Previous research has suggested that cognitive impairments may predict recurrent psychotic episodes, but data on the association between specific cognitive deficits and relapse of psychosis over time are limited, wrote Tiffany J. Tao, MPhil, a PhD candidate at the University of Hong Kong, and colleagues.
In a naturalisticpublished in Psychiatry Research , the researchers recruited psychosis patients with full remission for a least 6 months from two outpatient psychiatric clinics. The study population included adults aged 18-55 years, with an average age of 29.2 years; 62% were women. Relapse, defined as a recurrence of psychotic symptoms measured by the Positive and Negative Syndrome Scale (PANSS) and the Clinical Global Impression Scale, was assessed monthly via phone interviews with the use of a smartphone app. Cognitive decline was based on working memory deterioration, assessed monthly via the Visual Patterns Test (VPT) and the Letter-Number Sequencing (LNS) test, respectively, for visual and verbal working memory.
Overall, 18 patients (16%) experienced a relapse at 1 year. One-third of these (six patients) required hospitalization, with a median hospital stay of 23 days.
In a multivariate analysis, independent and significant predictors of relapse were verbal working memory deterioration 2 months prior to relapse (P = .029), worse medication adherence (P = .018), and less resilience (P = .014) with odds ratios of 9.445, 0.051, and 0.769, respectively.
“Specifically, declines in verbal working memory were observed beginning at 2 months prior to the relapse episode in both the univariate and multivariate models after controlling for other significant predictors,” the researchers wrote in their discussion.
The mechanism of action for the association remains unclear, but cognitive impairment might reflect dopamine dysregulation or other processes in the prefrontal cortex that could contribute to psychotic relapse, they said.
Other factors include the associations between cognitive impairment and medication nonadherence, and the impact of cognitive impairment on a patient’s ability to manage the stresses of daily living that could trigger a psychotic relapse, they added.
Notably, the current study identified verbal working memory, but not visual working memory, as a predictor of relapse, which is important given the different neurobiological bases for visual and verbal tasks, the researchers wrote.
The study findings were limited by several factors including the inability to identify weaker predictors of relapse given the low relapse rate, and potential lack of generalizability to other less homogeneous populations, and the exclusion of patients with illicit drug use, the researchers noted.
However, the results were strengthened by the prospective measurements that prevented recall bias, and the inclusion of other objective predictors of relapse. The findings highlight the potential for early intervention to prevent relapse based on cognitive assessment, which can be measured objectively in the clinical setting or remotely from home using digital technology, they concluded.
The study received no outside funding. Ms. Tao had no financial conflicts to disclose.