Abstract

Bipolar disorder is associated with cognitive deficits, which persist across mood states and affect functional outcomes. This article provides an overview of recent progress in measuring cognition in bipolar disorder and its implications for both research and clinical practice. The authors summarize work conducted over the past decade that has helped guide researchers and clinicians in the appropriate measurement of cognitive functioning in bipolar disorder, the design of research studies targeting this domain for treatment, and the implementation of screening and psychoeducational tools in the clinic. Much of this work was conducted by the International Society for Bipolar Disorders Targeting Cognition Task Force. Here, the authors also highlight the need for clinicians to be informed about this aspect of illness and to be equipped with the necessary information to assess, track, and intervene on cognitive problems when appropriate. Finally, the article identifies gaps in the literature and suggests potential future directions for research in this area.

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The cognitive deficits observed in bipolar disorder, in domains such as verbal learning, attention, and executive function (1), are qualitatively similar to those reported in schizophrenia, although less severe (2–4). It is important to note that the deficits in cognitive functioning, in areas such as attention, processing speed, explicit memory, and several aspects of executive function, persist even when patients are affectively stable (5–8) and are associated with poor quality of life (QoL) (9), disability, and an incomplete functional recovery (2, 9–17). Meta-analytic evidence shows that deficits in memory and executive function affect occupational outcomes in bipolar disorder even more than residual mood symptoms do (17, 18). Research over the past decade has described substantial heterogeneity (13) in the cognitive profiles observed among individuals diagnosed as having bipolar disorder, with 12%–40% displaying global cognitive deficits across multiple domains (i.e., verbal memory, attention, executive function, and psychomotor speed), 29%–40% displaying selective impairment in attention and psychomotor speed, and 32%–48% being relatively cognitively intact compared with healthy age‐matched individuals (13, 19–22).

The early identification of subgroups of patients with bipolar disorder who experience significant cognitive impairment, or whose course may be marked by cognitive decline, is a critical first step if intervention and prevention strategies are to succeed in promoting a full recovery (17). Clinical remission is no longer a sufficient treatment goal. Understandably, patients want to achieve functional recovery and optimize QoL; as such, this should be a key goal for clinicians who treat these patients (23). Given the prevalence and adverse psychosocial impact of cognitive dysfunction in the illness, clinicians will want to be informed about this aspect of illness and be armed with the information that they need to assess, track, and intervene on cognitive problems when appropriate. In this article, we attempt to summarize the recent progress in this area, with an eye toward a clinician audience. Here, we highlight much of the excellent work carried out by the International Society for Bipolar Disorders (ISBD) Targeting Cognition Task Force over the past decade, which has helped to guide researchers and clinicians alike in the appropriate measurement of cognitive functioning in bipolar disorder, the ideal design of research studies targeting this domain for treatment, and the implementation of screening and psychoeducational tools in the clinic. Next, we briefly identify gaps in the literature and discuss potential future directions.

Measurement of Cognition in Bipolar Disorder

In the Clinic

Given the strong relationship between cognitive deficits and functional outcomes in bipolar disorder, the clinical relevance is clear, yet cognition is rarely assessed in patients with bipolar disorder in regular clinical practice. . . .