THE BIOLOGICAL MODEL

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THE BIOLOGICAL MODEL
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1. The biological model focuses on mental disorders
   as diseases.
2. Mental Disorders are viewed as disorders of the
   central nervous system, autonomic nervous system
   and endocrine system.
3. Neither Psychological factors nor a persons
   psychosocial environment is believed to play a
   casual role in the mental disorder.
4. At one time, people belonging to this model hoped
   to find simple biological explanations of mental
   disorders but today it is believed that such
   simple explanations are unlikely to be so simple.
5. Therefore less extreme version of biological
   viewpoint has emerged and known as
   biopsychological viewpoint, which allows other
   casual factors role to be studied in abnormal
   beh, but primarily focuses on the genetic,
   biochemical and

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• other biological processes which become
  imbalanced (for whatever reason) and are
  disrupting normal beh.
• 6. There are mainly five categories of biological
  factors which seem to be relevant to the
  development of maladaptive behaviour
  
  A.) Neurotransmitter and
  harmonal imbalances in the brain. B.) Genetic
  Vulnerability.
  C.) Constitutional
  liabilities.
  D.) Brain dysfunction and
  plasticity.
  E.) Physical deprivation.
• A.) Neurotransmitter and Hormonal Imbalances
• If the brain has to work adequately neurons or
  excited nerve cells should be able to communicate
  effectively with one another.
• The site of communication from one neuron to
  dendrites and to another neuron is the synapse
  (synaptic cleft) a tiny filled space b\w
  neurons.

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• The inter neuronal transmission are accomplished
  by chemicals called neurotransmitters.
• There are many different kinds of
  neurotransmitters, some increase the likelihood
  to produce impulse, while others inhibit impulse.
• While the neural message has been successfully
  transmitted to the post synaptic neuron depends
  on many things such as concentration of certain
  neurotransmitters within the synaptic cleft.
• Imbalances in neurotransmitters can result in
  abnormal behaviour. These imbalances can be due
  to physiological reasons or psychological stress.
• Different Ways Of Creating Imbalances
• Excessive Production and Release of
  Neurotransmitter substance into the synapse cause
  a functional excess in the levels of
  neurotransmitter.
• Dysfunction in the normal process of
  neurotransmitter.

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Once the neurotransmitters are released in the
synapse, they are deactivated. The deactivation
occurs in two ways a.) Once the
neurotransmitter substance is released into the
synaptic cleft, it is deactivated by enzymes
present in the synapse such as monoamine oxidase.
b.)
Sometime neurotransmitters are reabsorbed or
sucked back into the presynaptic axon button,
this process is called reuptake. 3. Dysfunction
can create neurotransmitter imbalances either
when the deactivation enzymes present in synapse
are deficient or there is a slowing of the
ordinary process of reuptake. 4. There may be
problems with the receptors of the post synaptic
neuron they can either be abnormally sensitive or
abnormally insensitive. 5. Different disorders
are thought to stem from the above mentioned
imbalance.
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Neurotransmitters and Psychopathology Malfunctioni
ng of some Neurotransmitters Neurotransmitters
Resulting Problems
Norepinephrine Disrupts emergency reaction
in acutely
stressful or dangerous situations. Dopamine
Excessive high levels is associated
with
schizophrenia. Serotonin Disrupts
information processing system
and plays an important role in
emotional
disorders such as anxiety, depression
and suicide. GABA
Associated with anxiety disorders

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Hormonal Imbalances Hormones are chemical
messengers secreted by a set of endocrine glands
in our bodies. Each of the endocrine glands
produce and release its own set of hormones which
travel through our blood stream and affects parts
of our brain and body. Our central nervous
system is linked to the endocrine system by the
effects of the hypothalamus on the pituitary
gland which is the master gland of the body which
produces a variety of hormones that regulate or
control the other endocrine glands. One important
set of interactions occur in the
hypothalamic-pituitary-adrenal-cortical axis
(hypothalamus receives messages from the central
nervous system and dispatches it to pituitary
which then stimulates the cortical part of the
adrenal gland to produce epinephrine (adrenaline)
and the stress hormone cortisole)
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• Any kind of malfunctioning of this system gives
  rise to various forms of psychopathology.
• Gonadal gland produce sex problems (androgen and
  testosterone in males and estrogens and
  progesterone in females )imbalances in which
  causes maladaptive behaviour. For example - a
  girl who was exposed prenatal to high levels of
  male hormones are likely to show higher levels of
  tomboyism and a preference for toys usually
  preferred by boys. (Berenbaum Itines, 1992)
• B.) Genetic Vulnerabilities
• The biochemical processes are themselves
  effected by genes.
• Although beh is never determined exclusively by
  genes substantial evidence show that some mental
  disorders have a hereditary component.

