Les périodes de normothymie dans les troubles bipolaires sont classiquement considérées comme étant indemnes de troubles psychiatriques avérés. Cependant, des résultats récents évoquent la possibilité d’une dysrégulation émotionnelle même au cours de ces périodes. L’objectif de cette étude est donc d’étudier la réactivité émotionnelle des patients bipolaires en phase de normothymie par rapport à un groupe témoin.

La réactivité émotionnelle de 145 sujets (90 témoins et 55 patients bipolaires en phase normothymique) a été évaluée au moyen d’une méthode d’induction émotionnelle basée sur le visionnage d’un set de 18 images à tonalité positive, négative ou neutre. Nous avons mesuré et comparé l’évaluation subjective de la valence (plaisant, neutre ou déplaisant) et l’intensité émotionnelle ressentie (éveil plus ou moins intense).

Les patients bipolaires normothymiques attribuent en moyenne la même valence et la même réactivité émotionnelle que les témoins face aux images positives et négatives. En revanche, les images neutres sont évaluées comme étant plus plaisantes et plus émouvantes par les patients bipolaires normothymiques que par les témoins.

Les patients bipolaires en phase de normothymie semblent avoir une hyperréactivité émotionnelle qui se manifeste particulièrement en situation neutre. Cette hypersensibilité pourrait être liée à une dysrégulation émotionnelle, possible endophénotype de la pathologie bipolaire.

Euthymic states in bipolar disorders are usually considered to be lacking serious psychiatric disorders. Moreover, recent results prove the need to take an interest in a potential emotional dysregulation during these intercrisis periods. Therefore, it seems relevant not only to focus on the emotions tonality (sadness/euphoria) felt by patients, but also on the intensity of their emotional background. Several reasons argue for a disturbance of emotional reactivity in euthymic bipolar patients. First, most bipolar patients spontaneously claim they have a higher sensitivity than average, which may lead to extreme emotional reactions, even during intercrisis periods. Secondly, the emotional reactivity is a way to raise the question of the bipolar patients’ vulnerability to stress in euthymic periods. Several studies have shown the impact of stressful life events on the rate of relapse into bipolar disorders. The aim of this study is to examine the emotional reactivity of euthymic bipolar patients in comparison with a control group, using a test of emotional induction. Our hypothesis is that euthymic bipolar patients have a higher emotional reactivity than controls.

One hundred and forty-five subjects were recruited: 90 controls and 55 euthymic bipolar patients. The patients were interviewed by a trained psychologist using the French version of the DIGS providing DSM-IV diagnosis. The euthymic state was confirmed with both MADRS (score<12) and Bech’s Manic Scale (score<4). The subjective emotional reactivity of the subjects was assessed using a method of emotional induction, based on viewing a set of 18 (positive, negative or neutral) pictures. The subjects have to appreciate the valence (pleasant, neutral or unpleasant thoughts) and assess the arousal (degree of emotion triggered by each picture).

On average, euthymic bipolar patients report the same valence and arousal to positive (F [1.143]=0.18, p=0.68) and negative (F [1.143]=0.52, p=0.47) pictures as control subjects. Neutral pictures, however, were considered more pleasant and moving by euthymic bipolar patients than by control subjects (F [1.143]=8.40, p=0.004).

Euthymic bipolar patients seem to present an emotional hyperactivity which occurs especially in neutral situations. These results partly corroborate outcomes of other authors, while providing a new methodology through the emotional induction test. The highlight of emotional hyperreactivity during intercrisis periods allows us to understand differently the topic of specific vulnerability to stress of bipolar patients. This hypersensitivity could lead to thymic decompensations and could be linked with an emotional dysregulation, potential endophenotype of the bipolar pathology. Beyond the interest in understanding the physiopathology of the bipolar disorder, it could be associated with several clinical applications as well as in the psychoeducational field and in the screening of the individual risk within the family of bipolar subjects.