In contrast to previous conceptions of bipolar disorder as an illness where cognitive impairments were limited to manic and depressed episodes, it has become clear that cognitive impairments are common in clinically stable bipolar patients.
Quetiapine has been reported to have beneficial cognitive effects in several randomized controlled trials in schizophrenia. It has not yet been studied in bipolar disorder, but promising results from the use of extended release quetiapine for the maintenance treatment of bipolar disorder suggests that its cognitive benefits could be detected. Moreover, quetiapine has been shown to have direct beneficial effects on performance-based measures of social competence in schizophrenia and to improve quality of life (QoL) in bipolar depression. We propose to study quetiapine augmentation of mood stabilizer monotherapy in clinically stable patients with bipolar disorder. This will be a randomized, placebo controlled trial, with attentional impairments as the primary outcome and other cognitive performance variables and measures of social and everyday living skills, as well as subjective QoL, as the secondary outcomes.
An additional possible benefit of quetiapine treatment, and one that is directly relevant to neuropsychological performance, is that of increased activity of cortical norepinephrine (NE). Thus, in studies of cognitive enhancement with quetiapine, examination of cortical NE neet occupancy will be of substantial interest.
General Background: This will be a three site study which will include Emory University (Coordinating site), Duke University, and University of Toronto. We choose to have three sites so that the difficult task of recruiting clinically stable patients with bipolar can be accomplished quickly and the study can be completed within a two-year time frame.
Subjects: We will recruit 100 patients for this study. Fifty percent of them will receive active treatment with quetiapine XR. All participants will meet diagnostic criteria for bipolar I and II disorder and have medical record-based evidence of at least one previous manic or mixed episode. They will be clinically stable, as evidence by meeting criteria for low scores on both the Young Mania Rating Scale (YMRS) and the Montgomery-Asberg Depression rating scale (MADRS). They will also be receiving therapy with mood stabilizers, either lithium or an approved mood stabilizing agent.
Visit Schedule: This is a 10 week study with a six-week active treatment protocol. All interested patients who meet study entry criteria will be screened for stability four and two weeks prior to the baseline assessment. Patients will also be re-assessed for stability at baseline. Patients who fail to meet entry criteria at baseline can come back for a second screening after 2 and 4 weeks.
Throughout treatment, medication adjustments will be limited to changes of less than 25% during this time period.
Assessments: Cognitive assessments will be performed at baseline, week 2 and week 6 of active treatment.
Clinical Assessments will be performed at screening and rescreening, baseline, weeks 2 and 6.
Biological Measures: Bloods for NE net occupancy will be drawn at baseline, week 2, and week 6. Serum levels of quetiapine at all three assessments will also be examined.
Cognitive Assessments:
We will focus our cognitive assessment on the types of cognitive impairments previously reported in bipolar disorder. Our focus will be on attention, episodic memory, processing speed, and working memory. This same instrumentation has proven able to detect sedation as well, so that we can use the results of our assessment to identify any potential adverse sedation effects.
