lOMoARcPSD| 68366729
CMN 554
Module 4 Primary Study Guide (Personality Disorders) latest
updated 2026/2027 CMN 554
Module 4 Primary Study Guide (Personality Disorders)
Sadock - Chapter 26
Personality (character)
Personality is both complex and unique: on one hand, people differ greatly from one another in multiple
components of behavior, and, on the other hand, each person expresses only one of his or her many potential
lifestyles. The common characteristic of all existing definitions of personality is that they are functional, that is,
they focus on questions related to motivation and mental adaptation of the organism. Specifically, Allport defined
personality as the “dynamic organization within the individual of those psychophysical systems that determine
his/her unique adjustment to his/her environment.”
Allport elaborated on this definition by explaining that the expression “dynamic organization” emphasizes
that personality is an organized system (“unitas multiplex”) that is constantly evolving and changing. The phrase
“within the individual” means that personality refers to intrapsychic processes, not judgmental comparisons of one
person to another. The term “psychophysical” means that personality is neither exclusively mental nor exclusively
neural but a combination of the two. The expression “unique adjustment to the environment” has both functional
and evolutionary significance pointing to personality as a mode of survival and, more generally, learning and
adaptation, which is unique to each individual. Allport’s use of the verb “determine” suggests that personality
traits are determining dispositions that limit a person’s behavioral repertoire.
It is now known that people are self-aware and have enough freedom of will to change their behavior in
directions that are not necessarily predictable or determined by their past. Accordingly, Allport’s definition has
been modified as follows: human personality is the dynamic organization of the psychobiological systems by which
a person shapes and adapts in a unique way to a changing internal and external environment. In other words,
personality is a way of describing the dynamical processes that occur within the person to shape and adapt to life
experiences by self-aware learning and proactive planning. The maturation and integration of human personality
involves one’s growing in self-awareness through experiences across a wide range of situations.
It has been widely accepted that personality develops through the interaction of hereditary dispositions
and environmental influences. Waddington’s notion of genetic canalization (or “epigenetic landscape”) has been
revised to include reciprocal interactions among genetic endowment, environmental stimulation, and changes in
selfawareness across the life span. Genetic differences account for about half of the variance in differences
between people for most normally distributed temperament traits. The remaining 50 percent of the variance in
differences between people is attributed to environmental influences. Most of the environmental influences are
unique to each individual, particularly for temperament traits, but parental rearing and sociocultural norms have a
substantial influence on a person’s character development. Of note, adoption studies suggest somewhat lower
heritability of about 30 percent for personality traits. The higher heritability estimates from twins are the result of
nonadditive genetic influences (e.g., higher-order interaction among alleles at each locus or among loci), which is
the same for monozygotic twins but contributes little to the resemblance of other relatives. Epistasis (i.e.,
interactions among multiple gene loci) is so strong for both temperament and character that it was difficult to
identify specific genes for personality until methods were developed to take epistasis into account.
However, heritability estimates refer only to genetic influences on the differences between people at one
point in time. People are able to change from one time to another as a result of growth in self- awareness in ways
that are only partly constrained by their past genetic expression. For example, intelligence quotient (IQ) is highly
heritable, but there has been increase of about 3.3 IQ points per decade that requires frequent restandardization
of IQ tests. The increase in IQ scores in successive birth cohorts is called the “Flynn effect.” The increase in IQ is
1
, lOMoARcPSD| 68366729
attributable to skill in problem solving on the spot (“fluid intelligence”), such as recognition of similarities, rather
than skills dependent on past individual education, such as vocabulary size (“crystallized intelligence”). Likewise,
the differences between people in Self-Transcendence at one point in time is 49 percent heritable, but the
prevalence of self-transcendent experiences increased from 48 percent in 1987 to 76 percent in 2000 in English
people according to studies of the zoologist David Hay. These rapid changes in fluid intelligence and self-
transcendence cannot be explained by genetic evolution. Character and fluid intelligence can develop rapidly
within individuals in response to cultural developments that influence human society as a whole.
From the structural standpoint, personality can be decomposed into temperament, character, and psyche.
Roughly speaking, temperament involves basic emotions, character involves rational concepts about self and
interpersonal relations, and the psyche involves intuitive self-awareness and fluid intelligence. Self-awareness and
fluid intelligence influence personality development substantially, so measures of temperament and character
provide an incomplete understanding of personality development. Basic functions of personality are to feel, think,
and perceive, and to incorporate these into purposeful behaviors.
