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Abnormal Psychology – Unit 3 Summary
Causal Factors and Viewpoints
The search for causes of psychological abnormality is embedded in theories of what should influence psychological
functioning. Theories emerge for several reasons:
1. To explain the cause of the problem;
2. To identify the factors that maintain the problem;
3. To predict the course of the problem; and
4. To guide the development of effective treatment for the problem.
Theories differ in the perspective and emphasis. What draws a person to one theory or another and which one is 'right'?
Ideally it should be a theory's soundness, refutabililty, and potential for contribution that holds the draw, but there are
other factors too.
For example, our own personal interests and experiences always influence us. If you experienced bullying as a child and
suffered through years of terrible nightmares as a result, you might have a stronger interest in the relationship between
psycho-social events and internal, psychological experiences. If you've experienced how dramatically chemicals can
influence the very elements of your personality, perhaps you might be more curious about the chemical influences of the
Another draw towards a particular theoretical orientation is the social climate in which you were raised. For example,
people raised in the 1970s probably absorbed the social-learning perspective of that time, and believe that if treated with
kindness and respect, all people will develop into strong healthy individuals. This would orient them towards models that
emphasize the role of environment and relationships in human development.
Beginning in the 1990s there were giant leaps in the fields of biotechnology and the human genome project. People raised
in this era probably absorbed the emphasis on biology and the unprecedented tendency to look to medicine to correct
certain psychological experiences, like depression. (There was an astounding increase in the use of antidepressants at this
Take a few minutes now to think about your own beliefs about what causes abnormal behaviour and psychological
Read pages 62-68 in your text to learn about the general issues around causal factors and viewpoints.
Etiology – causal pattern of abnormal behavior
A necessary cause (e.g., cause X) is a condition that must exist for a disorder (e.g., disorder Y to occur).
A sufficient cause (e.g., cause X) of a disorder is a condition that guarantees the occurrence of a disorder (e.g.,
disorder Y).
A sufficient cause may not be a necessary cause.
A contributory cause (e.g., cause X) is one that increases the probability of the development of a disorder (e.g.,
disorder Y) but is neither necessary nor sufficient for the disorder to occur.
Some causal factors occurring relatively early in life may not show their effects for many years; these would be
considered distal causal factors that may contribute to a predisposition to develop a disorder.
Other causal factors operate shortly before the occurrence of the symptoms of a disorder; these would be
considered proximal causal factors.
oSometimes a proximal causal factor may be a condition that proves too much for a person and triggers the
onset of a disorder.
A reinforcing contributory cause is a condition that tends to maintain maladaptive behavior that is already
When more than one causal factor is involved, the term causal factor has been used.
A predisposition or vulnerability toward developing a disorder is termed a diathesis.
Many psychological disorders are believed to develop as the result of some kind of stressor operating on a person
who has a diathesis or vulnerability for that disorder. Hence these theories are commonly known as diathesis-
stress models of abnormal behavior.
Stress usually occurs when an individual experiences chronic or episodic events that are undesirable.
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Factors contributing to the development of a diathesis are themselves sometimes highly potent stressors, such as
when a child experiences the death of a parent, and may thereby acquire a predisposition or diathesis for
becoming depressed later in life.
In what is called the additive model, individuals who have a high level of a diathesis may need only a small
amount of stress before a disorder develops; but those who have a very low level of a diathesis may need to
experience a large amount of stress for a disorder to develop.
A person with no diathesis or a very low level of diathesis could still develop a disorder when faced with truly
severe stress. In what is called an interactive model, some amount of diathesis must be present before stress will
have any effect. Thus, in the interactive model, someone with no diathesis will never develop the disorder, no
matter how much stress he or she experiences.
Protective factors are influences that modify a person’s response to environmental stressors, making it less likely
that the person will experience the adverse consequences of the stressors.
oProtective factors are not necessarily positive experiences.
oSome protective factors have nothing to do with experiences at all but are simply some quality or attribute
of a person.
Protective factors most often, but not always, lead to resilience – the ability to adapt successfully to even very
difficult circumstances.
The term resilience has been used to describe three distinct phenomena: (1) good outcomes despite high-risk
status. (2) sustained competence under threat, and (3) recovery from trauma.
Developmental psychopathology focuses on determining what is abnormal at any point in development by
comparing and contrasting it with the normal and expected changes that occur in the course of development.
The biopsychosocial viewpoint acknowledges that biological, psychosocial, and sociocultural factors all play a
role in psychopathology and treatment.
Biological Models
Most researchers today recognize that there are not 'competing' models. A scientist focusing on biological causal factors
would certainly acknowledge that psychological and sociocultural factors play a role as well. People just focus on
different things. Even within a biological model, there are different areas of focus. Some emphasize the structural models
in the brain, some emphasize the role of neurotransmitter systems, while others look to hormonal and autonomic nervous
systems functioning. Some biological models consider genetic make up to be the primary influence in abnormal
One of the problems encountered in some biological models is that the effect is sometimes used to predict the cause. Just
because a person responds to certain chemical alterations does not necessarily mean that the disorder was 'caused' by that
chemical. Penicillin cures bacterial infections, but it does not mean that a deficiency of penicillin is the cause of bacterial
infections (bacteria are).
