Causal Factors and Viewpoints
Etiology: Causal patter of abnormal behaviour.
Necessary Cause: a condition that must exist for a disorder to occur. If Disorder Y
occurs, then Cause X must have preceded it.
Ex) General paresis—a degenerative brain disorder—(Y) cannot develop unless a
person has previously contracted syphilis (X).
Sufficient Cause: a condition that guarantees the occurrence of a disorder. If Cause X
occurs, then Disorder Y will also occur. A sufficient cause may not need a necessary
Ex) Hopelessness (X) is a sufficient cause of depression.
Contributory Cause: a condition that increases the probability of the development of a
disorder but is neither necessary nor sufficient for the disorder to occur. If X occurs, then
the probability of Disorder Y increases.
Ex) Parental rejection (X) could increase the probability that a child will later
have difficulty in handling close personal relationships (Y).
o Distal causal factors may not show their effects for many years and may
contribute to a predisposition to develop a disorder.
o Proximal causal factors operate shortly before the occurrence of the symptoms of
o A reinforcing contributory cause is a condition that tends to maintain maladaptive
behaviour that is already occurring.
o Diathesis = predisposition or vulnerability to developing a given disorder.
o Views abnormal behaviour as the result of stress operating on an individual who
has a biological, psychosocial, or sociocultural predisposition to developing a
o Interactive and additive models of diathesis-stress interaction (p.65)
Protective Factors: 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.
Resilience: the ability to adapt successfully to even very difficult circumstances.
Biopsychosocial Viewpoint: Acknowledges that biological, psychological, and
sociocultural factors all interact and play a role in psychopathology and treatment.
The Biological Viewpoint and Biological Causal Factors
1) Neurotransmitter and Hormonal Imbalances in the Brain
Neurotransmitters: chemical substances that are released into the synapse by the
presynaptic neuron when a nerve impulse occurs. Some NTs increase the likelihood that
the postsynaptic neuron will fire while others inhibit the impulse.
Neurotransmitter imbalances occur if there is excessive production and release of NT,
dysfunctions in the process of NT deactivation, or problems with the receptors in the
postsynaptic neuron. Hormones: chemical messengers secreted by a set of endocrine glands in our bodies.
Hypothalamic-Pituitary-Adrenal-Cortical Axis: Negative feedback system involving
the hypothalamus and pituitary. Malfunctioning of this system has been implicated in
various forms of psychopathology, such as depression and PTSD.
i. CRH travels from the hypothalamus to the pituitary.
ii. In response to CRH, the pituitary releases ACTH, which stimulates the cortical
part of the adrenal gland to produce norepinephrine and cortisol.
iii. Cortisol provides negative feedback to the hypothalamus and pituitary to decrease
their release of CRH and ACTH, which in turn reduces the release of
norepinephrine and cortisol.
2) Genetic vulnerabilities
Behaviour and psychological disorders are not determined exclusively by genes.
However, most psychological disorders show at least some genetic influence ranging
from small to large.
Genotype: A person’s total genetic endowment.
Phenotype: Observed structural and functional characteristics that result from an
interaction of the genotype and the environment.
Genotype-Environment Correlations: Genotypic vulnerability that can shape a child’s
environmental experiences. The genotype may have a passive effect, evocative effect, or
active effect on the environment.
Genotype-Environment Interaction: Differential sensitivity or susceptibility to their
environments by people who have different genotypes.
Methods for studying behaviour genetics (heritability of psychological disorders) include
the family history (pedigree) method, the twin method, the adoption method, linkage
analysis, and association studies.
Linkage Analysis: Genetic research strategy in which occurrence of a disorder in an
extended family is compared with that of a genetic marker for a physical characteristic or
biological process that is known to be located on a particular chromosome.
Association Studies: Genetic research strategy comparing frequency of certain genetic
markers known to be located on particular chromosomes in people with and without a
Temperament refers to a child’s reactivity and characteristic ways of self-regulation.
There are five dimensions of temperament:
o Fearfulness (neuroticism in adults)
o Irritability and frustration (neuroticism in adults)
o Positive affect (extroversion in adults)
o Activity level (extroversion in adults)
o Attentional persistence (constraint or control in adults) 4) Brain dysfunction and neural plasticity
Neural Plasticity: Flexibility of the brain in making changes in organization and/or
function in response to pre- and postnatal experiences, stress, diet, disease, drugs,
Developmental Systems Approach: Acknowledges not only that genetic activity
influences neural activity, which in turn influences behaviour, which in turn influences
the environment, but also that these influences are bidirectional. Various aspects of our
environment (physical, social, cultural) also influence our behaviour, which then affects
out neural activity, and this in turn can influence genetic activity.
The Psychosocial Viewpoint and Psychosocial Causal Factors
Attempts to understand humans not just as biological organisms but also as people with
motives, desires, and perceptions. The three major psychosocial perspectives are
psychodynamic, behavioural, and cognitive-behavioural. Two other perspectives are the
humanistic perspective and the existential perspective.
1) Psychodynamic Perspective
o Focus on the unconscious aspects of human behaviour
o The structure of personality consists of
- The id – inst