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Chapter 2

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Kathy Foxall

Chapter 2- abnormal THE GENERAL NATURE OF THEORIES  From early 20 century, there have been 2 main streams of thought concerning mental disorders o 1. Focus on the biological o 2. Focuses on environmental influence  eg nature vs. nurture  Biological approaches tend to downplay the influence of influence of experience.  The psychological approach emphasizes environmental factors in the development of disorders.  John Locke stated humans are born tabula rasa (a blank slate upon which experience writes all that is meaningful in thought and beh.)  Biological and psychodynamic formulations view dysfunctional beh as the product of forces beyond the individuals control, whereas humanistic and existential approaches lay the responsibility for action and choices squarely on the shoulders of the individual  The perspective taken determines many things- it directs research, guides directs the decision and defines treatment responses  The behavioral perspective leads researcher so seen environmental events to shape specific dysfunctional responses and emphasizes the classification of beh rather than of ppl.  This involves either manipulating the environment or modifying the perceptions ppl have regarding their experiences and themselves  The adoption of a perspective is influenced far less by the weight of evidence than by the prevailing social belief system and by an individual’s disposition to see human beh as determined by factors beyond or within the control of the individual.  The clinging onto a theory is not always a bad thing since it allows that theory to be fully explored  A theory should be abandoned only when there is a better one available Levels of theories  When biological psychological perspectives are applied to specific problems, they may become theories that detail the supposed causal chain leading to their emergence of the dysfunctional beh in question.  In single factor explanations, - once factor is said to cause the disorder: ego genetic defect  It often reflects the lack of current comprehensive knowledge of disorders.  Interactionist explanations, which view beh as the product of the interaction of a variety of factors,  It is important to point out that most single factors models reflect the primary focus of the researcher, theorist, or clinician rather than the belief that there really is a single cause.  Eg a cognitive therapist would emphasize the modification of negative automatic thoughts and core beliefs in the treatment of depression.  Theories may be classified according to their level of explanation. o Some theories try to explain all abnormal beh o Others try to account for all disorders within a particular category eg personality disorders o There are theories that endeavor to reveal the causes of a particular prob such as panic disorder o There are theories that attempt to elucidate the influence of a single factor within a more general theory.  Single factor theories, however, should not be considered valueless simply because they may later be discarded for complex explanation  Scientific theories are judged to be valuable not because they describe the enduring truth about an issue, but rather because they embody three essential features o 1. They integrate most of what is currently known about the phenomena in the simplest way possible. o 2. They make testable predictions about aspects of the phenomena that were not previously thought of. o 3. They make it possible to specify what evidence would deny the theory. Testing theories: the null hypothesis  A theory is replaced not because the evidence is not significant but because another theory better explains it.  Experiments are not set up to prove the worth of a theory but rather to reject (or fail to reject) what is called null hypothesis.  Null hypothesis proposes that the prediction made from the theory is false. THE SEARCH FOR CAUSES  The aim for theories about mental disorders are to: 1. Expand the etiology ( the causes) of the probe beh 2. Identify the factors that maintain the beh 3. Predict the Couse of the disorder 4. Design effective treatment  Some ppl feel uncomfortable attributing causes of beh to factors over which a person has little or no control  It is important to note that factors involved in the etiology of a problem may not be relevant to its maintenance o Eg many young ppl initially behind to drink alcohol, smoke, or do drugs to impress others. To appear mature. o Once entrenched, however, habitual use of alcohol, cigarettes, o drugs is maintained by the direct effects of the substance, the distress induced by withdrawal, and environmental cues such as being at the party with friends who drink, smoke or use drugs  Even in disorders where there is a clear biological cause, environmental manipulations may alleviate or even avoid the development of the most serious symptoms.  Ef phenylketonuria (PKU) is an inborn metabolic defect that cases the body to be unable to metabolize phenylalanine, a substance presence in many foods  Untreated PKU will markedly raise blood level of phenylalanine, in a decrease in various neurotransmitters in the brain, thereby producing severe mental retardation.  An even more pertinent observations derives from a study by Baxter and his colleagues (1992) of patients suffering from obsessive-compulsive disorder  Many different theories have been advanced regarding the etiology of mental disorders.  We limit ourselves here to a description of the most popular, grouped by the primary proposed cause 1. Biological, 2. Psychodynamic, 3. Learning beh or cognitive- behavioral theories), 4. Dysfunctional thoughts or beliefs (cognitive theories), 5. Intrapersonal processes (humanistic or existential theories), 6. Socio-cultural influences.  It is reasonable to assume that theses various influences interact to reduce mental disorder.  Even within each of these models, various cases are seen as primary by one or another theorist o Eg within the biological category, some theories emphasize abnormal brain functioning, whereas others place the site of the problem in the autonomic nervous system, in genetic endowment, or in a dysfunctioning endocrine system.  In fact, all of these systems work in concert and it is well- nigh impossible to distinguish their influence.  