PhD (Clinical) Research Project Student Investigator: James Collett
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Transcript of PhD (Clinical) Research Project Student Investigator: James Collett
The Relationship Between Goal-Oriented Motivation
and Mood Variability: Implications for Bipolar
DisorderPhD (Clinical) Research Project
Student Investigator: James CollettPrimary Supervisor: Greg Murray
Secondary Supervisor: Conrad Perry
Part I: Historical Perspective, Aetiology, and Spectrum Theories of Bipolar Disorder
Bipolar Disorder Classified as an affective disorder. Can consist of:- Manic episodes- Depressive episodes - Mixed episodes- Occurrence of hypomania- Returns to euthymic mood Unipolar mania considered to be
spurious.
History Piquer (1759), Falret (1854), Baillarger
(1854), Kraepelin (1899): Dual-form insanity and manic-depressive illness.
Kraepelin (1899): Cyclicity and recurrence originally prioritised.
Leonhard (1957): Term “bipolar” applied, bipolar depression differentiated from unipolar depression.
Idea of reactive versus recurrent depression. American Psychiatric Association (2000):
DSM approach emphasises component episodes.
Modern Affective Disorders
The DSM-5 contains several categories of recurrent affective disorder:
- Bipolar I Disorder- Bipolar II Disorder- Major Depressive Disorder- Cyclothymia- Persistent Depressive Disorder
(Dysthymia)- Disruptive Mood Dysregulation Disorder
Causes of Bipolar Disorder Several factors have been suggested as
being involved in the causation and exacerbation of bipolar disorder:
- Evolutionary theories- Manic defence versus primacy-of-mania
hypotheses- Genetic linkage- Monoamine hypothesis- Circadian rhythm hypothesis- Social rhythm hypothesis- Behavioural activation system (BAS)
hypersensitivity model
Diathesis-Stress Model Like most mental disorders, bipolar disorder
can be conceptualised under a diathesis-stress (vulnerability-trigger) model.
Can think of disorders as differing in their balance of diathesis versus stress.
Bipolar disorder appears to be weighted more towards diathesis, but episodic nature often keyed to exogenous environmental stressors.
Kindling effect observed where occurrence of mood episodes may become more endogenous over time.
Spectrum Model As with many disorders, bipolar disorder
can be thought of as occurring on a quantitative spectrum with normal mood.
Vulnerability trait of emotion dysregulation.
Difference between being sad versus being depressed, and between being energised and being manic.
Extremes of vulnerability trait more likely to be defined as being of clinical severity.
Separability of Mania and Depression
It is useful to separate mania and depression as distinct vulnerability traits:
- Concordant with factor analytic evidence- Allows ranking of affective diagnoses based
on severity- Facilitates explanation of reactive and
recurrent unipolar depressions- Enhances sensibility of mixed episodes- Provides more complex diagnostic groups
(Md, MD, Dm, md)
Bipolar Disorder is Not Bipolar
versus
versus
Mania
Depression
Mania
Depression
&
Trait or State? If bipolar disorder involves extreme mood
states, this raises question of how traits (dispositional) and states (transient) interact.
Can view traits as underlying predispositions towards certain states.
Can also view traits as signifying that baseline personality is likely to be characterised by state attributes.
Research attempting complex state-trait models of affective disorder is still in its infancy.
Arguments for Trait Approach
There are several reasons why examining bipolar disorder vulnerability as a personality trait can be useful:
- Supports evolutionary retention of disorder traits as adaptive
- Matches multifactorial nature of genetic transmission- Permits much larger sample sizes- Allows for research that avoids prodomal and residual
state effects and pharmacological “scarring” effects- Avoids over-stigmatising bipolar disorder and
conceptualising it as wholly alien to “normal” human experience
Arguments against Trait Approach
While the trait approach is useful, it is important to keep in mind the following caveats:
- The treatment model for bipolar disorder is dominantly medical, possibly implying a biologically distinct disorder
- Interaction between both quantitative and qualitative factors
- Research does not always replicate findings between clinical and non-clinical samples
- Trait content is usually developed from a top-down clinic perspective, and hence may be out of touch with non-clinical trait expressions (resulting in pronounced positive skew).
