The normothymic phase in bipolar disorders is generally considered to be symptom-free, which is controversial. Many authors emphasize that residual symptoms, such as emotional reactivity disturbance, are under-evaluated.

The aim of this study was to compare emotional reactivity between normothymic bipolar patients and healthy controls.

We evaluated emotional reactivity in 26 normothymic bipolar patients and 30 controls, using an emotional induction method based on the viewing of a set of 36 pictures (12 negative, 12 neutral, 12 positive) extracted from the International Affective Picture System. We evaluated subjective emotional reactivity (valence and arousal) with the Self-Assessment of Manikin and physiological reactivity measuring the pupil response with an eye-tracking material.

No difference was found between normothymic bipolar patients and controls regarding the subjective emotional reactivity. However, the dilatation of the pupil was significantly lower in normothymic bipolar patients during the viewing of positive pictures (p < 0.05).

Compared to controls, normothymic bipolar patients had less emotional reactivity to positive valence. This result is in coherence with the more frequent negative emotional bias (sadness, anxiety and anger) observed usually in bipolar patients. These preliminary results need to be replicated.