Clinical Determinants of the Discrepancy Between Objective and Subjective Cognition in the Versailles FACE-BD Cohort

Metacognitive abilities have been scarcely investigated in bipolar disorders, with inconsistent results. This may appear somewhat surprising, as metacognitive training is a very promising intervention aiming at improving psychosocial functioning in bipolar disorders. One way to investigate metacognition is to address the discrepancy between objectively measured cognition (through neuropsychological testing) and subjective cognition (through self-reported questionnaire investigating one's perception of cognitive functioning).

Objective and subjective cognition are two fundamental determinants of functioning in bipolar disorder. Objectively-measured cognition is directly associated with performance-based functional capacity but not with self-reported or interview-based functional capacity. In contrast, subjectively-measured cognition is associated with self-reported and interview-based functional capacity, but not performance-based functional capacity.

Associations between subjective cognitive functioning and neuropsychological performances are usually weak, with a moderating effect of manic and depressive symptoms. Manic symptoms are associated with a decrease in cognitive complains, whereas depressive symptoms are associated with an increase in cognitive complaints. Predictors of the discrepancy between objective and subjective cognition in bipolar disorder are still weakly understood. One study reported that the subjective overestimation of cognitive dysfunctioning was positively predicted by more subsyndromal depressive and manic symptoms, hospitalizations, and BD type II. This study also reported that the subjective overestimation of cognitive dysfunctioning was associated with greater socio-occupational difficulties, more perceived stress, and lower quality of life.

However, these previous studies had relatively limited sample sizes (below 150). They also ignored other potential predictors of the discrepancy between objective and subjective cognitions such as psychotic features, impulsiveness, and childhood trauma. Moreover, they also ignored whether this discrepancy was associated with medication adherence.

The present study intends to explore the predictors of the discrepancy between objective and subjective cognition in bipolar disorder in a cross-sectional sample of 387 stable outpatients with bipolar disorders (type 1, type 2, not otherwise specified). All participants were included in the Versailles FACE-BD Cohort and were recruited via the Versailles FondaMental Center of expertise for Bipolar Disorders. BD was diagnosed based on the structured clinical interview that assesses DSM-IV-TR criteria.

Objective cognition was measured with a battery of cognitive tests. Experienced neuropsychologists administered the tests in a fixed order that was the same for every center. Testing lasted a total of 120 min, including 5 to 10-min breaks. The standardized test battery complied with the recommendations issued by the International Society for Bipolar Disorders. It included 11 tests and evaluated the following five cognitive domains:

• processing speed, using the digit symbol coding and symbol search subtests from the Wechsler Adult Intelligence Scale (WAIS) version III, the Trail Making Test (TMT) part A, and the word and the color conditions of the Stroop test
• attention, using the Conners' Continuous Performance Test II (omissions and commissions)
• executive functions, using the colour/word condition of the Stroop test, the TMT part B and verbal fluency (semantic and phonemic conditions)
• verbal memory, using the California Verbal Learning Test (CVLT) immediate recall, short and long delay free recall, and total recognition
• working memory, using the WAIS-III digit span (sum of forward and backward conditions) and the spatial span (forward and backward conditions) subtest from the Wechsler Memory Scale version III

Subjective cognition was measured with item 10 of the Quick Inventory of Depressive Symptomatology-Self-Report-16.

This item focuses over the past 7 days and investigates "Concentration/decision-making:

• 0 There was no change in my usual ability to concentrate or make decisions.
• 1 I occasionally felt indecisive or found that my attention wandered.
• 2 Most of the time, I found it hard to focus or to make decisions.
• 3 I couldn't concentrate well enough to read or I couldn't make even minor decisions"

Predictors of the discrepancy between objective and subjective cognition were:

• type of bipolar disorder
• psychotic features
• age at onset; number of previous mixed, hypomanic, manic, and major depressive episodes; total duration of hospitalizations
• severity of the bipolar disorder with the Clinical Global Impression-Severity
• lithium carbonate, anticonvulsants, antipsychotics, antidepressants, or anxiolytics at the time of testing
• hetero-evaluation of depression with the Montgomery Åsberg Depression Rating Scale
• hetero-evaluation of mania with the Young Mania Rating Scale
• auto-evaluation of the state of anxiety with the state subscale of the State-Trait Anxiety Inventory, form Y-A
• impulsiveness with the Barratt Impulsiveness Scale
• childhood trauma with the Childhood Trauma Questionnaire

The variable predicted by the discrepancy between objective and subjective cognition were:

• the global functioning with the Global Assessment of Functioning scale
• psychosocial functioning in everyday life was assessed with the Functioning Assessment Short Test
• medication adherence with the MEDICATION ADHERENCE RATING SCALE
• quality of life with the EQ-5D

Inclusion criteria

• bipolar disorder according to DSM IV-R (structured clinical interview)

Exclusion criteria

• substance-related disorders in the previous month
• electroconvulsive therapy in the past year
• substantial neurological disorder