Psychobiology of Temperament
Temperament traits of Harm Avoidance, Novelty Seeking, Reward Dependence, and Persistence are
defined as heritable differences underlying one’s automatic response to danger, novelty, social approval, and
intermittent reward, respectively. These four temperament traits are closely associated with the four basic
emotions of fear (Harm Avoidance), anger (Novelty Seeking), attachment (Reward Dependence), and ambition
(Persistence).
Individual differences in temperament and basic emotions modify the processing of sensory information
and shape early learning characteristics, especially associative conditioning of unconscious behavior responses and
preattentive components of perception. Temperament is conceptualized as heritable biases in emotionality and
learning that underlie the acquisition of emotion-based, automatic behavioral traits and habits observable early in
life and relatively stable over one’s life span.
Each of the four major dimensions is a normally distributed quantitative trait, moderately heritable,
observable early in childhood, relatively stable in time, and moderately predictive of adolescent and adult
behavior. The four dimensions have been shown to be genetically homogeneous and independently inherited from
one another in large, independent twin studies in the United States, Australia, Sweden, Korea, and Japan.
Temperamental differences, which are not very stable initially, tend to stabilize during the second and third years
of life.
Accordingly, ratings of these four temperament traits at age 10 to 11 years were moderately predictive of
personality traits at ages 15, 18, and 27 years in a large sample of Swedish children. Whereas character traits
develop in a specific direction toward socially favored cultural norms, the number of people who increase in Harm
Avoidance, Reward Dependence, and Persistence is about the same as the number who decrease, so that the
average of these traits remains the same from ages 20 to 45 years. Novelty Seeking decreases about 10 percent
per decade as a person’s impulse control matures.
The four dimensions have been repeatedly shown to be universal across different cultures, ethnic groups,
and political systems on every inhabited continent. In summary, these aspects of personality are called
temperament because they are heritable, manifest early in life, are developmentally stable, and are consistent in
different cultures. Temperament traits are like crystallized intelligence in that they do not show the rapid changes
within increasing age or across birth cohorts that are observed for fluid intelligence and character traits. Table 26–
1 summarizes contrasting sets of behaviors that distinguish extreme scorers on the four dimensions of
temperament. Note that each extreme of these dimensions has specific adaptive advantages and disadvantages,
so neither high nor low scores inherently mean better adaptation.
The component traits (“facets”) for each of the four temperament dimension have distinct learning
characteristics and correlate more strongly with one another than with other components of temperament. They
share a common source of covariation that is strong and invariant regardless of changes in the environment and
past experience. Each of the four temperament dimensions has unique genetic determinants according to family
and twin studies, as well as studies of genetic associations with specific DNA markers.
The four dimensions of human temperament correspond closely to those observed in other mammals.
Multiple levels in the phylogeny of learning abilities in animals from invertebrates to man indicate that learning has
2
, lOMoARcPSD| 68366729
multiple component processes that are hierarchically organized and interact extensively throughout development
(Fig. 26–1).
In Figure 26–1, temperament corresponds to the processes of sensation, association, and motivation that
underlie the integration of skills and habits based on emotion.
Figure 26–1 is useful to specify the hierarchical phylogenetic and ontogenetic organization of learning and
its relevance to the concepts of temperament and character, not to compare learning in humans at a particular age
to learning in lower animals. Specifically, temperament and character are conceptualized on the basis of two types
of memory and learning that have been described in humans and primates. These are called procedural memory
(i.e., behavioral conditioning) and semantic memory (i.e., long-term propositional or declarative memory).
Temperament (the “emotional core” of personality) involves procedural memory regulated by complex distributed
circuits in the cortico-striatolimbic system, primarily the sensory cortical areas, amygdala, and the caudate and the
putamen. Procedural memory underlies associative learning and involves presemantic perceptual processing of
visuospatial information and affective valence that can operate independently of abstract conceptual and/or
volitional processes. In contrast, semantic learning involves higher cognitive functions of abstraction and
symbolization. These two systems of learning and memory can be dissociated functionally from one another and
also from a third memory system that is unique to human beings, as discussed later.
Neurobiological studies of animals have been highly informative about the functional organization of brain
systems underlying procedural learning and temperament. The explicit animal models that were originally
described on the basis of extensive work in rodents and other nonprimates provided hypotheses that have
recently been confirmed by extensive work in humans using modern techniques of brain imaging, neurochemistry,
and neurogenetics. The most comprehensive neurobiological model of learning in animals that has been
systematically related to the structure of human temperament is summarized in Table 26–2. This model
distinguishes four dissociable brain systems for behavioral inhibition (Harm Avoidance), behavioral activation
(Novelty Seeking), social attachment (Reward Dependence), and partial reinforcement (Persistence).
