Research

Individuals affected by psychosis spectrum disorders (such as schizophrenia, schizoaffective disorder, bipolar disorder) experience more negative affect (such as sadness, anxiety, distress) more than those not affected by psychopathology. Our ongoing project aims to understand what underlies this stress-vulnerability to negative affect in psychosis spectrum disorders using electroencephalogram (EEG), laboratory interviews and questionnaires, ecological momentary assessment (EMA), and statistical modeling.

Relevant manuscripts:

• Bornheimer, L. A., Martz, M. E., Suzuki, T., Tso, I. F., Burton, C. Z., Li Verdugo, J., Grove, T., Heitzeg, M. M., & Taylor, S. F. (in press). Affective dysregulation precedes emergence of psychosis-like experiences in a community sample of young adults. Schizophrenia Bulletin. https://doi.org/10.1093/schbul/sbac015

• Kline, C., Suzuki, T., Sommonite, M., & Taylor, S. F. (In press). Catatonia is Associated with Higher Rates of Negative Affect amongst Patients with Schizophrenia and Schizoaffective Disorder. Schizophrenia Research.

EEG records electrical current emitted from brain activities at the scalp. It is a relatively cheap and well-tolerated method to measure brain activities that provides a unique perspective at the milliseconds precision. Researchers have used EEG to understand many forms of cognitive functioning and to understand brain activities that might underlie various forms of psychopathology. Our research also investigates the relations of EEG activities to personality and psychopathology and also their properties (e.g., in emotional and social contexts, psychometrics). We quantify EEG as event-related potentials (ERPs) as well as oscillatory activities using time-frequency decomposition.

Relevant manuscripts:

• Suzuki, T., Gu, P., Grove, T., Hammond, T., Collins, K., Pamidighantam, P., Arnold, P., Taylor, S., Liu, Y., Gehring, W., Hanna, G., & Tso., I. (2022). Abnormally enhanced midfrontal theta-band activity during response monitoring in children with obsessive-compulsive disorder. Biological Psychiatry. https://doi.org/10.1016/j.biopsych.2022.10.020

• Menkes, M., Andrews, C., Suzuki, T., Chun, J., O'Donnell, L. A., Grove, T. B., Deng, W., McInnis, M. G., Deldin, P. J., Tso, I. F. (2022). Event-related potential correlates of affective response inhibition in bipolar I disorder: Comparison with schizophrenia. Journal of Affective Disorders, 309, 131-140. https://doi.org/10.1016/j.jad.2022.04.118

• Suzuki, T., Ait Oumeziane, B., Novak, K., Samuel, D. B., & Foti, D. (2020). Error-monitoring across social and affective processing contexts. International Journal of Psychophysiology, 150, 37–49. https://doi.org/10.1016/j.ijpsycho.2020.01.009

• Suzuki, T., Novak, K. D., Oumeziane, B. A., Foti, D., & Samuel, D. B. (2020). The hierarchical structure of error-related negativities elicited from affective and social stimuli and their relations to personality traits. Personality Neuroscience, 3. https://doi.org/10.1017/pen.2020.15

The traditionally-defined 10 categorical PDs have been known for high co-occurence (diagnosis of multiple disorders) and hetereogenetiy (different symptoms across people even with the "same" disorder), among others. Recognizing this issue, the DSM-5, published in 2013, proposed a new transdiagnostic dimensional model called "the Alternative DSM-5 Model for Personality Disorders (AMPD)". However, this model was not included in the official diagnostic section (Section II), partly due to lack of research and knowledge on this new model. For decades, the Five-Factor Model (FFM) of general personality has also been investigated as a foundation for a transdiagnostic dimensional framework to understand PDs. The FFM is the most researched personality model with a rich literature. Therefore, linking the AMPD to FFM would facilitate and expedite our understanding of this new model. Our work has demonstrated that four of the five AMPD and FFM domains are essentially the same constructs, while the psychoticism vs. openness to experience pair to be the only exception.

Relevant manuscripts:

• Suzuki, T., Samuel, D. B., Pahlen, S., & Krueger, R. F. (2015). DSM-5 alternative personality disorder model traits are maladaptive extreme variants within the five-factor model: An item-response theory analysis. Journal of Abnormal Psychology, 124, 343-354. https://doi.org/10.1037/abn0000035

• Suzuki, T., Griffin, S. A., & Samuel, D. B. (2017). Capturing the DSM-5 alternative personality disorder model traits in the five-factor model’s nomological net. Journal of Personality, 85, 220-231. https://doi.org/10.1111/jopy.12235

• Suzuki, T., South, S. C., Samuel, D. B., Wright, A. G. C., Yalch, M. M., Hopwood, C. J., & Thomas, K. M. (2019). Measurement invariance of the DSM–5 Section III pathological personality trait model across sex. Personality Disorders: Theory, Research, and Treatment, 10, 114–122. https://doi.org/10.1037/per0000291