{"p"=>{"__content__"=>"Parent training and assisted self-help have proven effective in preschool-age children with attention-deficit/hyperactivity disorder (ADHD). This study analysed a stepped-care approach combining these interventions. Participants were children (3–6 years) with either ADHD or oppositional defiant disorder (ODD) plus substantial ADHD symptoms. Study Step 1 (three months) comprised a randomised, waitlist-controlled trial on the efficacy of parent-directed telephone-assisted self-help (TASH). Based on the response to TASH, in Step 2 (six months), participants either received TASH booster sessions (full responders) or participated in another randomized controlled trial (partial/non-responders) comparing parent management and preschool teacher training (PMPTT) with treatment as usual (TAU). The primary outcome was change in blinded-clinician-rated ADHD and ODD symptoms. The primary analyses were by intention-to-treat. 189 children (79.9% boys, mean age = 5.1 years) were randomised. A univariate analysis of covariance did not yield a significant difference in the primary outcome for Step 1 (=58, =54; mean difference  -0.13 ± 0.07, 95%- -0.26–0.01;  = 0.06; = -0.30). Following TASH, 67 children (40.9%) showed a full response and 97 a partial/non-response. In Step 2, PMPTT was superior to TAU (=23, =37; mean difference -0.23 ± 0.11, 95%- -0.44–[-0.01];  = 0.040; =-0.52, 95%- -1.02–[-0.03]). Furthermore, TASH showed effects on parent-rated externalizing symptoms, negative parenting, and parental self-efficacy, and PMPTT on semi-blinded-clinician- and parent-rated impairment. Stepwise adaptive treatment may be beneficial for preschoolers with ADHD. Initial TASH is associated with full responses in a subgroup. Consecutive PMPTT should be offered to children with residual symptoms. (German Clinical Trials Register; DRKS00008971; registered on 01 October 2015).", "i"=>[{"__content__"=>"n"}, {"__content__"=>"n"}, {"__content__"=>"CI"}, {"__content__"=>"p"}, {"__content__"=>"d"}, {"__content__"=>"n"}, {"__content__"=>"n"}, {"__content__"=>"CI"}, {"__content__"=>"p"}, {"__content__"=>"d"}, {"__content__"=>"CI"}], "sub"=>[{"__content__"=>"TASH"}, {"__content__"=>"Waitlist"}, {"__content__"=>"PMPTT"}, {"__content__"=>"TAU"}]}}