Part II: Project examining Bipolar Disorder and BAS Sensitivity in a Non-Clinical Sample
Current Project Attempts to establish and explain the
relationship between trait bipolar disorder and reward sensitivity using Reinforcement Sensitivity Theory (RST).
Examines correlations between bipolar disorder traits and RST traits.
Assesses how traits influence behavioural task performance.
Explores how mood state manipulation interacts with traits to alter behavioural task performance.
Links between BAS and BD
By definition, mania is a state of almost pure BAS. Similar physiological systems (largely dopaminergic)
have been implicated. BAS sensitivity has been observed in euthymic
bipolar disorder. Elevated BAS scores predictive of bipolar disorder
onset and of greater frequency of mania once diagnosed.
Individuals with bipolar disorder experience greater mobilization in response to goal progress (whereas non-psychiatric controls more likely to decrease effort if goal progress is going well).
Measurement of Bipolar Disorder
Many scales available assessing depression (e.g., BDI, DASS, HAMDS).
Scales also available to measure mania (e.g., YMRS).
Few scales conceptualise both. General Behavior Inventory (GBI) provides
valid measure of depression and (hypo)mania.
Also allows separation of biphasic symptoms.
Measurement of RST Traits
BIS/BAS Scales (BBS) measure BAS and behavioural inhibition system (BIS).
Validated on Australian sample. Divide BAS into statistically-identified
subscales (Drive, Fun-Seeking, Reward Responsiveness).
Alternate measures (SPSRQ, GRAPES, AGQ) either more simplistic in structure, measure subtly different content, or are simply redundant.
Research Questions Do mood variability traits correlate with RST
traits? How is risky decision-making influenced by mood
variability and RST traits? Does mood variability impair cognitive flexibility,
and if so, does this occur generally or only during tasks that engage reward sensitivity processes?
Are individuals more or less likely to engage in riskier decision-making dependent on their mood state?
How is the effect of mood state modulated by underlying personality traits?
Series of Studies Study 1 (N = 760): Self-report trait investigation
examining the structure of mood variability and RST using exploratory and confirmatory factor analysis.
Study 2 (N = 118): Behavioural investigation examining performance on a range of cognitive-affective tasks assessing risky decision-making and set-shifting.
Study 3 (Positive n = 53, Negative n = 68): Mood induction experiment examining how state manipulations interact with underlying traits to influence performance on a risky decision-making task.
Study 1 Design
GBI BIS/BAS Scales
Hypomania and Biphasic Symptoms
Depression
BAS-RR
BAS-FS
BIS
BAS-D
Study 1 Results
Note. These results were not replicated in the smaller Study 2 sample.
Study 2 Design
WCST
BART
SS-IGT
GDT
Study 2 Results Systematic exploration at level of (i) bivariate
correlations, (ii) hierarchical regression controlling for affect, (iii) structural regression models testing for mediation.
No consistent pattern of correlation present across tasks at any level of analysis, despite task outcomes and self-report traits purporting to measure similar constructs.
This finding conflicts with previous research and the theory that BAS dysregulation is of key importance to phenomena characteristic of bipolar disorder.
Study 3 Design
Positive Mood Induction Group
Negative Mood Induction
Group
Neutral False Feedback
BART (Baseline Mood)
Positive False Feedback
BART (Positive Mood)
Neutral False Feedback
BART (Baseline Mood)
Negative False Feedback
BART (Negative Mood)
Study 3 Results Mood induction appeared to function as
expected. Although significant differences were found
between and within BART trials, these appeared to be artefacts of fatigue and baseline variance.
Underlying traits did not predict behaviour change on the BART.
Underlying traits did not predict mood induction susceptibility in a consistent manner.
Conclusions Despite the range of evidence linking BAS dysregulation
to bipolar disorder, this was not evident in the present study.
Rigorously tested observationally and experimentally across range of studies.
Potential explanations for lack of significance:- Possible that BAS is important to individual clinical
phenomenology but this is obscured at more general trait level.
- Possible that BAS dysregulation is only a significant influence upon clinically severe cases (implying a qualitative difference).
- Possible that what has been labelled as euthymic BAS dysregulation is in fact prodromal or residual symptom of manic or hypomanic state.
Thank-you for Listening! I hope that you enjoyed the
presentation. Does anyone have any questions?