The psychobiology of Harm Avoidance, Novelty Seeking, Reward Dependence, and Persistence is briefly
described later.
3
, lOMoARcPSD| 68366729
Novelty seeking: antisocial, histrionic
Reward dependence: schizoid personality
Harm Avoidance
Harm Avoidance involves a heritable bias in the inhibition of behavior in response to signals of
punishment and frustrative nonreward. It is observed as fear of uncertainty, shyness, social inhibition, passive
avoidance of problems/danger, rapid fatigability, and pessimistic worry in anticipation of problems even in
situations that do not worry other people. Adaptive advantages of high Harm Avoidance are cautiousness and
careful planning when hazard is likely. The disadvantages occur when hazard is unlikely but still is anticipated,
which leads to maladaptive inhibition and anxiety. People low in Harm Avoidance are carefree, courageous,
energetic, outgoing, and optimistic even in situations that worry most people. The advantages of low Harm
Avoidance are confidence in the face of danger and uncertainty, leading to optimistic and energetic efforts with
little or no distress. The disadvantages are related to unresponsiveness to danger or unrealistic optimism with
potentially severe consequences when hazard is likely. The psychobiology of Harm Avoidance is complex. In animal
studies, ascending serotonergic projections from the dorsal raphe nuclei to the substantia nigra inhibit nigrostriatal
dopaminergic neurons and are essential for conditioned inhibition of activity by signals of punishment and
frustrative nonreward. Benzodiazepines disinhibit passive avoidance conditioning by gamma-aminobutyric acid
(GABA)-ergic inhibition of serotonergic neurons originating in the dorsal raphe nuclei. The anterior serotonergic
cells in the dorsal raphe nucleus intermingle with the dopaminergic cells of the ventral tegmental area and both
groups innervate the same structures (e.g., basal ganglia, accumbens, amygdala), providing opposing
dopaminergic–serotonergic influences in the modulation of approach and avoidance behavior. The anterior
serotonergic projections from the dorsal raphe to striatum, accumbens, amygdala, and frontal cortex are usually
4
CMN 554
Module 4 Primary Study Guide (Personality Disorders) latest
updated 2026/2027 CMN 554
Module 4 Primary Study Guide (Personality Disorders)
Sadock - Chapter 26
Personality (character)
Personality is both complex and unique: on one hand, people differ greatly from one another in multiple
components of behavior, and, on the other hand, each person expresses only one of his or her many potential
lifestyles. The common characteristic of all existing definitions of personality is that they are functional, that is,
they focus on questions related to motivation and mental adaptation of the organism. Specifically, Allport defined
personality as the “dynamic organization within the individual of those psychophysical systems that determine
his/her unique adjustment to his/her environment.”
Allport elaborated on this definition by explaining that the expression “dynamic organization” emphasizes
that personality is an organized system (“unitas multiplex”) that is constantly evolving and changing. The phrase
“within the individual” means that personality refers to intrapsychic processes, not judgmental comparisons of one
person to another. The term “psychophysical” means that personality is neither exclusively mental nor exclusively
neural but a combination of the two. The expression “unique adjustment to the environment” has both functional
and evolutionary significance pointing to personality as a mode of survival and, more generally, learning and
adaptation, which is unique to each individual. Allport’s use of the verb “determine” suggests that personality
traits are determining dispositions that limit a person’s behavioral repertoire.
It is now known that people are self-aware and have enough freedom of will to change their behavior in
directions that are not necessarily predictable or determined by their past. Accordingly, Allport’s definition has
been modified as follows: human personality is the dynamic organization of the psychobiological systems by which
a person shapes and adapts in a unique way to a changing internal and external environment. In other words,
personality is a way of describing the dynamical processes that occur within the person to shape and adapt to life
experiences by self-aware learning and proactive planning. The maturation and integration of human personality
involves one’s growing in self-awareness through experiences across a wide range of situations.
