Summary: A comprehensive scientific review identifies a major gap in knowledge about cognitive functioning when schizophrenia and personality disorders co-occur. Despite this dual diagnosis affecting a substantial portion of people with schizophrenia and being linked to poorer outcomes, only a handful of rigorous studies have examined cognition in this group. The review highlights the urgent need for improved cognitive assessment and tailored treatment strategies.
Cognition is one of the most important predictors of long-term recovery in schizophrenia. Yet individuals who have both schizophrenia and a personality disorder remain underrepresented in research, leaving clinicians with limited evidence to guide assessment and intervention. This gap makes it difficult to design effective, personalized treatments that address cognitive impairment and support functional recovery.
Key Facts
- High prevalence: About 40% of people diagnosed with schizophrenia also meet criteria for a personality disorder.
- Severe outcomes: The combination of schizophrenia and a personality disorder is associated with more severe psychotic symptoms, worse functioning, more frequent hospitalization, poorer adherence to treatment, and higher suicide risk.
- Research gap: Fewer than a dozen high-quality studies currently report on cognitive functioning specifically in people with this comorbidity.
Source: University of Montreal
A new scoping review led by researchers at Université de Montréal exposes a critical lack of robust evidence about cognitive profiles among people living with both schizophrenia and a personality disorder.
Published in Schizophrenia Research: Cognition, the review synthesized scientific literature spanning 24 years. The authors found that, despite the high prevalence of this comorbidity and its clear association with poorer prognosis, existing data are limited, heterogeneous, and sometimes conflicting.
“Our analysis reveals a substantial blind spot in current research,” said Anouck Chalut, Psy.D. in neuropsychology and lead author. “Very little is known about the specific cognitive deficits that accompany a personality disorder in people with schizophrenia.”
Under the direction of Professor Tania Lecomte—director of L’ESPOIR, a laboratory focused on improving care for people with severe mental disorders—the team screened hundreds of records but identified only ten studies that met rigorous inclusion criteria. These studies varied widely in methods, populations, diagnostic procedures and cognitive measures, which limited the ability to draw firm, generalizable conclusions.
Chalut noted that the scarcity and inconsistency of findings leave clinicians without clear guidance: “Because cognition is a decisive factor in functional recovery for people with schizophrenia, this gap in knowledge has real consequences for treatment planning and outcome prediction.”
Significant health challenges
Individuals with both schizophrenia and a personality disorder often face complex clinical needs. Research indicates they experience more severe psychotic episodes, greater functional impairment, lower medication adherence, higher rates of hospitalization and an increased risk of suicide. Despite these elevated risks, people with this dual diagnosis are frequently excluded from clinical trials or combined into broader schizophrenia samples, obscuring differences that might inform targeted interventions.
The review recommends systematic screening for personality disorder symptoms among people diagnosed with schizophrenia, and the routine use of standardized neuropsychological and social cognition assessments to better characterize cognitive profiles in this subgroup. Improved characterization would help clinicians tailor rehabilitation strategies and select appropriate therapies.
The authors point to cognitive remediation and other evidence-based cognitive interventions as promising approaches. Cognitive remediation focuses on improving impaired mental functions—such as memory, attention, processing speed and problem-solving—and teaches compensatory strategies to support everyday functioning. However, the review emphasizes that evidence for adapting these interventions specifically for people with comorbid personality disorders and schizophrenia is currently limited.
Key Questions Answered:
A: Approximately 40% of people diagnosed with schizophrenia also meet criteria for a personality disorder.
A: It is associated with more severe symptoms, reduced functioning, higher suicide risk, and poorer adherence to treatment, which together worsen prognosis.
A: Clear, consistent data on cognitive functioning—both general neuropsychological performance and social cognition—in people with this comorbidity.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full by the editorial team.
- Additional context and clarification were added by staff to summarize key clinical and research implications.
About this schizophrenia and personality disorders research news
Author: Julie Gazaille
Source: University of Montreal
Contact: Julie Gazaille – University of Montreal
Image: The image is credited to Neuroscience News
Original Research: Open access. “Cognitive deficits in individuals with comorbid personality disorder and schizophrenia: A scoping review” by Tania Lecomte et al., published in Schizophrenia Research: Cognition.
Abstract
Cognitive deficits in individuals with comorbid personality disorder and schizophrenia: A scoping review
Objective
Approximately 40% of people diagnosed with schizophrenia also meet diagnostic criteria for a personality disorder, a comorbidity that tends to predict a poorer course of illness. Given that cognitive functioning is currently the strongest predictor of recovery in schizophrenia, this review aimed to map and characterize cognitive profiles in individuals who have both schizophrenia and a personality disorder, using literature published over the past 24 years. The review asked whether cognitive deficits in the comorbid group differ from those observed in people diagnosed with schizophrenia alone, and sought to describe any distinguishing patterns.
Method
Studies were identified through searches of major scientific databases, with inclusion criteria requiring the use of neuropsychological or social cognition measures, validated diagnostic procedures to establish psychiatric diagnoses, participant samples that included individuals with both schizophrenia and a diagnosed personality disorder, and presentation of neuropsychological results specific to that comorbid group. Only studies that met these methodological standards were included in the synthesis.
Results
Ten studies met the inclusion criteria. Among them, six used clinical methods to establish personality disorder diagnoses, while five assessed personality disorder traits. The studies varied considerably in design, sample characteristics and cognitive measures, preventing meta-analytic pooling or definitive statistical comparisons across studies.
Discussion/conclusion
The review identified a relative concentration of studies addressing antisocial personality features, with far fewer investigations of other personality disorder types. Given the high comorbidity of personality disorders in schizophrenia and the crucial role of cognition in functional and social outcomes, the authors call for more focused research. They recommend routine screening for personality disorder symptoms in schizophrenia care, standardized cognitive and social cognition assessments, and studies testing adapted cognitive interventions—such as cognitive remediation—tailored to the needs of people with this comorbidity. Improving research and clinical practice in this area could inform personalized treatment plans and ultimately improve recovery trajectories for a vulnerable group that has been largely overlooked.