Models of Abnormal behavior Models of Abnormal behavior

Naomi Wagner, PhD Naomi Wagner, PhD

Categories of Explanations of Categories of Explanations of Abnormal Behavior Abnormal Behavior

• Biological: genetics, brain anatomy, Biological: genetics, brain anatomy, biochemical imbalance, central biochemical imbalance, central nervous system, etcnervous system, etc

• Psychological: Emotions, thoughts. Psychological: Emotions, thoughts. Personality, learning Personality, learning

• Social: issues with relationshipsSocial: issues with relationships• Sociocultural: norms for behavior, Sociocultural: norms for behavior,

expectations, cultural climateexpectations, cultural climate

What is a Model?What is a Model?

• Etiology: Etiology: – Cause or origin of a disorderCause or origin of a disorder

• Model: Model: – An analogy used by scientists, usually to describe or explain a phenomenon or process An analogy used by scientists, usually to describe or explain a phenomenon or process

they cannot directly observethey cannot directly observe– Model, viewpoint, and perspective are often used interchangeablyModel, viewpoint, and perspective are often used interchangeably

• A multipath model considers interactions among all possible layers of causes A multipath model considers interactions among all possible layers of causes

• Etiology: Etiology: – Cause or origin of a disorderCause or origin of a disorder

• Model: Model: – An analogy used by scientists, usually to describe or explain a phenomenon or process An analogy used by scientists, usually to describe or explain a phenomenon or process

they cannot directly observethey cannot directly observe– Model, viewpoint, and perspective are often used interchangeablyModel, viewpoint, and perspective are often used interchangeably

•

Models (cont-d) Models (cont-d)

• These one-dimensional views are These one-dimensional views are overly simplistic:overly simplistic:– Set up a false “either-or” dichotomy Set up a false “either-or” dichotomy

between nature and nurture between nature and nurture – Fail to recognize the reciprocal influences Fail to recognize the reciprocal influences

of one on the otherof one on the other– Mask the importance of acknowledging Mask the importance of acknowledging

the contributions of all four dimensions in the contributions of all four dimensions in the origin of mental disordersthe origin of mental disorders

The Biopsychosocial ModelThe Biopsychosocial Model

• Interaction between the possible Interaction between the possible causescauses

• Multiple pathways to any disorderMultiple pathways to any disorder• Not all causes contribute equally to a Not all causes contribute equally to a

disorderdisorder• People exposed to the same factors People exposed to the same factors

may not develop the same disorder may not develop the same disorder • People exposed to different factors People exposed to different factors

may develop similar disordersmay develop similar disorders

The Structure of the nervous System The Structure of the nervous System

The Structure of the Nervous The Structure of the Nervous system system

• The Central Nervous System: The The Central Nervous System: The brain and spinal cordbrain and spinal cord

• The Peripheral Nervous System: The Peripheral Nervous System:

• A. The Somatic NSA. The Somatic NS

• B. The Autonomic NS (sympathetic B. The Autonomic NS (sympathetic and para-sympathetic.)and para-sympathetic.)

Neural Transmission Neural Transmission How is information transmitted in the How is information transmitted in the

brain brain

• Neurons are separated by a gap (synapse)Neurons are separated by a gap (synapse)

• The neurons “communicate” at the The neurons “communicate” at the synapsesynapse

• Neuron structure: dendrite, cell-body, axonNeuron structure: dendrite, cell-body, axon

• Electrical signals are transmitted Electrical signals are transmitted chemically across the synapse chemically across the synapse

• The signals stimulate the “pockets” at the The signals stimulate the “pockets” at the tip of the axon to release neurotransmittertip of the axon to release neurotransmitter

Cont-dCont-d

• Electro- chemical transmissionElectro- chemical transmission• The signal stimulates the vesiclesThe signal stimulates the vesicles• Vesicles release the neurotransmitter into the Vesicles release the neurotransmitter into the

synapsesynapse• NeurotransmitterNeurotransmitter: Chemical substance released : Chemical substance released

from a neuron into the synaptic cleft it drifts from a neuron into the synaptic cleft it drifts across the synapse and is absorbed by the across the synapse and is absorbed by the receiving neuronreceiving neuron

• The signal “floats” on the neurotransmitter to the The signal “floats” on the neurotransmitter to the next neuronnext neuron

• Neurons form inter-connected pathwaysNeurons form inter-connected pathways

Cont-dCont-d

• The neurotransmitters can either excite or The neurotransmitters can either excite or inhibit the neuron receiving the signalinhibit the neuron receiving the signal

• The activity of the neuron depends on the The activity of the neuron depends on the balance between “on” and “off” signalsbalance between “on” and “off” signals

• Serotonin is implicated in depression and Serotonin is implicated in depression and the OCD.the OCD.

