To assess the impact of maternal attention-deficit/hyperactivity disorder (ADHD) symptoms on the effectiveness of a parent training (PT) program for preschool ADHD.

Eighty-three 3-year-old children with ADHD and their mothers selected from two community cohorts living in Hampshire, England (1992–93 and –96, respectively), completed an 8-week PT program. ADHD symptoms and a number of other parent and child factors, including adult ADHD symptoms, were measured prior to the start of treatment (week 1: T₁), immediately after treatment (week 8: T₂), and at 15 weeks follow-up (week 23: T₃).

Mothers were divided into three groups on the basis of their scores (T₁) on the Adult AD/HD Rating Scale (high, medium, low). Children of mothers in the high-ADHD group displayed no improvement after PT, whereas the levels of ADHD symptoms of the children of mothers in either the medium or low ADHD groups reduced substantially (F_4,160 = 3.13, p < .05). This association persisted after other child and maternal factors were controlled for in multiple regression analyses (β > .30, p < .05).

High levels of maternal ADHD symptoms limit the improvement shown by children with ADHD after a program of PT. This effect was unrelated to other aspects of maternal mental health and child functioning. The treatment of parental ADHD may be a prerequisite for the success of psychosocial interventions for childhood ADHD.