Mental imagery in bipolar affective disorder versus unipolar depression: investigating cognitions at times of 'positive' mood.

BACKGROUND: Compared to unipolar depression (UD), depressed mood in bipolar disorder (BD) has been associated with amplified negative mental imagery of the future ('flashforwards'). However, imagery characteristics during positive mood remain poorly explored. We hypothesise first, that unlike UD patients, the most significant positive images of BD patients will be 'flashforwards' (rather than past memories). Second, that BD patients will experience more frequent (and more 'powerful') positive imagery as compared to verbal thoughts and third, that behavioural activation scores will be predicted by imagery variables in the BD group. METHODS: BD (n=26) and UD (n=26) patients completed clinical and trait imagery measures followed by an Imagery Interview and a measure of behavioural activation. RESULTS: Compared to UD, BD patients reported more 'flashforwards' compared to past memories and rated their 'flashforwards' as more vivid, exciting and pleasurable. Only the BD group found positive imagery more 'powerful', (preoccupying, 'real' and compelling) as compared to verbal thoughts. Imagery-associated pleasure predicted levels of drive and reward responsiveness in the BD group. LIMITATIONS: A limitation in the study was the retrospective design. Moreover pathological and non-pathological periods of "positive" mood were not distinguished in the BD sample. CONCLUSIONS: This study reveals BD patients experience positive 'flashforward' imagery in positive mood, with more intense qualities than UD patients. This could contribute to the amplification of emotional states and goal directed behaviour leading into mania, and differentiate BD from UD.