Comorbidity of internalizing symptomatology in children and adolescents

This doctoral dissertation focuses on comorbidity of emotional disorders in children and adolescents. The internalizing psychopathologies studied here are: anxiety, somatization and depression. The three works of this doctoral thesis have been achieved using school children and adolescent general populations. The first work is about comorbidity of anxiety disorders and depression. We analysed this relation using CDI for depressive symptoms and SCARED for anxiety symptomatology. Within children with anxiety symptomatology, 87% reported homotypic comorbidity (that is, between the same nosology entity: anxiety disorders). In addition, 82% of those with depressive symptoms reported heterotypic comorbidity (that is, between different nosology entities: anxiety and depression), whereas 20% of those with anxiety also reported having depression. The most common homotypic and heterotypic comorbidities were separation anxiety + generalized anxiety and depression + separation anxiety, respectively. In the second work, which somatic symptoms are more comorbid with depression and anxiety were identified. Results of this paper not only lent some support to prior research which found that the presence of anxiety and depression contributes to the manifestation of somatization, but they have also shown that both depression and anxiety did not exert the same influence on all somatic symptoms. These findings suggested that depression was most associated with headache, stomach ache, fatigue, dizziness and muscle pain, whereas anxiety was only related to fatigue and muscle pain. The third paper is a comparative study of comorbidity of internalizing disorders between Spanish and Latin-American adolescents. From this paper, it seems clear that Spanish and Latin-American adolescents reported comorbidity and, although differences were not statistically significant, a higher percentage of Latinos showed co-occurrence of anxiety, depression and somatization. Comorbidity is an important construct due to its clinical implications in infant and adolescent mental health. There is today a common assumption that the existence of comorbid disorders complicates treatment and decreases its efficacy. On the other hand, many children and adolescents who seek medical health-care with somatic complaints should also be screened for possible depressive and anxiety symptoms. This information is especially relevant nowadays in Spain because primary health-care attends many Latin-American children and adolescents, and several Spanish paediatric patients are victims of the economic crisis, with an increasing number of somatizations.