• Dopamine is implicated in schizophrenia Dopamine is implicated in schizophrenia (too much) and Parkinson (too little)(too much) and Parkinson (too little)

• GABA (an inhibitory) is implicated in GABA (an inhibitory) is implicated in anxietyanxiety

Biochemical Theories Biochemical Theories

• Basic premise: Basic premise: – Chemical imbalances underlie mental Chemical imbalances underlie mental

disordersdisorders

• Dendrites: Dendrites: – Receive signals from other neuronsReceive signals from other neurons

• Axons: Axons: – Send signals to other neuronsSend signals to other neurons

Neural Transmission Neural Transmission

Selected Neurotransmitters Selected Neurotransmitters Involved in Some Mental Disorders Involved in Some Mental Disorders

Abnormalities in Brain Structure Abnormalities in Brain Structure

• It is not always possible to connect brain It is not always possible to connect brain structures to psychological symptoms structures to psychological symptoms researchers believe that abnormally researchers believe that abnormally developed brain structures developed brain structures

• In 1848 an explosion during the paving of a In 1848 an explosion during the paving of a rail road caused a metal rod to pierce Phineas rail road caused a metal rod to pierce Phineas Gage eye socket and to enter his brain Gage eye socket and to enter his brain

• As a result he showed significant changes in As a result he showed significant changes in personality personality

The Human BrainThe Human Brain

Functions of the brainFunctions of the brain

• The forebrain:The forebrain:– Controls all the higher mental functions, such Controls all the higher mental functions, such

as learning, speech, thought, and memoryas learning, speech, thought, and memory– Thalamus: Thalamus:

•““Relay station;” transmits nerve impulses Relay station;” transmits nerve impulses throughout brainthroughout brain

– Hypothalamus: Hypothalamus: •Regulates bodily drives and body conditionsRegulates bodily drives and body conditions

– Limbic system: Limbic system: • Involves experiencing and expressing emotions Involves experiencing and expressing emotions

and motivationand motivation

Cont-dCont-d

• The midbrain:The midbrain:– Involved in vision and hearing, and along Involved in vision and hearing, and along

with the hindbrain, controls sleep, with the hindbrain, controls sleep, alertness, and painalertness, and pain

– Manufactures serotonin, norepinephrine, Manufactures serotonin, norepinephrine, and dopamineand dopamine

• The hindbrain:The hindbrain:– Controls heart rate, sleep, and respirationControls heart rate, sleep, and respiration– Manufactures serotoninManufactures serotonin

Genetic Influences Genetic Influences

• Each cell of our body contains 46 Each cell of our body contains 46 chromosomes chromosomes

• They are made of DNA our genetic material They are made of DNA our genetic material

• A gene is a segment of DNA along the length A gene is a segment of DNA along the length of the chromosome that contain the of the chromosome that contain the instructions for forming proteins which in turn instructions for forming proteins which in turn determine how the cell works determine how the cell works

• Proteins are the building blocks of our bodyProteins are the building blocks of our body

Human Chromosomes Human Chromosomes

Genetics (cont-d) Genetics (cont-d)

– Genetic abnormalities can come about through:Genetic abnormalities can come about through:• Inheritance of particular combinations of genesInheritance of particular combinations of genes•Faulty copying when cells reproduceFaulty copying when cells reproduce•Mutations that a person acquires over the Mutations that a person acquires over the

course of lifecourse of life•Cells possess the ability to repair many of the Cells possess the ability to repair many of the

mutations mutations •The 46 chromosomes are arranged in 23 pairs The 46 chromosomes are arranged in 23 pairs •One chromosome from mother and one from One chromosome from mother and one from

fatherfather

Genetics (cont-d) Genetics (cont-d)

• Genetic makeup plays an important Genetic makeup plays an important role in developing abnormal role in developing abnormal conditionsconditions

• Autonomic nervous system reactivity Autonomic nervous system reactivity may be inheritedmay be inherited

• Hereditary factors are implicated in Hereditary factors are implicated in alcoholism, schizophrenia, and alcoholism, schizophrenia, and depressiondepression

What do genes do? What do genes do?

