THE BIOLOGICAL MODEL. The biological model focuses on mental disorders as diseases. Mental Disorders are viewed as disorders of the central nervous system, autonomic nervous system and endocrine system.
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THE BIOLOGICAL MODEL
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.
Neurotransmitters and Psychopathology
Malfunctioning of some Neurotransmitters
Norepinephrine Disrupts emergency reaction in acutely
stressful or dangerous situations.
Dopamine Excessive high levels is associated with
Serotonin Disrupts information processing system
and plays an important role in emotional
disorders such as anxiety, depression
GABA Associated with anxiety disorders
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)
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
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
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 &
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
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).
E.) Physical Deprivation:-
Sleep deprivation for 1. disorientation for time and place
72 to 98 hours 2. feeling of depersonalization.
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
Food Deprivation Psychological Impact and problems
Prolonged food 1. Dramatic personality and behavioural
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
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
4. It will be difficult to separate the biological factors from environmental factors totally.