Increased Prolactin Levels Are Associated with Impaired Processing Speed in Subjects with Early Psychosis

Abstract

Hyperprolactinaemia, a common side effect of some antipsychotic drugs, is also present in drug-naïve psychotic patients and subjects at risk for psychosis. Recent studies in non-psychiatric populations suggest that increased prolactin may have negative effects on cognition. The aim of our study was to explore whether high plasma prolactin levels are associated with poorer cognitive functioning in subjects with early psychoses. We studied 107 participants: 29 healthy subjects and 78 subjects with an early psychosis (55 psychotic disorders with <3 years of illness, 23 high-risk subjects). Cognitive assessment was performed with the MATRICS Cognitive Consensus Cognitive Battery, and prolactin levels were determined as well as total cortisol levels in plasma. Psychopathological status was assessed and the use of psychopharmacological treatments (antipsychotics, antidepressants, benzodiazepines) recorded. Prolactin levels were negatively associated with cognitive performance in processing speed, in patients with a psychotic disorder and high-risk subjects. In the latter group, increased prolactin levels were also associated with impaired reasoning and problem solving and poorer general cognition. In a multiple linear regression analysis conducted in both high-risk and psychotic patients, controlling for potential confounders, prolactin and benzodiazepines were independently related to poorer cognitive performance in the speed of processing domain. A mediation analysis showed that both prolactin and benzodiazepine treatment act as mediators of the relationship between risperidone/paliperidone treatment and speed of processing. These results suggest that increased prolactin levels are associated with impaired processing speed in early psychosis. If these results are confirmed in future studies, strategies targeting reduction of prolactin levels may improve cognition in this population.

Association between prolactin serum levels and cognitive function in chronic schizophrenia patients

“…However, a similar result to our findings is reported by Montalvo et al (2014). In this study the patients with brief evolution of psychosis displayed a lower cognitive performance associated with the effect of prolactin, especially in men.…”

“…With regard to cognitive symptoms, studies with high risk for psychosis individuals show a negative correlation between prolactin levels and performance of reasoning, problem solving, and general cognition tasks (Labad, 2019). Moreover, Montalvo et al (2014) reported a negative correlation between prolactin levels and processing speed tests performance in patients with first episode psychosis. Finally, Yao et al (2018) described a significant negative correlation between verbal memory and cognitive flexibility performance and hyperprolactinemia in women with schizophrenia.…”

Daytime somnolence as an early sign of cognitive decline in a community‐based study of older people

“…It has been shown that circadian rhythms control sleep and biological processes including cell regeneration, core body temperature variations, and hormone metabolism (Buysse et al ., 2005; Sharma and Kavuru, 2010). There is also evidence that changes in the metabolism, especially disorders of the thyroid function, may be associated with cognitive decline (Smith et al ., 2002) and specifically decrease in speed of processing (Montalvo et al ., 2014; Smith et al ., 2015). Furthermore, changes in the thyroid, especially hypothyroidism, is considered a reversible cause of secondary dementia in older adults (Horvath et al ., 1989; Cummings, 1992).…”

The search for new biomarkers for cognition in schizophrenia

“…Nevertheless, during the last few years, with increased research into cognition as a nuclear dimension of serious mental disorders (schizophrenia and related psychotic disorders, bipolar disorder), various studies have evaluated the function of prolactin in the cognition spectrum. One study of patients with early psychosis (less than three years since the first signs of symptoms) showed that elevated levels of prolactin were associated with deficits in processing speed independent of the use of antipsychotic drugs ( Montalvo et al, 2014 ). There is considerable controversy surrounding these results, however, because another study of cognition in male patients with schizophrenia demonstrated that prolactin did not interfere with the link between sex steroids, such as testosterone, and cognitive function ( Moore et al, 2013 ).…”