Attention-Deficit/Hyperactivity Disorder (ADHD) is connected with high level of psychiatric comorbidity in paediatric population. Depressive disorder is common comorbid disorder co-existing with ADHD. Atomoxetine is worldwide approved for treatment of ADHD in paediatric population; in addition atomoxetine is effective and safe in treatment of some comorbid disorders in ADHD. Pharmacotherapy of depression is limited and residual symptoms are common. Fluoxetine is currently considered to be the gold standard of treatment of depression, but effectiveness of acute phase of treatment is not sufficient. Atomoxetine as a selective noradrenaline reuptake inhibitor or olanzapine as a multi receptors antagonist drug in combination with fluoxetine could be perspective augmented treatment strategy of depression just for their antidepressant effect. The aim of our following study is to evaluate and compare effectiveness and safety of monotherapy and combined/augmented therapy in acute phase of depression treatment in adolescence, as well as introduce complex modern research methodology of effectiveness and safety of treatment.