CAUSES OF ABNORMAL BEHAVIOR:Biological Dimensions

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Abnormal Psychology PSY404

LESSON 11

CAUSES OF ABNORMAL BEHAVIOR

Many questions related to the etiology or causes of abnormal behavior come to one's mind. Such as

What causes depression?

Is it due to biochemical imbalance in the brain?

Is it caused by faulty thinking?

Are there any particular characteristics or lifestyles common among the depressed people?

The cause of abnormal behavior remains a mystery. So let us explore the mystery of the causal factors

underlying abnormal behavior. The major models of studying abnormal behavior or psychopathology

include

Biomedical Model

ii.

Psychoanalytical Model

iii.

Humanistic Model

iv.

Behavioral Model

Cognitive Model

A model is a general orientation to the field of abnormal psychology. Every model has its own assumptions

about human behavior and its own set of hypothesis, how a mental disorder develops and each model

prescribes its own set of treatment.

The major models have their own individual interpretation of the etiological factors of abnormality.

No single model can explain behavior in a satisfactory manner. Therefore, psychologists today focus on

eclecticism, or they use the integrated approach in talking about etiology of a mental disorder.

Multidimensional Integrative Approach

Let us take an example of a sixteen year old girl who suffered from blood-injury-injection phobia.

We would like to study the issue of causation.

In this case, there are biological dimensions, there are psychological dimensions, Emotional, social and

interpersonal influences as well.

---So let us see this example: A young sixteen year old girl was referred for anxiety disorder, after repeated

episodes of fainting. In her biology class the teacher showed a film of dissection of frog, about half way in

the film she felt lightheaded and left the class. Then she began to avoid looking at injured people, visiting

sick at hospital, she could not stand the sight of raw meat or band aids used in covering wounds.--

Biological Dimensions

The biological dimensions include causal factors from the field of genetics and neuroscience that is the girl

has a genetic predisposition to be phobic. So there is a biological dysfunction to be afraid of blood injury

injection. Psychological dimensions include causal factors from behavioral and cognitive processes,

including learning from environment, social learning and even un-conscious processes. The behavioral

responses will include tendency to escape and avoid situations where there would be blood or injury or

injection (hospitals or any road side accident). Emotional influences include increased fear and anxiety,

where as interpersonal influences which includes friends and family would always rush to help the victim

whenever she faints at the sight of blood. Finally, developmental influences would include that a young

sixteen old girl is passing through a difficult stage of development, she is in her teenage years where any

unfortunate phobic reaction may make her more ill at a later stage. n this example we have gone through the

biological influences, the behavioral influences, the emotional influences, social influence and

developmental influences. So we have adopted a multidimensional integrative approach to study blood

injury infection phobia.

Abnormal Psychology PSY404

Influences

Reactions

Biological factors include genes and neuroscience. Increased

Biological

heartbeat, pulse rate, breathing, etc.

Behavioral

Avoidance to see blood or injury or injection, fainting spell.

Emotional / Cognitive

Increased fear and anxiety

Disruptions at school and home, friends and family run to help her,

Social

doctors say nothing is physically wrong.

Developmental

An important developmental stage of sixteen year old teenage girl.

The Bio-Psycho-Social Model studies how biological (evolution, individual genes, brain structure and

chemistry), Psychological (stress, trauma, learned helplessness, mood related perceptions and memories) and

social (roles, expectations, definition of normality and disorder) factors interact to produce specific

psychological disorders. The Multi-Dimensional Integrative Approach and Bio-Psycho-Social Approach are

the same.

Let us take another example:

On 8th October 2005, the northern areas of Pakistan experienced the worst earthquake in the history of the

country. Killing billions making a huge population homeless and without any social support. This traumatic

experience created earthquake phobia in every citizen of the country. You can apply this chart to any one

earthquake victim from your country.

1-Genetic contributions to psychopathology

What causes you to look like one or both of your parents or grand parents? The answer is Genetics or

inheritance.

· Genes are microscopic units of DNA that carry information about heredity. Genes are located on

chromosomes, threadlike microscopic structures found in the nucleus of cells.

· Behavior genetics is a much broader approach that studies genetic influences on the development

of normal and abnormal behavior. A genotype is an individual's actual genetic structure. It is

impossible to observe much of an individual's genotype directly. Instead, what we observe is the

phenotype, the expression of a given genotype. It usually is impossible to infer a precise genotype

from a given phenotype, because phenotypes, but not genotypes, are influenced by the

environment.

· Dominant/recessive inheritance causes some rare forms of mental retardation, but most mental

disorders are not caused by a single gene--Instead, they are polygenic, that is, they are caused by

more than one gene.

· Behavior genetic research is powerful, but unfortunately; people often misinterpret it. One serious

misinterpretation is that a psychological disorder is inevitable, even predestined, if it has a genetic

component. Nature and nurture are not separate influences on behavior. Nature and nurture always

work together.

Huntington a disease of the brain, it is due to genes that cause deterioration in a specific area of the brain

and causes changes in personality, such as cognitive functioning and motor behavior such as un controllable

shaking and jerkiness through out the body.

Another disease due to genetic influence is called Phenyketonuria caused at birth, it is caused by the

inability of the body to break down phenyl-alanine, a chemical compound found in many foods.

In a normal human cell 46 chromosomes are arranged in 23 pairs. In each pair, one chromosome comes

from father and one from mother. The first 22 pairs of chromosomes are programmed for the development

of body and brain and the last pair determines the individual sex. Most of our behavior, personality and

intelligence (IQ) is determined by many genes, each contributing only a tiny portion.

Abnormal Psychology PSY404

Behavior geneticists have developed important methods for studying broad, genetic contributions

to behavior, including family studies, twin studies, and adoption studies.

