Key Publications
For a list of all publications, please see Dr. Bowie’s CV or Google Scholar Page.
Click on the image to link to the full publication online.
This paper was the first to demonstrate how neurocognitive abilities were mediated by functional competence (what one is currently able to do) in predicting real world performance (what one actually does). We also showed that this path from neurocognition to everyday functioning was stronger (independently or as mediated by functional competence) than symptoms of psychosis like hallucinations and delusions.
In this randomized controlled trial, we showed that the effects of cognitive remediation on functioning were limited when they were not supplemented by an additional therapy that built functional competence skills. This study builds from the correlational findings of the 2008 paper above in that we tested whether this mediation effect could explain limited transfer of cognitive gains to real world outcomes. This treatment trial was also a bridge to the development of our flagship treatment, Action-Based Cognitive Remediation, as it showed us options for building new treatment procedures into cognitive remediation that could facilitate improved everyday outcomes.
This paper was the first to examine cognitive remediation for treatment-resistant depression and the first to show that the amount of improvement in cognition and was associated with the amount of at-home supplemental cognitive training that participants did outside of therapy sessions.
Dr. Bowie led a team of international experts to develop consensus guidelines on the core techniques used in cognitive remediation.
One of the challenges with enrolling potential participants in cognitive remediation, like other therapies, is that the treatment can seem like a big commitment. In this study, we showed that even a relatively brief version of cognitive remediation that could be continued at home can produce positive effects. We also showed that depending on the modality of treatment – top-down versus bottom-up processes – specific types of treatment effects could be expected. Targeting executive functioning produced larger effects on everyday outcomes than perceptual training.
Cognitive issues are difficult to assess, due to the nature of the testing environment, variability across tests and within a person’s own range of cognitive skills, and with uncertainty about whether performance declines are associated with the illness onset or a consequence of the illness. To address some of these questions, we examined cognitive deficits in people with Major Depressive Disorder who enrolled in cognitive remediation treatment. Surprisingly, only about 1/4 of the sample demonstrated performance that would be considered in the impaired range compared to the general population. However, when we looked at within-person performance, by comparing current cognitive functioning with estimates of overall cognitive ability prior to illness onset, we saw nearly 2/3 of the sample would be considered to have cognitive deficits because they were underperforming relative to their potential. When we looked at how these two ways of defining cognition (normative – compared to the general population and idiographic – your current vs pre-illness ability) had different relationships with functioning measures. Specifically, cognitive ability at present is strongly associated with functional competence, but the degree to which cognition has declined is associated with your beliefs about how you are functioning. From this study, we can think differently about how to consider whether someone might be a candidate for cognitive remediation and how the beliefs those with depression have their ability might be skewed by how much cognitive loss they have sustained.
For her MSc thesis, Tanya Tran developed a new paradigm to assess cognitive effort avoidance. With this task, in a paradigm similar to the commonly used EEFFRT task by Treadway, examined how those with depression reacted to choices to seek more reward for an effortful task or a lower reward for an easy task. The traditional EEFFRT task showed relationships with the symptom of anhedonia, but only the cognitive effort task showed relationships with everyday functioning. The cognitive effort task also mediated the relationship between cognitive ability and everyday functioning, suggesting that those with depression might be at risk for more challenges functioning in daily life because of their cognitive deficits and a preference to avoid tasks that are more cognitively taxing.
In the CPD lab, we often do work that bridges our experimental findings with what we hope will eventually be a part of treatment or even new types of treatment. In an example of this proof-of-principle work, Stephanie Woolridge started a project as an undergraduate honour’s thesis student and finished it during her MSc. We created a new paradigm, in collaboration with Geoff Harrison from the Attention Lab at Queen’s, in which data from eye tracking measurements manipulated the images on a computer screen where those with depression were examining either positive or negative social information. In the group randomized to receive this training, we were able to modify attention bias away from negative stimuli and found that the results generalized to a test of emotional verbal memory.
This paper reports on the initial pilot study of our treatment for internalized (self-) stigma in psychosis: BOOST. We are currently conducting a large follow-up trial of BOOST at multiple sites. Part of our aims in the CPD lab are to make sure that the initial results that we find are replicated by us in larger trials and independently by others, so they can be disseminated to clinicians for use in daily life. We have provided the BOOST manual and materials to clinicians in Canada, the U.S., Korea, and Spain.
Some of our work is focused on using experimental studies to better understand stigma and social exclusion. In this study, as part of his MSc thesis, Mike Best found that when participants from the community listen to speech that contains word use common in schizophrenia (sometimes called disorganized speech), an event-related potential (indicating a change in neural resources) called the N400 occurs. This neural activity typically manifests when a person hears something unexpected (we might think of it as a “wait…what?” effect). Participants were randomly assigned to be told they were listening to a person with schizophrenia or just to a speaker, when in fact both groups were listening to the same actor. The group told they were listening to the speaker reliably showed the N400 effect, but the group told they were listening to someone with schizophrenia did not. This might suggest that neural resources that are meant to alert the listener to try to make sense of unusual behaviour are suppressed when the listener thinks the speaker has schizophrenia.
In this study, part of Chelsea Wood-Ross’ undergraduate thesis, we were able to show that those with depression are able to perform on cognitive training tasks at a comparable level to the general population, but that they perceive their performance as worse. EEG measurement also suggested a disengagement from the task as difficulty increased. Implications for therapy were also found – those with depression were more likely to indicate that they would like to lower the task difficulty as the task became harder, suggesting that in a cognitive training environment, people with depression might self-select a cognitive ecosystem that is less enriching. We can extend this to consider whether therapists can play a key role in ensuring that those with depression maintain a healthy cognitive ecosystem to promote cognitive health. In fact, that is precisely what we do with Action-Based Cognitive Remediation!
Dr. Bowie and Dr. Medalia edited this book on procedures that can be helpful to improve functioning when using cognitive remediation.