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• Studies have suggested that heredity is an
  important predisposing causal factor for a number
  of different disorders, such as depression,
  schizophrenia and alcoholism (Plomin et al.,
  1997).
• Genetic Vulnerability does not manifest itself
  until later in life i.e.,- adolescence or
  adulthood.
• In the field of abnormal Psychology genetic
  influence rarely express themselves in a simple
  and straight forward manner. This is because
  behaviour unlike some physical characteristics
  such as eye colour, is not determined exclusively
  by genetic endowment. It is a product of the
  organisms interaction with the environment.
• The subtle influences are transmitted in the
  genetic code itself but if the genes are faulty
  or different from normal, they are believed to
  affect adversely the delicate regulation of brain
  biochemistry and the result will be maladaptive
  behaviour.

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• FAULTY GENES
  PSYCHOPATHOLOGY
• PKU Phenylketonuria Excess amount of
  phenylalanine (a
• chemical
  compound in food) and
• and
  failure of metabolism of this
• substance
  leads to mental
• 
  retardation and seizures.
• 2. Lesch Nyhan Syndr- Lethal neurological
  condition, only
• -ome ( due to recessive males are affected,
  shows bizarre
• gene) behaviour.
• 3. Tay Sachs Disorder Blindness, too much
  blinking,
• (due to recessive movements are
  affected.
• genes)

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• 4. Huntingtons chorea Due to dominant genes-
  results in
• mental
  retardation, emotional distur-
• -bance
  and motor defects.
• b.) Chromosomal Abnormalities-
• The chain like structures with in a cell nucleus
  that contains genes are called chromosomes.
• Advances in research have enabled us to readily
  detect chromosomal abnormalities- irregularities
  in the chromosomal structure- even before birth.
• Normal human cells have 46 chromosomes
  containing the genetic material in which heredity
  plan is encoded.
• When fertilization takes place, the normal
  inheritance consists of 23 pairs of chromosomes,
  one of each pair from

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• the and one from the father.
• Twenty two of these pairs are called autosomes,
  they determine by their biochemical action, the
  general anatomical and physiological
  characteristics. The remaining pair, the sex
  chromosomes, determine an individuals sex. In
  female, both the chromosomes are X and in male,
  from mother it is X and from father it is Y
  chromosome.
• Research development has shown that
  abnormalities in the structure or number of
  chromosomes are associated with wide range of
  malformation and disorders.
• CHROMOSOMAL ABNORMALITIES

• Trisomy 13 An extra chromosome
  in the 13th pair
• causes a
  fatal condition with major
• brain
  abnormalities.

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2. Trisomy 18 An extra
chromosome in the 18th pair
cause fatal condition related to
severe
heart malformation. 3. Trisomy 21
An extra chromosome in the 21th pair
causes down syndrome
and results in
mental retardation , slanted eyes and
flattened
face. 4. Trisomy 23 An extra
chromosome in male causes
klinefelter syndrome resulting in
under
developed testicles and lack of
body hair and 20 of them
are
retarded.
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• 5. Monosomy 23 A lack of X
  chromosome in female
• causes
  turner syndrome resulting in
• short
  stature, webbed necks and
• under
  developed ovaries.
• C.) Constitutional Liabilities
• I. Physical Defects-
• Embroyologic abnormalities or environmental
  conditions operating before or after birth may
  result in physical defects.
• Causes Of Physical Defects-
• Low birth weight
• Nutritional deficiencies

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• 3. Disease
• 4. Exposure to radiation
• 5. Drugs
• 6. Severe emotional stress
• 7. Mothers excessive use of alcohol or tobacco
• These can lead to -
• Learning disorders
• Behavioural disturbances
• Emotional disturbances

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• II. TEMPERAMENT
• It includes reactivity and self regulation. We
  differ in temperament because everybody has
  different ways of reacting to a particular
  stimuli. Temperament is regarded as
  constitutional rather than genetic because it is
  probably due to more than genetic influences
  alone prenatal and postnatal environmental
  factors also play a major role in its
  development. Different temperaments can be
  affected by
• Emotional and arousal responses to various
  stimuli
• Tendency to approach, withdrew and attend to
  various situations

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• Temperament Likelihood of
  developing disorders or
• developed upto 2 to 3 personality
  characteristics
• months
• Fearfulness and Neuroticism the
  disposition to
• irritability experience
  negative effect.
• 2. Positive affect and extra version and
  emotionally positive
• activity level (Watson et
  al.,1994)
• 3. Attentional constraint and
  control behaviour and
• persistence show agree able
  ness.
• 4. Fearfulness behaviourally
  inhibited (Kagan 1993,
• Matheny
  1989) Risk is for developing
• anxiety
  disorders later on in life.

