Personality and Psychopathology
Head: Dr. Michael Bagby
Research in this area centres around identifying alternative structures
of personality psychopathology; applying "normal" dimensions
of personality as modulating variables in the treatment of major depression;
studying the relationship between cognitive and neurocognitive variables
with dimensions of personality; developing tests and scales; and providing
an objective psychological assessment of malingering. Dr. Michael Bagby
continues to fund this research through various national and international
awards from such agencies as the Ontario Mental Health Foundation, the
National Institutes of Health and the Social Sciences and Humanities Research
Council. Dr. Bagby has recently been joined by Dr. Peter Farvolden, with
whom he will be collaborating on these and other new projects.
Psychobiological Studies
Vulnerability to stress, dysregulation of sleep and dysregulation of
appetite and weight are of fundamental importance in understanding and
treating mood and anxiety disorders. Dr. Robert Levitan has received ongoing
funding from a number of federal and provincial agencies to study cortisol
in adult and infant populations. Perturbation studies of the serotonin
system have been completed across a spectrum of populations, including
people with bulimia nervosa, seasonal affective disorder and post-stroke
depression. Sleep studies in people with depression have also been carried
out in collaboration with Dr. Colin Shapiro. Dr. Roger McIntyre has received
funding to study underlying mechanisms of weight gain following treatment
with antipsychotic and anticonvulsant agents and is focusing his research
on the roles of leptin and reproductive hormone changes. Dr. McIntyre
is also collaborating with Dr. James Kennedy to identify candidate genes
that increase the risk for weight gain.
Application of the Five-Factor
Model of Personality to Psychopathology
Recognition of the limitations associated with the categorical approach
to personality psychopathology has led to the development of several new
dimensional models of personality psychopathology. Our research attempts
to determine whether the dimensions of personality represented by the
Five-Factor Model of Personality can be applied successfully to a variety
of patient samples and used to better understand the relevant neurobiology,
psychopharmacology and structure of personality psychopathology.
Relationship between
Stability and Change in Personality
In determining whether personality traits confer a specific and enhanced
vulnerability to the development of psychiatric disorders, one of the
more vexing problems is: how do we reliably assess traits in the context
of acute illness?
We have made an important contribution in this area by outlining the
differences between absolute and relative stability of personality traits
and introducing equally important issues related to personality stability
-- ipsative and factorial stability. A project is currently under way
that examines these types of stability issues in patients with depression,
before and after treatment.
Neurotransmitter Mechanisms
in Modulating Dimensions of Personality
We are interested in understanding the relationship between dimensions
of personality and specific neurotransmitters (serotonin, dopamine and
norepinephrine). For example, it has been hypothesized that serotonergic
mechanisms modulate dimensions of personality related to hostility and
affiliative behaviour. Although different studies have produced inconsistent
results, two ongoing studies address some of the methodological problems
we believe are responsible for the inconsistencies.
Personality as a Predictor
of Recurrent Major Depressive Episodes
It has become increasingly evident that a large proportion of people
successfully treated for depression experience a recurrent episode following
several months of remission. Although a considerable number of studies
have examined the role of personality psychopathology in the onset and
treatment of depression, few have explored its role in recurrent depression.
A project is currently under way to examine the role of personality psychopathology
as a contributing factor to depressive illness.
Personality, Limbic-Cortical
Function and Vulnerability to Major Depression and Other Imaging Studies
This project attempts to unify two parallel lines of research examining
vulnerability to depression. One line shows that PET scans in patients
with depression display specific patterns to induced sad mood; the other
shows that individuals who have a high score on "neuroticism"
are vulnerable to develop depression. Our research examines whether never-depressed
"normal" subjects with high neuroticism scores show the same
response as people who are depressed or were previously depressed.
Other ongoing PET studies are examining specific receptor occupancy and
the relation to personality traits thought to be regulated by these specific
receptors.
Personality as a Mediator
of Treatment Outcome
This project examines whether different types of personality traits (dependency
and self-criticism) moderate and/or mediate treatment outcome differently
in three standard and empirically established effective interventions
for depression (interpersonal therapy, cognitive-behavioural therapy and
pharmacotherapy). Previous studies have demonstrated that all these treatments
are about equally effective, but no study has systematically examined
whether targeting depressive symptoms related to personality traits mediates
outcome differently.
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