited genes, which cannot be observed outwardly

Phenotype

the totality of observable behavioral characteristics

Endophenotypes

genetic mechanisms that ultimately contribute to the underlying problems causing the symptoms and difficulties experienced by people with psychological disorders

Alleles

different forms of the same genes, which are commonly found at the same location, or locus, of a chromosome pair

Genetic Polymorphism

refers to a difference in DNA sequence on a gene that has occurred in a population

Single Nucleotide Polymorphism (SNPs)

refers to differences between people in a single nucleotide (A, T, G, or C) in the sequence of a particular gene

Copy Number Variations (CNVs)

• can be present in a single gene or multiple genes.

• The name refers to an abnormal copy of one or more sections of DNA within the gene(s)

Basic Genetic Epidemiology

statistical analysis of family, twin, and adoption studies; whether the disorder can be inherited and how much is attributable to genetics

Family Studies

examine behavioral patterns or emotional traits in the context of the family

Proband

family member with the trait singled out for the study (possibly having a genetic disorder and who may receive genetic counseling or testing)

Adoption Studies

identify adoptees who have a particular behavioral pattern of psychological disorder and attempt to locate first-degree relatives who were raised in different family settings

Twin Studies

usually conducted on identical twins because they share genetic makeup

Advanced Genetic Epidemiology

studies the factors that influence the disorder

Gene Finding

what gene influences the behavior

Molecular Genetics

biological processes genes affect to produce symptoms of the disorder

Epigenetics

“above or outside the gene” and refers to the chemical “marks,” such as DNA methyl tags or histones, that are attached to and protect the DNA in each gene

Neuroscience Paradigm

psychological disorders are linked to aberrant processes in the brain

Neurotransmitters

are the body’s chemical messengers, acting as a crucial communication system for the nervous system

Neurotransmitters

• They are released by neurons and travel across a tiny gap called a synapse to bind receptors on a neighboring cell (can be another neuron, a muscle cell, or a gland)

• This binding process allows the neurotransmitters to either “excite” or “inhibit” the receiving cell, influencing a vast range of bodily functions and psychological states

Excitatory

these neurotransmitters encourage a receiving cell to fire an action potential (an electrical signal), thereby passing the message along

Inhibitory

these neurotransmitters reduce the likelihood that a receiving cell will fire, effectively acting as a “break” on the nervous system

Modulatory

these neurotransmitters can influence a larger group of neurons at once and over a longer period, “fine-tuning” or adjusting how cells communicate

neurons

The cells in the nervous system are called _____, and the nervous system comprises billions of _____

Synapse

is the small gap between the terminal endings of the sending axon and the cell membrane of the receiving neuron

Reuptake

is a process where some of what remains in the synapse is broken down by the enzymes, and some is taken back into the presynaptic cell

Agonist

effectively increases the activity of the neurotransmitters (Excitatory)

Antagonist

decrease or block neurotransmitter (Inhibitory)

Inverse Agonists

produce effects opposite to those produced by neurotransmitters

Neurotransmitters

are chemicals that allow neurons to send signals across the synapse to other neurons

Glutamate (E)

memory

GABA (I)

calming

Serotonin (I)

mood

Dopamine

pleasure/reward

Epinephrine

fight or flight

Norepinephrine

concentration

Endorphins

euphoria

Acetylcholine (E)

learning

Dopamine

High: Schizophrenia

Low: Parkinson’s

Acetylcholine

Low: Alzheimer’s (Dementia)

Norepinephrine

High: Mania

Low: Depression

GABA

High: Relaxation

Low: Anxiety, OCD

Serotonin

High: Mania

Low: Depression, Anxiety, and Eating Disorders

Epinephrine

High: Stress and Sleeping Disorders

Low: Fatigue

Glutamate

High: Psychosis and Neuron death

Low: Huntington’s

Endorphin

Low: Eating Disorders

Gray Matter

the cortex of the human brain is composed of the neurons that form the thin outer covering of the brain

Cerebral Cortex

provides us with our distinctly human qualities, allowing us to look to the plan, to reason, and to create

Left Hemisphere

responsible for verbal and other cognitive processes

Right Hemisphere

perceiving the world around us and creating images

Lobes of the Brain

frontal, parietal, occipital, temporal

Prefrontal Cortex

• One important area of the cortex

• Located in the very front of the cortex

• Helps to regulate the amygdala and is important in many different disorders

• Area responsible for higher cognitive functions

White Matter

made up of large tracts of myelinated (sheathed) fibers that connect cell bodies in the cortex with those in the spinal cord and in other areas of the brain

Ventricles

• cavities deep within the brain

• Filled with cerebrospinal fluid

Cerebrospinal Fluid

circulates through the brain through these ventricles, which are connected with the spinal cord

Brain Stem

lower and more ancient part of the brain; essential for autonomic functions

Hindbrain

contains the medulla, pons, cerebellum; regulates many autonomic activities

Cerebellum

controls motor coordination abnormalities associated with autism

Thalamus and Hypothalamus

involved in regulating behavior, emotions, and hormones

Limbic System

located around the edge of the center of the brain

Hippocampus

associated with memory

Hypothalamus

regulates metabolism, temperature, perspiration, blood pressure, sleeping, and appetite

Amygdala

is an important area for attention to emotionally salient stimuli

Basal Ganglia

base of the forebrain, related to Parkinson’s

Pruning

a number of synaptic connections begin to be eliminated

Brain Networks

are clusters of brain regions that are connected in that activation in these regions is reliably correlated when people perform certain types of tasks or are at rest

Somatic NS

controls muscles

Autonomic NS

innervates the endocrine glands, the heart, and the smooth muscles that are found in the walls of blood vessels, stomach, intestines, kidneys, and other organs

Sympathetic NS

fight or flight response

Parasympathetic NS

helps to calm down the body

Endocrine System

glands produce hormones that are released into the bloodstream

Pituitary

master gland

Thyroid

controls metabolism and growth

Parathyroid

controls the levels of calcium

Adrenal

metabolism, blood pressure, sex development, stress

Pineal

melatonin

Pancreas

insulin

Testes

testosterone

Ovaries

estrogen, progesterone, testosterone

HPA Axis

• is central to the body’s response to stress figures prominently in many of the disorders

• When people are faced with a threat, the hypothalamus releases corticotropin-releasing factor (CRF), which then communicates with the pituitary gland.

• The pituitary then releases adrenocorticotropic hormone, which travels via the blood to the adrenal glands. The outer layers of the adrenal glands are referred to as the adrenal cortex; this area promotes the release of the hormone cortisol

Cortisol

often referred to as the “stress hormone”

Temperament

refers to a child’s reactivity and characteristic ways of self-regulation

Permissive Hypothesis

when serotonin levels are low, other neurotransmitters are permitted to range more widely, become dysregulated, and contribute to mood irregularities

Corpus Callosum

Communication between the left and right hemispheres

Limbic System

Attention, emotion, fight or flight

Frontal Lobe

Learning, abstracting, reasoning, inhibiting

Hypothalamus

Regulation of metabolism, temperature, and emotions

Temporal Lobe

Discrimination of sounds, verbal, and speech behavior

Reticular Formation

Arousal reaction, information screening

Medulla

Breathing, blood pressure, and other vital functions