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5. Not at all fearful Highly uninhibited
behaviour,difficulty
in learning moral values from parents
and society.
(Rothbart Ahadi 1994)
Exhibit aggressive delinquent
behaviour
(Schwartz et al, 1996) 6. No fearfulness
Conduct disorder and antisocial and hostility
personality disorder (Harpur,
Hart
Hare 1993) D.) Brain Dysfunction and neural
plasticity- Advances in our understanding of how
the brain functions and how brain dysfunctions
and neural plasticity can lead to psychopathology
have been increased at the rapid pace in the
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• past decade with the increased availability of
  sophisticated new neuro imaging techniques to
  study the function and structure of brain.
• These and other
  kinds of techniques to study brain structure and
  function have been showing that genetic programs
  for brain development are not as rigid and
  deterministic as once believed (Nelson and Blum
  1977)
• Important Observations-
• Significant damage to brain tissues places a
  person at risk for psychopathology.
• The incidence of such damage increases notably
  among the elderly because of aging process
  itself, often resulting in Alzheimers disease
  and cardiovascular insufficiency.
• Brain damage sometimes leads to abnormal beh and
  also increases vulnerability by making a person
  less able to cope.

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4. Genetic programs for brain development are not
as rigid and deterministic for example- Pregnant
monkeys have infants who are jittery and
show exposed to neuro
chemical abnormalities and unpredictable loud
increased level of dopamine and sounds
nor epinephrine (
Schneider,1992) 5. Many environmental events
that occur postnatally also affect the brain
development of the infant and child for
example-the formation of new neural connection
or synapse afterbirth is dramatically affected by
the experience a young organism has. (Greenough
and Black 1992).
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• ENVIRONMENT
  AFFECT
• Rats reared in show heavier and
  thicker cell
• enriched environment development in certain
  portions of the
• cortex
  (more synapse per neuron).
• 2.Reared in social show neuro anatomic
  abnormalities
• isolation from birth in brain regions that
  lead to emotional
• and
  cognitive malfunction and variety
• of
  behavioural and emotional
• 
  abnormalities (Ginsberg et al.,1993).

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E.) Physical Deprivation- Sleep Deprivation
Psychological Problems Sleep
deprivation for 1. disorientation for time
and place 72 to 98 hours 2. feeling
of depersonalization. Mild Sleep Deprivation
Adverse Emotional Consequences Sleep
deprivation leads 1. performance decreased to
excessive sleepiness 2. performance lapses
3. vulnerability
to accidents
4. use of caffeine and alcohol
5. mood and behavioural
problem
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Food Deprivation Psychological
Impact and problems Prolonged food
1. Dramatic personality and behavioural Deprivatio
n changes.
2. Irritable, unsociable,
unable to
concentrate on or day dream about
food only, lying and
stealing food.
3. After six months the predominant
mood was of
gloom and depression
accompanied by apathy, feeling of

inadequacy and loss of interest in
sex.
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Severe malnutrition 1. Impairs physical
development. Associated with 2. Lower
resistance to disease. Prenatal neglect
3. Stunts brain growth markedly Limited access
to lowered intelligence . Health
care 4. Risk for disorders such
as
attention deficit disorder.
5. Attentional problems.
6. Increased
distractibility and
interference with school
performance.
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• STIMULATION AND ACTIVITY-
• Healthy mental development depends on a childs
  receiving adequate amount of stimulation from the
  environment.
• Physical development of the brain is adversely
  affected by an unstimulating environment.
• Enhanced biological development depends on
  enriched and complex environment where the child
  is engaged in different activities in early
  stages of development.
• On the other hand, there are limits to how much
  stimulation is beneficial to a developing
  organism.
• Though we dont have much evidence, but sensory
  overload can impair functioning. As we all know
  that under excessive pressure we may strive to
  decrease the level of stimulation. On the other
  hand under some conditions such as boredom-we may
  strive to increase the level of stimulation by
  doing something.

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• 6. So it is important to have an optimal level of
  stimulation and activity for normal psychological
  functioning.
• IMPACTOF BIOLOGICAL MODEL
• Merits-
• This model has affected the way we think about
  human behaviour.
• We now recognize the important role of bio
  chemical factors and innate characteristics and
  their effect on normal and abnormal behaviour.
• Due to this model, we have witnessed many new
  development in the use of drugs, that can
  dramatically alter the severity and course of
  certain mental disorders, particularly the more
  severe ones like schizophrenia.
• The host of new drugs brought a great deal of
  attention to

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• the biological model, not only in scientific
  circle but also in the popular media.
• 5. Biological treatments based on this model have
  immediate results and they have provided the hope
  that in most cases, biological therapies will
  lead to cure all- immediate results with
  seemingly little effort.
• Demerits-
• It will be a mistake to emphasize this model
  only. It will be useful if used with other models
  and there are several common errors in a way
  people interpret the biological advances.
• No direct link between biological causes and
  mental disorders are found, the relationship is
  complex.
• If we find biological base for any disorder, we
  say that the person is ill but in this way our
  personality traits have also biological base,
  then are they reflect our illness.

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4. It will be difficult to separate the
biological factors from environmental factors
totally. THANK YOU