It is important to remember, in any area, that the cure does not always prove the cause.
Read pages 68-78 in the text to learn about the biological viewpoint and biological causal factors.
The site of communication between the axon of one neuron and the dendrites or cell body of another neuron is the
synapse – a tiny fluid-filled space between neurons. These interneural transmissions are accomplished by
neurotransmitters – chemical substances that are released into the synapse by the presynaptic neuron when a
nerve impulse occurs.
The belief that neurotransmitter imbalances in the brain can result in abnormal behavior is one of the basic tenets
of the biological perspective today.
oSometimes psychological stress can bring on neurotransmitter imbalances. These imbalances can be
created in a variety of ways:
1. There may be excessive production and release of the neurotransmitter substance into the synapses
causing a functional excess in levels of that neurotransmitter.
2. There may be dysfunctions in the normal processes by which neurotransmitters, once released into the
synapse, are deactivated. Ordinarily, this deactivation occurs either through a process of reuptake of
the released neurotransmitter from the synapse into the axon ending, or through a process of
degradation by certain enzymes that may be present in the sunpse and in the presynaptic axon ending.
3. Finally, there may be problems with the receptors in the postsynaptic neuron, which may be either
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abnormally sensitive or abnormally insensitive.
Neurons that are sensitive to a particular neurotransmitter tend to cluster together, forming neural pathways
between different parts of the brain known as chemical circuits.
Four different kinds of neurotransmitters have been most extensively studied in relation to psychopathology: (1)
norepinephrine (noradrenaline), (2) dopamine, (3) serotonin, and (4) gamma aminobutyric acid (GABA). The first
three belong to a class of neurotransmitters called monamines because each is synthesized from a single amino
acid (monoamine means one amine).
1. Norepinephrine has been implicated as playing an important role in the emergency reactions our bodies show
when we are exposed to an acutely stressful or dangerous situation.
2. Dopamine has been implicated in schizophrenia as well as in addictive disorders.
3. Serotonin has been found to have important effects on the way we think and process information form our
environment, as well as on behaviours and moods. It seems to play a role in emotional disorders such as
anxiety and depression, as well as in suicide.
4. GABA is strongly implicated in reducing anxiety, as well as other emotional states characterized by high
levels of arousal.
Hormones are chemical messengers secreted by a set of endocrine glands in our bodies.
The pituitary gland, which is the master gland of the body, produces a variety of hormones that regulate or
control the other endocrine glands.
One particularly important set of interactions occurs in the hypothalamic-pituitary-adrenal-cortical axis.
Activation of this axis involves:
1. Messages in the form of corticotropin-releasing hormone (CRH) travel from the hypothalamus to the
2. In response to CRH, the pituitary releases adrenocorticotrophic hormone (ACTH), which stimulates the
cortical part of the adrenal gland (located on top of the kidney) to produce epinephrine (adrenaline) and the
stress hormone cortisol. Cortisol mobilizes the body to deal with stress.
3. Cortisol in turn provides negative feedback to the hypothalamus and pituitary to decrease their release of
CRH and ACTH, which in turn reduces the release of adrenaline and cortisol. This negative feedback system
operates much as a thermostat does to regulate temperature.
The gonadal glands produce sex hormones, and imbalance in these can also contribute to maladaptive behavior.
Biochemical processes are affected by genes, which consist of very long molecules of DNA and are present at
various locations on chromosomes.
Chromosomes are the chain-like structures within a cell nucleus that contain the genes. Genes are carriers of
genetic information that we inherit from our parents and other ancestors.
Personality traits and psychological disorders are not affected by chromosomal abnormalities per se, but rather by
abnormalities in some of the genes on the chromosomes.
Vulnerabilities to psychological disorders are almost always polygenic, which means multiple genes influence
A person’s total genetic endowment is referred to as her or his genotype.
The observed structural and functional characteristics of the genotype and the environment are referred to as a
person’s phenotype.
In some cases, the genetic vulnerability present at birth does not exert its effect on the phenotype until much later
in life.
Genotype-environment correlation – genotypic vulnerability that can shape a child’s environmental
Researchers have found three important ways in which an individual’s genotype may shape his or her
1. The genotype may have what has been termed a passive effect on the environment resulting from the genetic
similarity of parents and children.
2. The child’s genotype may evoke particular kinds of reactions from the social and physical environment – a
so-called evocative effect.
3. The child’s genotype may play a more active role in shaping the environment – a so-called active effect. In
this case, the child seeks out or builds an environment that is congenial – a phenomenon known as niche
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