Psychosocial ADHD Interventions - Brief Parent Training

Inclusion Criteria: * A) The child is diagnosed with ADHD according to DSM-5 as measured by the Parent Interview for Child Symptoms \[PICS\] and the Teacher Telephone Interview \[TTI\] or; B) The child has at least four impairing symptoms of ADHD (at least four symptoms of ADHD as measured by the Parent Interview for Child Symptoms \[PICS\] and at least two symptoms measured by the Teacher Telephone Interview \[TTI\]; and significant impairment rated \>3 on the Impairment Rating Scale \[IRS\]). * The child is between four up to and including eleven years old and is attending a Dutch primary school. * The child has an IQ higher than 70. If an IQ-score is not available, this will be estimated with two subtests of the Wechsler Intelligence Scale for Children-V (Dutch edition; WISC-V-NL) or the Wechsler Preschool and Primary Scale of Intelligence-III (Dutch edition; WPSSI-III-NL). * Parents/caregivers have given their informed consent for participation. Exclusion Criteria: * Parents received behavioral parent training (individual or group) aimed at ADHD or behavioral problems of the child in the past year. * The child is currently taking psychotropic medication or has taken psychotropic medication in the past month. * The child has a DSM-5 or a DSM-IV-TR based diagnosis of an Autism Spectrum Disorder. * There are problems with the child and/or the family that require immediate intensive intervention (e.g., crisis in the family). * The child does not live in one household durin…