1. Models of Abnormal behavior
Naomi Wagner, PhD

2. Categories of Explanations of Abnormal Behavior
Biological: genetics, brain anatomy, biochemical imbalance, central nervous system, etc
Psychological: Emotions, thoughts. Personality, learning
Social: issues with relationships
Sociocultural: norms for behavior, expectations, cultural climate

3. What is a Model? Etiology: Model:
Cause or origin of a disorder
Model:
An analogy used by scientists, usually to describe or explain a phenomenon or process they cannot directly observe
Model, viewpoint, and perspective are often used interchangeably
A multipath model considers interactions among all possible layers of causes

4. Models (cont-d) These one-dimensional views are overly simplistic:
Set up a false “either-or” dichotomy between nature and nurture
Fail to recognize the reciprocal influences of one on the other
Mask the importance of acknowledging the contributions of all four dimensions in the origin of mental disorders

5. The Biopsychosocial Model
Interaction between the possible causes
Multiple pathways to any disorder
Not all causes contribute equally to a disorder
People exposed to the same factors may not develop the same disorder
People exposed to different factors may develop similar disorders

6. The Structure of the nervous System

7. The Structure of the Nervous system
The Central Nervous System: The brain and spinal cord
The Peripheral Nervous System:
A. The Somatic NS
B. The Autonomic NS (sympathetic and para-sympathetic.)

9. Neural Transmission How is information transmitted in the brain
Neurons are separated by a gap (synapse)
The neurons “communicate” at the synapse
Neuron structure: dendrite, cell-body, axon
Electrical signals are transmitted chemically across the synapse
The signals stimulate the “pockets” at the tip of the axon to release neurotransmitter

10. Cont-d Electro- chemical transmission
The signal stimulates the vesicles
Vesicles release the neurotransmitter into the synapse
Neurotransmitter: Chemical substance released from a neuron into the synaptic cleft it drifts across the synapse and is absorbed by the receiving neuron
The signal “floats” on the neurotransmitter to the next neuron
Neurons form inter-connected pathways

11. Cont-d
The neurotransmitters can either excite or inhibit the neuron receiving the signal
The activity of the neuron depends on the balance between “on” and “off” signals
Serotonin is implicated in depression and the OCD.
Dopamine is implicated in schizophrenia (too much) and Parkinson (too little)
GABA (an inhibitory) is implicated in anxiety

12. Biochemical Theories Basic premise: Dendrites: Axons:
Chemical imbalances underlie mental disorders
Dendrites:
Receive signals from other neurons
Axons:
Send signals to other neurons

13. Neural Transmission

14. Selected Neurotransmitters Involved in Some Mental Disorders

15. Abnormalities in Brain Structure
It is not always possible to connect brain structures to psychological symptoms researchers believe that abnormally developed brain structures
In 1848 an explosion during the paving of a rail road caused a metal rod to pierce Phineas Gage eye socket and to enter his brain
As a result he showed significant changes in personality

17. The Human Brain

18. Functions of the brain The forebrain:
Controls all the higher mental functions, such as learning, speech, thought, and memory
Thalamus:
“Relay station;” transmits nerve impulses throughout brain
Hypothalamus:
Regulates bodily drives and body conditions
Limbic system:
Involves experiencing and expressing emotions and motivation

19. Cont-d The midbrain: The hindbrain:
Involved in vision and hearing, and along with the hindbrain, controls sleep, alertness, and pain
Manufactures serotonin, norepinephrine, and dopamine
The hindbrain:
Controls heart rate, sleep, and respiration
Manufactures serotonin

20. Genetic Influences Each cell of our body contains 46 chromosomes
They are made of DNA our genetic material
A gene is a segment of DNA along the length of the chromosome that contain the instructions for forming proteins which in turn determine how the cell works
Proteins are the building blocks of our body

21. Human Chromosomes

22. Genetics (cont-d) Genetic abnormalities can come about through:
Inheritance of particular combinations of genes
Faulty copying when cells reproduce
Mutations that a person acquires over the course of life
Cells possess the ability to repair many of the mutations
The 46 chromosomes are arranged in 23 pairs
One chromosome from mother and one from father

23. Genetics (cont-d)
Genetic makeup plays an important role in developing abnormal conditions
Autonomic nervous system reactivity may be inherited
Hereditary factors are implicated in alcoholism, schizophrenia, and depression

24. What do genes do?
Genes control the manufacturing of neurotransmitters as well as the way the neurotransmitters behave at the synapse
Genes also determine how the brain structures develop throughout life
Any factor that can alter the genetic code can alter how those structures perform

25. Genotype and Phenotype
The 46 chromosomes are arranged in 23 pairs
Twenty-two of the pairs are identical (the 23rd pair is the sex chromosomes XX and XY )
It means that the same gene is located in the same place on each of the chromosomes
Two forms of the same gene are called alleles
The Genotype is the overall genetic makeup
The Phenotype is the expression in your physique and psychological attributes

26. Dominant Recessive Relationship
The Alleles are related to each other in Dominant- Recessive relationship
a dominant allele prevails over a recessive allele
However, human characteristic and psychological disorders are polygenic- more than one gene participates in determining a given characteristic
Epigenetics is the attempt to understand how the environment affects genes to produce genotypes

27. PATTERN OF DOMINANT-RECESSIVE TRAIT INHERITANCE

28. Genes-environment Interactions
Interactions between genes and the environment
Passive exposure: Children are exposed to environments that their parents create based on the parents’ genetic predisposition
The child’s genetically- based traits elicits responses from the environment
Niche-Picking: the child seeks out an environment that gratifies his/her genetically- based inclinations

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

30. Assessment of Genetic Factors
Family inheritance studies: Researchers compare the disorder rates across relatives who have varying degrees of genetic relatedness
Usually comparing Identical twins who share 100% of their genes to Fraternal twins who share 50% of their genes
Studies comparing parents and children are confounded because of possible environmental effect

31. Biologically- Based Therapies
Psychopharmacology:
Study of effect of drugs on mind and behavior
Electroconvulsive therapy:
Application of electric voltage to the brain to induce convulsions
Psychosurgery:
Brain surgery for the purpose of correcting a severe mental disorder