BackgroundThe triple network model of psychopathology posits that altered connectivity between the Salience (SN), Central Executive (CEN), and Default Mode Networks (DMN) may underlie neurodevelopmental conditions. However, this has yet to be tested in a transdiagnostic sample of youth.MethodsWe investigated triple network connectivity in a sample of 175 children (60 girls) that represent a heterogeneous population who are experiencing neurodevelopmental difficulties in cognition and behavior, and 60 comparison children (33 girls) without such difficulties. Hyperactivity/impulsivity and inattention were assessed by parent-report and resting-state functional Magnetic Resonance Imaging data were acquired. Functional connectivity was calculated between independent network components and regions of interest. We then examined whether connectivity between the SN, CEN and DMN was dimensionally related to hyperactivity/impulsivity and inattention, whilst controlling for age, gender, and motion.ResultsHyperactivity/impulsivity was associated with decreased segregation between the SN, CEN, and DMN in at-risk children, whereas it was associated with increased segregation of the CEN and DMN in comparison children. We replicated these effects in networks and regions derived from an adult parcellation of brain function and when using increasingly stringent exclusion criteria for in-scanner motion.ConclusionsTriple network connectivity characterizes transdiagnostic neurodevelopmental difficulties with hyperactivity/impulsivity. This may arise from delayed network segregation, difficulties sustaining CEN activity to regulate behavior, and/or a heightened developmental mismatch between neural systems implicated in cognitive control relative to those implicated in reward/affect processing.