[Recognition of facial expressions of emotions by 3-year-olds depending on sleep and risk of depression]

Abstract

Introduction: The emotional process is characterized by a negative bias in depression, thus it was legitimate to establish if they same is true in very young at-risk children. Furthermore, sleep, also proposed as a marker of the depression risk, is closely linked in adults and adolescents with emotions. That is why we wanted first to better describe the characteristics of emotional recognition by 3-year-olds and their links with sleep. Secondly we observed, if found at this young age, an emotional recognition pattern indicating a vulnerability to depression.

Material and method: We studied, in 133 children aged 36 months from the AuBE cohort, the number of correct answers to the task of recognition of facial emotions (joy, anger and sadness). Cognitive functions were also assessed by the WPPSI III at 3 years old, and the different sleep parameters (time of light off and light on, sleep times, difficulty to go to sleep and number of parents' awakes per night) were described by questionnaires filled out by mothers at 6, 12, 18, 24 and 36 months after birth. Of these 133 children, 21 children whose mothers had at least one history of depression (13 boys) were the high-risk group and 19 children (8 boys) born to women with no history of depression were the low-risk group (or control group).

Results: Overall, 133 children by the age of 36 months recognize significantly better happiness than other emotions (P=0.000) with a better global recognition higher in girls (M=8.8) than boys (M=7.8) (P=0.013) and a positive correlation between global recognition ability and verbal IQ (P=0.000). Children who have less daytime sleep at 18 months and those who sleep less at 24 months show a better recognition of sadness (P=0.043 and P=0.042); those with difficulties at bedtime at 18 months recognize less happiness (P=0.043), and those who awaken earlier at 24 months have a better global recognition of emotions (P=0.015). Finally, the boys of the high-risk group recognize sadness better than boys in the control group (P=0.015).

Conclusion: This study confirms that the recognition of emotion is related to development with a female advantage and a link with the language skills at 36 months of life. More importantly, we found a relationship between sleep characteristics and emotional recognition ability and a negative bias in emotional recognition in young males at risk for depression.

Keywords: Child; Depression; Dépression; Emotion; Enfant; Facteur de vulnérabilité; Sleep; Sommeil; Vulnerability factor; Émotion.