A systematic review on neuropsychological function in bipolar disorders type I and II and subthreshold bipolar disorders—something to think about

Abstract

Neuropsychological dysfunction is a well-established finding in individuals with bipolar disorder type I (BP-I), even during euthymic periods; however, it is less clear whether this also pertains to bipolar disorder type II (BP-II) or those with subthreshold states (SBP; subthreshold bipolar disorder), such as bipolar not otherwise specified (BP-NOS). Herein, we compare the literature regarding neuropsychological performance in BP-II vs BP-I to determine the extent of relative impairment, and we present and review all related studies on cognition in SBP. After systematically searching PubMed, Medline, PsycINFO, and The Cochrane Library, we found 17 papers that comprise all the published studies relevant for this review. The areas that are consistently found to be impaired in BP are executive function, verbal memory, visual spatial working memory, and attention. More studies than not show no significant difference between BP-I and BP-II, particularly in euthymic samples. Preliminary evidence suggests that patients experiencing major depressive episodes who also meet criteria for SBP show similar profiles to BP-II; however, these results pertain only to a depressed sample. SBP were found to perform significantly better than both MDD and healthy controls in a euthymic sample. A consensus on mood state, patient selection, and neuropsychological testing needs to be agreed on for future research. Furthermore, no studies have used the most recent DSM-5 criteria for SBP; future studies should address this. Finally, the underlying bases of cognitive dysfunction in these diagnostic groups need to be further investigated. We suggest recommendations on all of the above current research challenges.

Executive functions and memory in bipolar disorders I and II: new insights from meta‐analytic results

“…The presence of differences in cognitive flexibility and inhibition between these participant groups has also been reported in previous meta-analyses (8,10). These observations support the idea that executive dysfunction is perhaps the most prevalent and severe cognitive impairment in BDII (65). Effect sizes for working memory, verbal fluency, and episodic memory between patients with BDII and control participants were numerically smaller but still significant.…”

Driving performance of euthymic outpatients with bipolar disorder undergoing real‐world pharmacotherapy

“…The BD group showed a small to moderate decrease in broad neurocognitive functions compared with the HCs, similar to previous studies. 6 To the best of our knowledge, this is the first study to elucidate the driving performance necessary for daily driving in patients with BD using a sufficient sample size. Several factors may have affected the car-following and roadtracking performance in the BD group.…”

“…Patients with bipolar disorder (BD) must receive maintenance therapy from the viewpoint of preventing recurrence, even if their symptoms subside, and clinicians should focus on patients' functional outcomes, such as school attendance, work performance, and independent living, with the aim of recovering social functions while continuing maintenance therapy. On the other hand, neurocognitive impairment [1][2][3][4][5][6] persists in patients with BD, even in the remission state, and is known to be strongly associated with daily functions. 7 Previous studies have shown that neurocognitive functions such as executive and attentional function consistently decrease in patients with BD.…”

Neuropsychologische Prädiktoren für den Erfolg beruflicher Wiedereingliederung

“…Auch wenn Patienten mit bipolar affektiven Störungen in Programmen zur beruflichen Rehabilitation unterrepräsentiert scheinen, liegen doch gesicherte Befunde zu kognitiven Beeinträchtigungen bei diesen Erkrankungen vor [29]. Auch hier treten Defizite in den Exekutivfunktionen, dem verbalen Gedächtnis, im visuell-räumlichen Gedächtnis sowie in der Aufmerksamkeit auf.…”