Can Incredible Years improve symptoms of ADHD for Portuguese children?

Young girl looking at Nazare, Portugal with a telescope
Can Incredible Years improve symptoms of ADHD for Portuguese children?
10 February 2014

Research from the United States and several other nations shows that parent training programs can result in big improvements in parents’ skills and children’s behavior. With a 30-year history, Incredible Years (IY) is one of the most longstanding and well-evaluated parent training programs.

But what works in one location and culture may not work in another. Can a translated version of Incredible Years have the same effect in Portugal?

An answer from Portugal’s first randomized trial of Incredible Years is now in, with impressive results. In a group of children with attention and hyperactivity problems, 43% of the children whose parents participated in IY had clinically significant improvements in their ADHD, compared to 11% of the waitlisted group.

Mothers’ parenting skills improved, too, according both to mothers’ own reports and independent observations. Most of the benefits for both children and mothers continued to persist a year after the start of the program.

Evaluating Incredible Years in Portugal
These encouraging results come from two new reports an ongoing randomized control trial in Portugal, assessing the implementation of a translated version of Incredible Years. Researchers from Coimbra University analyzed a subsample of 100 children whose parents reported high levels of inattention and hyperactivity behaviors in their children. They measured the children’s ADHD symptoms and the mothers’ parenting skills and confidence before the program and at six- and 12-month follow-ups.

The ADHD analysis comes from a wider trial involving Portuguese preschoolers who were considered at risk of disruptive behaviors, and their parents. Families were randomly assigned to the Incredible Years program or to a waitlist control group. Although both fathers and mothers were invited to attend IY, only a third of fathers participated in the assessments, so all the analyses relate to mothers.

Parents were invited to attend 14 structured group sessions of Incredible Years, provided by accredited facilitators. Attendance was relatively high: 88% of the mothers attended nine or more of the sessions (two-thirds of the program). During sessions parents were taught skills through video presentations and group discussions, and were able to practice their new skills.

Researchers used 10 measures to rate children’s ADHD behaviors, including reports from mothers, reports from teachers, and direct observation of parent-child interaction during a laboratory task. They also used eight measures of parenting, including mothers’ self-reports and behaviors observed in the lab.

Positive findings at six months
Six months after the start of the study, IY made a difference for children’s behavior on several measures. In general, both groups of children improved, but the IY group improved more than the control group.

Compared to the control group, children in the IY group had much larger improvements in hyperactivity and attention levels, according to both mothers’ reports and preschool teachers’ reports.

However, the difference between intervention and control groups in oppositional behavior and in social skills was more modest, according to mothers’ reports. Preschool teachers reported no notable difference in social skills between the two groups.

As for parents’ behavior and confidence, mothers in the intervention group were more likely to report higher confidence in their parenting skills, and to rate their parenting as more positive than at baseline, compared to mothers in the control group.

Sustained at 12 months
Of course, it’s always an important question whether positive results of a program will fade out over time – or grow as new habits take hold and “sleeper effects” kick in. In this case, most of the improvements that resulted from IY at six months were still visible after a year.

Researchers compared children’s scores 12 months after the program to their scores at baseline and six months after participation. Children were not compared to a control group, as the waitlist had received the intervention by this time.

The improvements in children’s hyperactivity and attention reported by both mothers and teachers remained steady between the six-month and 12-month follow-ups.

In addition, mothers who had participated in IY “continued [after a year] to use positive parenting skills and less harsh and dysfunctional practices, and were feeling more effective in parenting.” These sustained improvements in parents’ skills and confidence are seen as crucial for supporting preschoolers with ADHD behaviors, since these children may be more sensitive than most to negative parenting.

One exception was the lab observation of parents’ coaching techniques. Coaching had improved somewhat among IY mothers after the program, but at the 12-month follow-up these skills were rated as worse than at baseline. The researchers speculated that a longer program, or more work specifically on coaching, would be necessary to develop and sustain these skills.

Overall, “after 12 months of follow-up, there was a clinically important reduction in reported ADHD behaviors in 59% of children.”

Limitations and implications
As the first study of its kind in Portugal, this trial is not conclusive evidence of the effectiveness of the Incredible Years program in the new context. The 12-month follow-up results have some particular limitations because the original control group had by that time been offered the IY program, so comparisons had to be made to previous measurements rather than to a control group.

Preschool teachers and observers at 12 months were also aware which children had participated in the program, and this may have affected how raters viewed children’s behavior.

In addition, at the 12 month time point, 27% of the children were receiving additional support, including medication or outpatient support. The analysis did not consider the impact of receiving extra support, which may have affected the findings.

Finally, the trial organizers paid exceptional attention to the quality and fidelity of treatment. The six IY facilitators each had at least 10 years of prior experience in clinical child psychology or psychiatry, went through IY accreditation training, had run pilot groups, and had ongoing support from IY trainers. While experienced and well-supported leaders may help to explain the positive results from this trial, recruiting and supervising many similar individuals is a constant challenge for implementing programs on a larger scale.

ADHD can set children on a track of poor behavior, school failure, and frustrating relationships between children and their parents. This study provides strong, if preliminary, evidence that parenting programs such as IY can be successfully adapted for children with challenging behaviors and their families in the Portuguese context.


Azevedo, A. F., Seabra-Santos, M. J., Gaspar, M. F., & Homem, T. (2013). The Incredible Years Basic Parent Training for Portuguese preschoolers with AD/HD behaviors: Does it make a difference? Child & Youth Care Forum, 42, 403-424.

Azevedo, A. F., Seabra-Santos, M. J., Gaspar, M. F., & Homem, T. (2013). A parent-based intervention programme involving preschoolers with AD/HD behaviours: Are children’s and mothers’ effects sustained over time? European Child & Adolescent Psychiatry, doi: 10.1007/s00787-013-0470-2.


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