Schizophrenia Research Roundup: December 22, 2023


What is new in research on schizophrenia?

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science thodonal_AdobeStock

In this Research Roundup, we explore new studies on schizophrenia and its relationship to cat ownership, COVID-19 infection, comorbid substance use disorders, and more.

Exploring Connections Between Cat Ownership and Schizophrenia
This systematic review and meta-analysis investigated the relationship between cat ownership and schizophrenia-related disorders. The analysis revealed an association between broadly defined cat ownership and an increased likelihood of developing schizophrenia-related disorders, with an unadjusted pooled odds ratio of 2.35 and an adjusted estimate of 2.24.

“Our findings support an association between cat exposure and an increased risk of broadly defined schizophrenia-related disorders,” the investigators concluded. “However, the findings related to [psychotic-like experiences] (PLE) as an outcome are mixed. There is a need for more high-quality studies in this field.”


McGrath JJ, Lim CCW, Saha S. Cat ownership and schizophrenia-related disorders and psychotic-like experiences: a systematic review and meta-analysis. Schizophr Bull. 2023;sbad168.

Efficacy of Brexpiprazole in Patients With Schizophrenia and Comorbid SUDs
This study investigated the efficacy of the partial dopamine D2 receptor agonist brexpiprazole in the treatment of psychotic symptoms in patients with schizophrenia, comparing those with comorbid substance use disorders (SUD) and those without (non-SUD). Administering brexpiprazole for 6 months led to significant improvements in psychotic symptoms in both groups, indicating that SUD comorbidity did not hinder the treatment’s effectiveness. Brexpiprazole was also associated with a reduction in substance craving in the SUD group over the study period.

“Treatment with brexpiprazole for 6 months improved psychotic symptoms in patients with schizophrenia, independently from whether they belonged to the SUD or the non-SUD group; hence, SUD comorbidity did not confer treatment resistance to brexpiprazole,” the investigators concluded.


Lombardozzi G, Trovini G, Amici E, et al. Brexpiprazole in patients with schizophrenia with or without substance use disorder: an observational studyFront Psychiatry. 2023;14:1321233.

COVID-19 Infection and New-Onset Schizophrenia Spectrum and Psychotic Disorders
This study, analyzing data from 19,344,698 patients, investigated the long-term psychiatric effects of COVID-19, with a focus on schizophrenia spectrum and psychotic disorders (SSPD). Utilizing acute respiratory distress syndrome (ARDS) and COVID-19 lab-negative cohorts as controls, the investigators found that COVID-19-positive patients consistently exhibited a higher hazard ratio for new-onset SSPD across various time intervals compared with the control groups. Younger individuals also showed an elevated risk of SSPD after contracting COVID-19.

“These results, aligned with the known neurotropism of SARS-CoV-2 and earlier studies, accentuate the need for vigilant psychiatric assessment and support in the era of long COVID, especially among younger populations,” the investigators concluded.


Rahman A, Russell M, Zheng W, et al. SARS-CoV-2 infection is associated with an increase in new diagnoses of schizophrenia spectrum and psychotic disorder: a study using the US National COVID Cohort Collaborative (N3C). Preprint. medRxiv. 2023;2023.12.05.23299473.

Note: This Research Roundup was prepared with the assistance of ChatGPT.

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