UK researchers have found that individuals with bipolar disorder (BD) respond differently to positive mood induction than healthy individuals.

They hope that knowing how patients with bipolar disorder respond to positive mood induction could enable clinicians to help BD patients better regulate their mood. Guidance during cognitive behavioral therapy could teach patients to become aware of the automatic changes to emotional processing that occur during the early stages of mood elevation.

In the present study, Anne Farmer (Institute of Psychiatry, London) and co-authors investigated the effect of positive mood induction on emotional processing in 15 euthymic individuals with BD and 19 gender- and age-matched healthy controls, using the Affective Go/No-go test (AGNG) and the Cambridge Gamble task (CGT).

The researchers manipulated mood using a feedback paradigm, which was found to be more effective than more widely used techniques. Mood induction using the “Go” task significantly elevated mood in both groups, and this effect lasted until after completion of the AGNG and CGT.

Patients in the BD group responded more slowly on the CGT when presented with more difficult decisions (when the probability of being correct was lower) than controls, and this effect remained significant after adjusting for age. However, no differences were seen between groups in the extent to which participants altered their betting behavior as a function of risk, or in the quality of decision making.

The authors say that the slow responses made in the face of a difficult decision reflect the BD patients’ “difficulty in overcoming the inclination to engage in behavior with a high potential for negative consequences, which may have been elicited by the mood induction.”

Furthermore, bipolar patients showed a positive emotional bias on the AGNG, as they made significantly more inappropriate responses to positive distractor words than negative distractor words following mood induction, whereas controls did not.

“These data suggest that individuals with BD and healthy controls respond to positive mood induction in a qualitatively different manner,” write the authors in the journal Psychological Medicine.

Farmer et al say that positive mood induction in euthymic individuals with BD “is sufficient to re-establish the biases in information processing and disruptions to decision-making behavior that occur in the manic state.”

MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a part of Springer Science+Business Media. © Current Medicine Group Ltd; 2009

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