Dividing this whole system into its presumed components parts all too often has the effect of convincing some theorists that one or another aspect is causally more important than all other features.  This type of thinking, which may attribute primary causation to biological problems (biological determinism), or to socio-cultural or environmental influences (cultural or environmental determinism), is a form of reductionism, in that the actions of the whole are said to be caused by (that is, reduced to the influence of) one or other of the component parts.  Strict biological determinism all too often leads to the dismal conclusion that psychological or environment interventions will do not good.  When it comes to criminal beh , such arguments appeal to many ppl who wish simply to punish offenders while ignoring the possible social factors related to a higher incidence of crime  Similarly, well intentioned clinicians may assume that disorders that are difficult to treat are completely biological.  Recent studies suggest that cognitive therapy and other psychosocial interventions are effective supplements to antipsychotic medication and are now recommended aspects of routine care.  Frequently, cultural or environmental determinists feel obligated to deny the influence of biological disadvantages.  However, no amount f devoted training, expert guidance, or determination would ever make a person who is 1.5 meters tall into a world-class high jumper.  To understand the various theoretical approaches to abnormal beh, we will have to consider them separately, as that is the way they have always been described. This separation, however, should not be taken to mean that we agree with any one model that assumes the prior causal control of beh. BIOLOGICAL MODELS  Responses like endler’s (see green section on page 26) have encouraged many theorists to look for biological causes of abnormal behavior.  Biological theorists of human beh typically not only borrow their model from medicine, but also co-opt the Lang of medicine, calling clients: patients “and their problems “symptoms” or “syndromes” and describing the response to these problems as treatment. Thus, adopting a biological model has implications for the way in which people with problems are dealt with.  The same is true for all theoretical perspectives, and it is necessary to consider the ramification of these often unnoticed implications when deciding on a particular point of view about abnormal beh  To appreciate the meaning of the various biological explanation of disordered beh or thinking, it is necessary to have some understanding or relevant aspects of bodily functioning.  Biological theories have primarily implicated dysfunctions in or damage to the brain ( the central nervous system, or CNS), problems of control of one or another aspects of the peripheral nervous system ( that is the autonomic nervous system or the somatic nervous system), or malfunctioning of the endocrine system.  The purposes of exposition, the nervous system is divided into the CNS and the peripheral nervous system, although in normal functioning and activities of these two complex systems are integrated, and their actions are further coordinated with activity in the endocrine system. The role of the central nervous system  The brain is estimation to have some 100 billion neurons and thousands of billions of glia cells (presumed to be support cells, although recent evidence suggests that they exert a more active role in neuronal functioning).  These cells group together into anatomically distinct, which appear to have somewhat distinctive functions, although active interconnections throughout the brain indicate that no one area exclusively performs any one function.  Fig 2.1 described the anatomical areas of the brain.  The hindbrain primarily directs the functioning of the autonomic nervous system, which in turn controls primarily internal activities such as digestion, cardiovascular functioning and breathing.  The midbrain is the centre of the reticular activating system, which controls arousal levels (often called sleep-wake center) and thereby attention processes.  The forebrain controls thought, speech, perception, memory, learning and planning- indeed, all of the processes that make us sentient, self – conscious being.  Some disorders have been shown to be directly linked to brain damage  Dementia deterioration in all cognitive processes, particularly memory and learning) that occurs to the loss or ineffective functioning of brain cells.  Losses of brain cell functioning can be transitory, but in many cases they are irreversible and may result from various sources such as direct head injuries, disease, or toxins.  Neurotransmitters are the chemical substances that carry the messages from one neuron to the next in the complex pathway of nervous activity within the brain.  Nerve cells are not connected to one another, so activity in one neuron doesn’t stimulate activity in other neurons.  There is a gap called synapse between the axons or one neuron and the dendrites of neighboring neurons.  The transmission of the electrical activity in the axon to the neighboring dendrites occurs as a result of the release of chemicals called neurotransmitters.  Certain neurons seem to be more sensitive to one or another type of neurotransmitter and these neurons seem to cluster together, forming particular brain circuits.  When neurotransmitters are released into the synapse, some will be taken up at the receptor sites on the dendrites and so it activates it or inhibits it. (Depending on the action of the transmitter) an impulse in the post synaptic neuron.  Within the synaptic cleft are substances that deactivate neurotransmitters, so some of the released transmitters are quickly drawn back into the releasing axon by a process called reuptake.  Thus, abnormal beh can result from disturbance in neurotransmitter systems in various ways: 1. there may be too much or too little of the neurotransmitter produced or released into the synapse; 2. there may be too few or too many receptors on the dendrites 3. There may be an excess or a deficit in the amount of the transmitter- deactivating substance in the synapse; or 4. The reuptake process may be too rapid or too slow.  