Family studies ask whether diseases "run in families." where as the Twin studies say that siblings,

DZ twins share an average of 50 percent of their genes, whereas MZ twins share 100 percent of

their genes.

The key comparison involves determining the concordance rate of the two sets of twins;

specifically whether MZ twins are more alike than DZ twins are alike.

A twin pair is concordant when both twins either have the same disorder or are free from the

disorder, for example, both suffer from schizophrenia.

The twin pair is discordant when one twin has the disorder but the other does not, for example,

one twin has schizophrenia but the co-twin does not.

Remember that (1) most emotional problems, like most normal behaviors, appear to be polygenic;

(2) behavior genetic findings fail to specify the mechanism of genetic influence.

2-Gene and Environment interaction

Eric Kendel explored gene and environment interaction and their relationship to psychological disorder. We

will discuss two models 1-the Diathesis-Stress Model and 2-the Reciprocal Gene Environment Model.

Diathesis-Stress Model

In the diathesis-stress model individuals inherit characteristics traits from multiple genes and they have

tendencies to express certain traits and behaviors which may then be activated under conditions of stress i.e.

each inherited tendency is a diathesis which means a condition that makes one vulnerable to developing a

disorder. So when, a stressor comes along the disorder develops. In our example of a sixteen year old girl

suffering form blood injury injection phobia, we can say according to this model that she had vulnerability

or inherited tendency so when she saw the dissection of the frog that acted as a stressor and led to the

expression of disorder. So in this model of gene environment interaction, genetic predisposition was there

and environmental stress provided the opportunity for the disorder to be expressed.

The Reciprocal Gene Environment Model

There is now substantial evidence that people with genetic vulnerability to develop a certain disorder also

have a personality trait for developing a certain disorder such as in case of blood injury injection phobia, the

genetic predisposition, vulnerability and personality traits. All combined in the reciprocal gene environment

model. This model applies to the development of the depression in people.

3-Neuroscience and its contribution to psychopathology

· The field of anatomy is concerned with the study of biological structures, and the field of

physiology investigates biological functions.

· Neuroanatomy and neurophysiology are subspecialties within these broader fields that focus

specifically on brain structures and brain functions.

· The study of neuroanatomy and neurophysiology is the domain of an exciting, multidisciplinary

field of research called neuroscience.

The Neuron

Billions of tiny nerve cells--neurons--form the basic building blocks of the brain.

· Each neuron has four major anatomic components: the soma, or cell body, the dendrites, the axon,

and the axon terminal. The soma--the cell body and largest part of the neuron--is where most of

the neuron's metabolism and maintenance are controlled and performed.

· The dendrites branch out from the soma; they serve the primary function of receiving messages from

other cells.

· The axon is the trunk of the neuron.

· Messages are transmitted down the axon toward other cells with which a given neuron

communicates.

Abnormal Psychology PSY404

The axon terminal is the end of the axon, where messages are sent out to other neurons.

· Within each neuron, information is transmitted as a change in electrical potential that moves from

the dendrites and cell body, along the axon, toward the axon terminal.

· The axon terminal is separated from other cells by a synapse, a small gap filled with fluid.

· Unlike the electrical communication within a neuron, information is transmitted chemically across a

synapse to other neurons. The axon terminal contains vesicles containing chemical substances called

neurotransmitters, which are released into the synapse and are received at the receptors on the

dendrites or soma of another neuron. The process of reuptake, or reabsorption, captures some

neurotransmitters in the synapse and returns the chemical substances to the axon terminal.

· Neuromodulators are chemicals that may be released from neurons or from endocrine glands.

Neuromodulators can influence communication among many neurons by affecting the functioning of

neurotransmitters.

The central nervous system consists of the brain and the spinal cord. The brain uses an average of 140

billion nerve cells called neurons to transmit information throughout the nervous system. A typical neuron

contains a central cell body with two kinds of branches; one kind of branch is called Dendrite having

receptor cells. The other kind of branch called axon that transmits nerve messages to other neuron. So the

brain and neurons are just like a powerful computer and the computer is programmed to control thinking

and actions of each and every organ of the body.

Nerve cells or neurons are not actually connected. There is a small space through which a nerve

impulse or message or nerve current must pass to get to the next neuron. This space between the

axon of one neuron and the Dendrite of another neuron is called the synaptic cleft. The chemical

that is released from the axon of one nerve cell and transmit the impulse to the receptor of another

cell is called the neurotransmitter (Specialized Chemical that defuses across the synaptic gap and

stimulates the next neuron).

Neurotransmitters and Psychopathology Scientists have found that disruptions in the functioning of

various neurotransmitters are present among some people with mental disorders.

· An oversupply of certain neurotransmitters is found in some mental disorders, an undersupply in

other cases, and disturbances in reuptake in other psychological problems.

· Abnormalities in the dopamine system in the brain may be involved in schizophrenia.

· Other evidence links the availability of various neurotransmitters with depression, hyperactivity,

posttraumatic stress disorder, and many other psychological problems.

· The identification of biochemical differences definitely does not mean that these problems are

caused by "a chemical imbalance in the brain," even though many people mistakenly leap to this

conclusion.

The list of neurotransmitters includes Acetylcholine, Nor epinephrine (Noradrenaline) Serotonin,

Dopamine, Glutamate and Gamma Amino Butyric Acid (GABA). Neurotransmitters are chemicals that act

Abnormal Psychology PSY404

on behavior. Increasing or decreasing the flow of neurotransmitters is important. Research on

neurotransmitters tells us that the production of neurotransmitters in different parts of the brain effect

behavior and mood.

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