Neurocognitive Training in Patients with Bipolar Disorders: Current Status and Perspectives

The main objective here is to study the current status of research in cognitive training/rehabilitation in patients with BD. The second aim is to discuss the suitability of current cognitive training programs in SCH for use in BD. Finally, some recommendations to increase the effectiveness of cognitive training for BD patients will be outlined. Papers were identified through a comprehensive literature search restricted to human studies but without language restrictions. Electronic searches covering the period from 2000 to March 2011 were performed in Medline and PsycINFO databases. To start with, a search was performed in Medline using the search string: ‘bipolar disorder’ AND ‘cognitive remediation’ OR ‘neurocognitive remediation’ OR ‘neuropsychological remediation’ OR ‘cognitive training’ OR ‘neurocognitive training’ OR ‘neuropsychological training’ OR ‘cognitive rehabilitation’ OR ‘neurocognitive rehabilitation’ OR ‘neuropsychological rehabilitation’. This resulted initially in 13 hits but 1 was discarded because it did not refer to BD, leaving 12 references. Next we performed the same search in PsycINFO databases using the identical search string. This returned 10 hits but only 2 were new as 8 had already been found in our initial search, so our final result was a total of 14 references. Additional searches in other databases (EBSCO Host, ProQuest) did not modify results. Electronic searches identified 14 references, and 2 more [19, 20] were found in their reference lists, therefore 16 potentially relevant articles were included. Eleven of them actually only emphasize the potential relevance that cognitive training might have, pointing out that it may become a very important part of treatment in BD. However, those papers did not involve any cognitive training program. Interesting observations from these studies are: (1) research on SCH could serve to guide studies needed in BD [21, 22] ; (2) a more comprehensive approach to BD treatment with cognitive remediation therapy is necessary [23, 24] ; (3) there is a need for formal assessment of cognition by using standard cognitive test batteries [25, 26] ; (4) improvement in cognition should translate into better social and functional outcome [27–31] . Out of the 5 remaining papers, 4 are examples of cognitive training with heterogeneous samples including some patients with BD together with patients with other diagnoses (with psychotic disorders and other mood disorders) [19, 20, 32, 33] . However, these studies have additional methodological problems, such as small samples and the lack of a control group. Moreover, these empirical studies are not considering important information arising from areas such as cognitive remediation in SCH or patients with brain injury [26] . Finally, the only empirical study with a homogeneous sample of BD patients suggested that improvements in occupational and psychosocial functioning in individuals with BD may be achieved by targeting residual depressive symptoms and cognitive impairment [34] . However, beneficial effects of remediation on cognitive functioning may be confused with those on mood state. Overall, It has been estimated that between 30 and 60% of bipolar disorder (BD) patients have psychosocial dysfunctions, as measured by impairment in occupational and social functioning [1] . Even those who achieve full clinical remission have difficulty in making a complete functional recovery [2–7] . In a recent review, the functional outcome of BD has been associated with several demographic, clinical, pharmacological, psychological and social variables [8, 9] . Cognitive dysfunction is included in this set of variables. Approximately 60% of BD patients are cognitively impaired at a level deemed to be clinically relevant, even during periods of clinical remission [10] . Recent longitudinal reports [10–12] indicated that cognitive disturbances might predict a poorer psychosocial adjustment in the longer term. Specifically, baseline deficits in fluency and attention/psychomotor speed [13] , and in verbal memory, executive and attentional functions were independent predictors of functional recovery 1 year later [10] . A global index of cognition was more predictive of functional outcome than clinical factors in both schizophrenia and BD [11] . Similarly, other studies also reported that subthreshold depressive symptoms and verbal memory problems explained 36% of the variance in functioning at the 4-year follow-up [14] . This data highlights the importance of using suitable interventions to improve neurocognitive dysfunctions in patients with BD [12, 15] . Cognitive training aims to improve neurocognitive abilities such as memory, learning, attention and executive functioning [16] . Compared to schizophrenia (SCH), BD has been historically regarded as a disease with a better prognosis and outcome, so psychosocial outcomes in patients with BD have generally received less attention than those of patients with SCH [17, 18] . Received: May 3, 2011 Accepted after revision: December 11, 2011 Published online: June 1, 2012