It has been widely accepted that personality develops through the interaction of hereditary dispositions
and environmental influences. Waddington’s notion of genetic canalization (or “epigenetic landscape”) has been
revised to include reciprocal interactions among genetic endowment, environmental stimulation, and changes in
selfawareness across the life span. Genetic differences account for about half of the variance in differences
between people for most normally distributed temperament traits. The remaining 50 percent of the variance in
differences between people is attributed to environmental influences. Most of the environmental influences are
unique to each individual, particularly for temperament traits, but parental rearing and sociocultural norms have a
substantial influence on a person’s character development. Of note, adoption studies suggest somewhat lower
heritability of about 30 percent for personality traits. The higher heritability estimates from twins are the result of
nonadditive genetic influences (e.g., higher-order interaction among alleles at each locus or among loci), which is
the same for monozygotic twins but contributes little to the resemblance of other relatives. Epistasis (i.e.,
interactions among multiple gene loci) is so strong for both temperament and character that it was difficult to
identify specific genes for personality until methods were developed to take epistasis into account.
However, heritability estimates refer only to genetic influences on the differences between people at one
point in time. People are able to change from one time to another as a result of growth in self- awareness in ways
that are only partly constrained by their past genetic expression. For example, intelligence quotient (IQ) is highly
heritable, but there has been increase of about 3.3 IQ points per decade that requires frequent restandardization
of IQ tests. The increase in IQ scores in successive birth cohorts is called the “Flynn effect.” The increase in IQ is
1
, lOMoARcPSD| 68366729
attributable to skill in problem solving on the spot (“fluid intelligence”), such as recognition of similarities, rather
than skills dependent on past individual education, such as vocabulary size (“crystallized intelligence”). Likewise,
the differences between people in Self-Transcendence at one point in time is 49 percent heritable, but the
prevalence of self-transcendent experiences increased from 48 percent in 1987 to 76 percent in 2000 in English
people according to studies of the zoologist David Hay. These rapid changes in fluid intelligence and self-
transcendence cannot be explained by genetic evolution. Character and fluid intelligence can develop rapidly
within individuals in response to cultural developments that influence human society as a whole.
From the structural standpoint, personality can be decomposed into temperament, character, and psyche.
Roughly speaking, temperament involves basic emotions, character involves rational concepts about self and
interpersonal relations, and the psyche involves intuitive self-awareness and fluid intelligence. Self-awareness and
fluid intelligence influence personality development substantially, so measures of temperament and character
provide an incomplete understanding of personality development. Basic functions of personality are to feel, think,
and perceive, and to incorporate these into purposeful behaviors.
Psychobiology of Temperament
Temperament traits of Harm Avoidance, Novelty Seeking, Reward Dependence, and Persistence are
defined as heritable differences underlying one’s automatic response to danger, novelty, social approval, and
intermittent reward, respectively. These four temperament traits are closely associated with the four basic
emotions of fear (Harm Avoidance), anger (Novelty Seeking), attachment (Reward Dependence), and ambition
(Persistence).
Individual differences in temperament and basic emotions modify the processing of sensory information
and shape early learning characteristics, especially associative conditioning of unconscious behavior responses and
preattentive components of perception. Temperament is conceptualized as heritable biases in emotionality and
learning that underlie the acquisition of emotion-based, automatic behavioral traits and habits observable early in
life and relatively stable over one’s life span.
Each of the four major dimensions is a normally distributed quantitative trait, moderately heritable,
observable early in childhood, relatively stable in time, and moderately predictive of adolescent and adult
behavior. The four dimensions have been shown to be genetically homogeneous and independently inherited from
one another in large, independent twin studies in the United States, Australia, Sweden, Korea, and Japan.
Temperamental differences, which are not very stable initially, tend to stabilize during the second and third years
of life.
Accordingly, ratings of these four temperament traits at age 10 to 11 years were moderately predictive of
personality traits at ages 15, 18, and 27 years in a large sample of Swedish children. Whereas character traits
develop in a specific direction toward socially favored cultural norms, the number of people who increase in Harm
Avoidance, Reward Dependence, and Persistence is about the same as the number who decrease, so that the
average of these traits remains the same from ages 20 to 45 years. Novelty Seeking decreases about 10 percent
per decade as a person’s impulse control matures.
The four dimensions have been repeatedly shown to be universal across different cultures, ethnic groups,
and political systems on every inhabited continent. In summary, these aspects of personality are called
temperament because they are heritable, manifest early in life, are developmentally stable, and are consistent in
different cultures. Temperament traits are like crystallized intelligence in that they do not show the rapid changes
within increasing age or across birth cohorts that are observed for fluid intelligence and character traits. Table 26–
1 summarizes contrasting sets of behaviors that distinguish extreme scorers on the four dimensions of
temperament. Note that each extreme of these dimensions has specific adaptive advantages and disadvantages,
so neither high nor low scores inherently mean better adaptation.