• Genes control the manufacturing of Genes control the manufacturing of neurotransmitters as well as the way the neurotransmitters as well as the way the neurotransmitters behave at the synapseneurotransmitters behave at the synapse

• Genes also determine how the brain Genes also determine how the brain structures develop throughout lifestructures develop throughout life

• Any factor that can alter the genetic code Any factor that can alter the genetic code can alter how those structures perform can alter how those structures perform

Genotype and Phenotype Genotype and Phenotype

• The 46 chromosomes are arranged in 23 The 46 chromosomes are arranged in 23 pairs pairs

• Twenty-two of the pairs are identical (the 23Twenty-two of the pairs are identical (the 23rdrd pair is the sex chromosomes XX and XY )pair is the sex chromosomes XX and XY )

• It means that the same gene is located in the It means that the same gene is located in the same place on each of the chromosomessame place on each of the chromosomes

• Two forms of the same gene are called alleles Two forms of the same gene are called alleles • The Genotype is the overall genetic makeupThe Genotype is the overall genetic makeup• The Phenotype is the expression in your The Phenotype is the expression in your

physique and psychological attributesphysique and psychological attributes

Dominant Recessive Dominant Recessive RelationshipRelationship

• The Alleles are related to each other in The Alleles are related to each other in Dominant- Recessive relationship Dominant- Recessive relationship

• a dominant allele prevails over a recessive a dominant allele prevails over a recessive allele allele

• However, human characteristic and However, human characteristic and psychological disorders are polygenic- psychological disorders are polygenic- more than one gene participates in more than one gene participates in determining a given characteristic determining a given characteristic

• Epigenetics is the attempt to understand Epigenetics is the attempt to understand how the environment affects genes to how the environment affects genes to produce genotypesproduce genotypes

PATTERN OF DOMINANT-RECESSIVE TRAIT PATTERN OF DOMINANT-RECESSIVE TRAIT INHERITANCEINHERITANCE

Genes-environment InteractionsGenes-environment Interactions

– Interactions between genes and the Interactions between genes and the environmentenvironment

– Passive exposure: Children are exposed Passive exposure: Children are exposed to environments that their parents to environments that their parents create based on the parents’ genetic create based on the parents’ genetic predisposition predisposition

– The child’s genetically- based traits The child’s genetically- based traits elicits responses from the environment elicits responses from the environment

– Niche-Picking: the child seeks out an Niche-Picking: the child seeks out an environment that gratifies his/her environment that gratifies his/her genetically- based inclinationsgenetically- based inclinations

Diathesis-Stress Model Diathesis-Stress Model

• Proposal that people are born with a Proposal that people are born with a predisposition that places them at predisposition that places them at risk for developing a psychological risk for developing a psychological disorder if exposed to certain disorder if exposed to certain extremely stressful life experiences.extremely stressful life experiences.

Assessment of Genetic Factors Assessment of Genetic Factors

– Family inheritance studies: Family inheritance studies: Researchers Researchers compare the disorder rates across relatives compare the disorder rates across relatives who have varying degrees of genetic who have varying degrees of genetic relatednessrelatedness

– Usually comparing Identical twins who share Usually comparing Identical twins who share 100% of their genes to Fraternal twins who 100% of their genes to Fraternal twins who share 50% of their genes share 50% of their genes

– Studies comparing parents and children are Studies comparing parents and children are confounded because of possible confounded because of possible environmental effect environmental effect

Biologically- Based Therapies Biologically- Based Therapies

• Psychopharmacology: Psychopharmacology: – Study of effect of drugs on mind and Study of effect of drugs on mind and

behaviorbehavior

• Electroconvulsive therapy: Electroconvulsive therapy: – Application of electric voltage to the brain to Application of electric voltage to the brain to

induce convulsionsinduce convulsions

• Psychosurgery: Psychosurgery: – Brain surgery for the purpose of correcting a Brain surgery for the purpose of correcting a

severe mental disordersevere mental disorder