A recent study from Université de Montréal has found significant gaps in knowledge regarding the cognitive profiles of individuals diagnosed with both schizophrenia and a personality disorder. The research, published in Schizophrenia Research: Cognition, involved a comprehensive review of scientific literature spanning 24 years.
The team, led by psychology professor Tania Lecomte, director of L'ESPOIR laboratory at UdeM's Department of Psychology, reviewed hundreds of articles but identified only 10 that met their standards for scientific rigor. According to the study, about 40 percent of people diagnosed with schizophrenia also have a personality disorder. Despite this high prevalence and its association with negative outcomes such as more severe symptoms and higher risk factors, data on this dual diagnosis remain limited and fragmented.
"We found that the existing research is limited, fragmentary and sometimes contradictory, leaving clinicians with few clear guidelines," noted Chalut. This gap is consequential because cognition is the strongest predictor of recovery for individuals living with schizophrenia, she said.
Individuals facing both conditions often experience more severe psychotic symptoms, greater functional impairment, reduced medication compliance, increased hospitalization rates, and a higher risk of suicide. However, these patients are frequently excluded from clinical studies or grouped solely under schizophrenia without accounting for the additional complexity introduced by personality disorders.
"Our findings underscore the need to improve our understanding of these individuals and focus on their cognitive profiles to support functional recovery, given that cognition plays a decisive role in that process," said Chalut.
The researchers recommend systematic screening for personality disorder symptoms among those living with schizophrenia and advocate for standardized tools to better characterize cognitive profiles within this group. They emphasize the necessity for further research into tailoring treatments and therapies to meet the specific needs of people affected by both conditions.
One potential approach highlighted is cognitive remediation therapy. This method aims to reduce cognitive deficits by strengthening mental abilities such as memory, attention, and problem-solving—areas often impaired in those with dual diagnoses.