Any or all of these problems can cause either too much excitation or too much inhibition in the particular brain circuits and this excessive or reduced activity may result in abnormal functioning.  Disturbance in neurotransmitter systems are currently thought more likely to have general rather than specific effects, and it is the interaction of various neurotransmitters and their subtypes that is related to beh.  There is evidence that schizophrenia is caused by excessive dopamine, but this may be a false inference.  Must see focus 2.1 page 28  It is important to note that the processes connecting beh and the neurochemical bases of brain activity do not represent a one way street  No doubt neurotransmitter activity affects beh, but beh also affects neurotransmitter activity  Brain plasticity- It can be influenced by a number of experiences that occur pre and postnatal thru hormones, diet ageing and stress. Disease and maturation. The role of the peripheral nervous system  The peripheral nervous system includes the somatic nervous system which controls the muscles and the autonomic nervous system (ANS). The ANS has two parts: the sympathetic nervous system and the parasympathetic nervous system  These two systems typically function cooperatively to produce homeostatic activity in a variety of bodily functions such as heart rate, digestive and eliminatory processes , sexual arousal, breathing perspiration  In times of stress they function antagonistically: during stress or when a person feels threatened the sympathetic nervous system readies the body for action ( fight or flight) by, eg increasing heart rate, pupil sixe ad breathing.  At the same time the parasympathetic nervous system shuts down digestive processes, since energy given to this function would be wasted in a time of emergency.  In some ppl the ANS response to stress is either exaggerated strong or remarkably weak  See the picture on page 29  The ANS (more particular, the sympathetic nervous system) is involved in fear and anxiety reactions.  Thus the overreaction ANS may increase readiness to acquire phobias or other anxiety disorders, eg it is assumed by some behavioral therapists that conditioning processes are the basis for acquiring anxiety disorders.  The strength of an individual’s ANS response to a frightening experience may determine whether he or she acquires a conditioned phobic reaction. It has been found that there is a heritable component to the level of emotionality  Individual differences in the regulation of various ANS and somatic nervous system functions may also play a part in disordered beh.  Eg when patients diagnosed with generalized anxiety disorder (GAD) tend to show decreased parasympathetic regulation of changes in heart rate and respiration when compared to non- anxiety individuals.  It appears that autonomic and somatic inflexibility may be particularly important to GAD  This inflexibility is seen in the chronic worry exhibited by an individual with GAD The role of the endocrine system  The CNS interacts with the endocrine system in a feedback loop that maintains appropriate levels of hormones circulating in the bloodstream.  Hormones are chemical messengers that are secreted by various glandes  These secretions maintain bodily functioning and play an important role in the development of the organism  The relationship of the endocrine glands both to each other and to the CNS is complex.  The pituitary (which is often called the “master gland” because it plays such as controlling role in activating the other endocrine glands) releases many different hormones, some of which s we have seen, activate other glands while others have a more direct action.  Growth hormones promotes and regulates muscle, bone and other tissue growth; prolactin stimulates mild production in women  Two disorders are known to be related to malfunctioning endocrine glands.  Cretinism, a disorder involving a dwarflike appearance and mental retardation is a result of a defective thyroid gland  Hypoglycemia, which results from the pancreas failing to produce balanced levels of insulin or glycogen, produces experiences that mimic anxiety and some patients who report to anxiety disorder clinics are in fact suffering from hypoglycemia.  One system that has been studied with regards to depression and anxiety is the hypothalamic pituitary- adrenal (HPA) axis. The end result of this intricate system of communication between the hypothalamus, the pituitary gland and the adrenal cortex is the release of cortisol  Cortisol is a hormone that is released into the bloodstream by the adrenal cortex in response to a variety or stressors.  This hormone facilitates an individual’s response to short term threat by producing a number of changes in the body. Genetics and beh  It is reasonable to assuming that most of all beh are the products of an interaction between these sources of influence.  Behavioural genetics – offers us an insight into the biological bases of abnormal functioning.  more research is emp on genotype-environment interaction o IT APPEARS AS THOUGH GENES MAY INFLUECES BEH THAT CONTIVUTE TO ENVIRONEMTS STRESSORS, WHICH INCREASE THE PSYCHOPATHOLOGY.  This type of reciprocal relationship between genetics and env has been found in animals and human studies.  Caspi and colleagues examined the interactive effects of a genotype associated with depression and stressful life events. ( SLE)  The relationship between SLE and depression was much stronger among adults who have short variant of a particular gene related to negative emotionality (5HTTLPR).  There is no direct link between he genotype and depression. … thus adults with this genotype only developed depression if they also experienced SLE’s  Beh research into the genetic bases of psychiatric disorders usually take tree forms: o Family studies, twin studies and adoption studies.  When the problem that characterized the index case also occurs in the comparison person, the two are said to be concordant.  Concordance is thought to reveal the influence of genetics  More recent techniques for studying genetic influences include genetic linkage studies and research methods in molecular biology.  In genetic linkage studies, researchers line families with high incidence of a particular psychotic disorder.  Within these extended families, researchers look
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