Comprehensive Summary
This study intended to identify and describe exposotypes in psychotic disorders and controls by utilizing an unsupervised machine learning clustering approach. By recruiting participants as part of the B-SNIP2 study from 5 different states, the researchers were able to recruit an adequate number of control participants. Clustering was performed using clValid v0.7 in R, and these clusters were validated using two approaches–Results-based and Method-based–to determine accuracy of results. Four exposotypes were identified - ET1 (high childhood trauma and substance use), ET2 (high childhood trauma), ET3 (high substance use), and ET4 (low exposure). It was found that the exposotypes differed in age ranges, with people from ET1 and ET2 having a tendency to be 2-3 years older than their ET3 and ET4 counterparts. ET1 and ET2 also demonstrated the highest scores on the PANSS-Positive and PASS-General Psychopathology subscales compared to ET3 and ET4. ET1 and ET2 showed significantly higher levels of anxiety and impulsivity than ET3, and showed significantly higher levels of depression than ET4. The results displayed by ET1 were as expected as previous literature and the researchers themselves had studied the interactions between ET1 and psychotic symptoms. Interestingly, E2 individuals did not showcase any significant cognitive or functional impairments compared to their counterparts, suggesting that there is a potential disconnect between symptom severity and cognitive/functional outcomes.
Outcomes and Implications
This research is important as psychiatry is a field that often doesn’t take etiological approaches to treatment into account compared to other fields of medicine, despite a general awareness that etiological factors such as childhood trauma, substance use, and socioeconomic status have significant impact on psychotic disorder symptoms and their severity. This work might encourage psychiatrists to start varying their methodological approaches to research, rather than only using phenotypic and biotype approaches. Also, patient treatment could be improved with specific, targeted intervention for those in the different subgroups presented in this article. In the future, research could examine a wider range of environmental exposures, and explore the relationships between exposotypes and other psychiatric outcome measures.