Mental imagery in bipolar disorder: A PRISMA-compliant systematic review of its characteristics, content and relation to emotion

Mental imagery is often described as “seeing with the mind's eye” as it refers to perceptual experiences of sensory information in the absence of external sensory input (Kosslyn, Ganis, & Thompson, 2001). Mental imagery is known to be strongly related to emotion and is used in the context of therapy for the treatment of mood disorders, in particular in Imagery-focused Cognitive Therapy. Due to the predominance of emotional dysfunction in bipolar disorder (BD), mental imagery may be helpful in providing a better characterization of the illness. This systematic review aimed at extracting data about mental images’ (a) clinical characteristics (frequency, vividness and likelihood), (b) contents and (c) relation to emotion in individuals with BD. Authors performed the systematic review following the PRISMA statement. Among the 81 articles screened, 55 were assessed for eligibility after the removal of duplicates. A total of 5 studies met inclusion criteria, and covered a total of 298 unique participants. Differences in the clinical characteristics of mental imagery were found in individuals with BD as compared to healthy controls. The contents of images in BD appeared to be related to individuals’ current preoccupations and seemed to push them to take action, with high associated emotional ratings. The level of evidence remains limited due to the designs of the included studies. Additional research is needed to characterize mental imagery during thymic phases of BD. Such studies may potentially identify markers of the transition from one thymic phase to the next.