Study aims

Within this two-armed, double-blind, randomized controlled trial we aim to test the hypothesis that moderate to severely depressed children and adolescents (BDI-II sum score at admission > 13) with a vitamin D deficiency (25(OH)-D3 level < 30 nmol/l [equivalent to < 12 pg/ml]) who will be treated as usual, but will not be supplemented with vitamin D (placebo arm) for a period of at maximum 28 days, will end-up with a significantly higher BDI-II sum score, than those immediately supplemented with 2640 I.U. vitamin D3 q.d. (verum arm). The assessment of the vitamin D status is not part of current routine diagnostic in clinical psychiatric departments or psychiatric offices. This study is to the best of our knowledge the first randomized controlled trial (RCT) investigating the effect of watchful waiting with regard to vitamin D supplementation in children and adolescent inpatients with an elevated depression score. The primary outcome parameter is the BDI-II sum score. Secondary outcome parameters encompass the 25(OH)-D levels from baseline to study end as well as impulsiveness and depressive symptoms assessed with parent- and self-rating instruments.