The component traits (“facets”) for each of the four temperament dimension have distinct learning
characteristics and correlate more strongly with one another than with other components of temperament. They
share a common source of covariation that is strong and invariant regardless of changes in the environment and
past experience. Each of the four temperament dimensions has unique genetic determinants according to family
and twin studies, as well as studies of genetic associations with specific DNA markers.
The four dimensions of human temperament correspond closely to those observed in other mammals.
Multiple levels in the phylogeny of learning abilities in animals from invertebrates to man indicate that learning has
2
, lOMoARcPSD| 68366729
multiple component processes that are hierarchically organized and interact extensively throughout development
(Fig. 26–1).
In Figure 26–1, temperament corresponds to the processes of sensation, association, and motivation that
underlie the integration of skills and habits based on emotion.
Figure 26–1 is useful to specify the hierarchical phylogenetic and ontogenetic organization of learning and
its relevance to the concepts of temperament and character, not to compare learning in humans at a particular age
to learning in lower animals. Specifically, temperament and character are conceptualized on the basis of two types
of memory and learning that have been described in humans and primates. These are called procedural memory
(i.e., behavioral conditioning) and semantic memory (i.e., long-term propositional or declarative memory).
Temperament (the “emotional core” of personality) involves procedural memory regulated by complex distributed
circuits in the cortico-striatolimbic system, primarily the sensory cortical areas, amygdala, and the caudate and the
putamen. Procedural memory underlies associative learning and involves presemantic perceptual processing of
visuospatial information and affective valence that can operate independently of abstract conceptual and/or
volitional processes. In contrast, semantic learning involves higher cognitive functions of abstraction and
symbolization. These two systems of learning and memory can be dissociated functionally from one another and
also from a third memory system that is unique to human beings, as discussed later.
Neurobiological studies of animals have been highly informative about the functional organization of brain
systems underlying procedural learning and temperament. The explicit animal models that were originally
described on the basis of extensive work in rodents and other nonprimates provided hypotheses that have
recently been confirmed by extensive work in humans using modern techniques of brain imaging, neurochemistry,
and neurogenetics. The most comprehensive neurobiological model of learning in animals that has been
systematically related to the structure of human temperament is summarized in Table 26–2. This model
distinguishes four dissociable brain systems for behavioral inhibition (Harm Avoidance), behavioral activation
(Novelty Seeking), social attachment (Reward Dependence), and partial reinforcement (Persistence).
The psychobiology of Harm Avoidance, Novelty Seeking, Reward Dependence, and Persistence is briefly
described later.
3
, lOMoARcPSD| 68366729
Novelty seeking: antisocial, histrionic
Reward dependence: schizoid personality
Harm Avoidance
Harm Avoidance involves a heritable bias in the inhibition of behavior in response to signals of
punishment and frustrative nonreward. It is observed as fear of uncertainty, shyness, social inhibition, passive
avoidance of problems/danger, rapid fatigability, and pessimistic worry in anticipation of problems even in
situations that do not worry other people. Adaptive advantages of high Harm Avoidance are cautiousness and
careful planning when hazard is likely. The disadvantages occur when hazard is unlikely but still is anticipated,
which leads to maladaptive inhibition and anxiety. People low in Harm Avoidance are carefree, courageous,
energetic, outgoing, and optimistic even in situations that worry most people. The advantages of low Harm
Avoidance are confidence in the face of danger and uncertainty, leading to optimistic and energetic efforts with
little or no distress. The disadvantages are related to unresponsiveness to danger or unrealistic optimism with
potentially severe consequences when hazard is likely. The psychobiology of Harm Avoidance is complex. In animal
studies, ascending serotonergic projections from the dorsal raphe nuclei to the substantia nigra inhibit nigrostriatal
dopaminergic neurons and are essential for conditioned inhibition of activity by signals of punishment and
frustrative nonreward. Benzodiazepines disinhibit passive avoidance conditioning by gamma-aminobutyric acid
(GABA)-ergic inhibition of serotonergic neurons originating in the dorsal raphe nuclei. The anterior serotonergic
cells in the dorsal raphe nucleus intermingle with the dopaminergic cells of the ventral tegmental area and both
groups innervate the same structures (e.g., basal ganglia, accumbens, amygdala), providing opposing
dopaminergic–serotonergic influences in the modulation of approach and avoidance behavior. The anterior
serotonergic projections from the dorsal raphe to striatum, accumbens, amygdala, and frontal cortex are usually
4
