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The Multimodal Treatment Study of Children with ADHD - referred to as the MTA Study - is the largest treatment study of ADHD ever conducted. The study began with 579 children aged 7-10-years-old who were diagnosed with the combined type of ADHD. These children were randomly assigned to 1 of 4 treatment conditions: medication management, behavior modification, medication management + behavior modification (i.e., combined treatment), or community care (CC). Children assigned to the community care condition received whatever treatment their parents chose to pursue for them in their community.
The medication and behavioral treatment provided in the MTA study were far more rigorous than what children typically receive in community settings. Medication treatment began with an extensive double-blind trial to determine the optimum dose and medication for each child, and the ongoing effectiveness of children's treatment was carefully monitored so that adjustments could be made when necessary.
The behavioral intervention included over 25 parent training sessions, an intensive summer camp treatment program, and extensive support provided by paraprofessionals in children's classrooms. In contrast, children in the community care condition (CC) received whatever treatments parents opted to pursue for their child in the community. Although this included medication treatment for the majority of children, treatment was not conducted with the same rigor as it was for children who received medication treatment from the MTA researchers.
The initial results from this landmark study examined children's outcomes 14 months after treatment began. Although results from this complex study do not lend themselves to a brief summary, the overall pattern suggested that children who received intensive medication management - either alone or in combination with behavior treatment - had more positive outcomes than children who receive behavior therapy alone or community care, but only for core symptoms of ADHD, i.e. concentration, focus, and attention. The outcome however, was no better for other symptoms of ADHD and a myriad of related problems seen in ADHD, including parent-child relations, oppositional behavior, reading, and social skills, among others. There was also modest evidence that children who received combined treatment of behavior therapy plus medication were doing better overall than children who received medication treatment alone.
Treatment within the MTA Study ended at 14 months at which point parents pursued whatever treatment options for their child that they felt would be best. Outcome data collected from that point forward thus provides information about whether there were enduring benefits associated with the intensive medication management provided in MTA.
The second major outcome paper from this study reported on how children were doing at 24 months - (10 months after treatment provided by the study team had ended). In general, results were similar to those found at 14 months in that children who had received intensive medication treatment - either alone or in combination with behavior therapy - had lower levels of core ADHD symptoms and ODD symptoms compared to children who received intensive behavior therapy or community care. The magnitude of these differences, however, was about half the size that they had been at 14 months. Outcomes in other important domains, i.e., social skills, reading achievement, and parents' disciplinary strategies, did not differ between the groups. This indicates that the initial positive benefits of medication treatment were declining as time went on.
Recently, the MTA Study Group published results from their 3-year follow-up study [Jensen et.al. (2007). 3-year follow-up of the NIMH MTA Study. Journal of the American Academy of Child and Adolescent Psychiatry, 46, 989-1002] at which time they were able to reassess 485 of the original 579 participants. These data provide important information on how children were doing nearly 2 years after their treatment in the MTA study ended. As noted above, parents had pursued whatever treatment options - if any - they felt were best for their child during this period.
RESULTS
The 3-year follow-up assessment focused on 5 important outcome domains: parent and teacher ratings of ADHD and ODD symptoms, reading achievement scores, social skills, and functional impairment. These data thus provide a broad overview of how participants were doing 2 years after MTA treatment had ended.
Change in Core Outcomes
In contrast to the results obtained at 14 and 24 months, significant benefits of intensive medication management - either alone or in combination with behavior therapy - were not found for any of the key outcomes. Thus, 2 years after treatment ended, children who received intensive treatment from MTA researchers were not doing any better than those who had received routine community care or behavior therapy.
It is important to note that children in all groups were now doing substantially better than when the study began. On average, all groups showed substantial reductions in ADHD symptoms, ODD symptoms, and impairment, with the biggest decline evident for core ADHD symptoms. Ratings of social skills had also improved significantly; there was less evidence for improvement in reaching achievement scores.
Change in Diagnostic Status
The authors also examined the proportion of children originally assigned to each group (i.e., medication management, behavior therapy, combined treatment, and community care) who continued to meet full diagnostic criteria for ADHD. At baseline, 100% of children met criteria, as this was required to be in the study. After 14 months of treatment, approximately 60% of children in the behavior therapy and community care groups continued to meet criteria compared to only 40% of children in the medication management and combined treatment groups. This difference was largely preserved at the 24-month assessment but was no longer evident at the 36-month follow-up, where it was roughly 45-55% for children in all groups. Rates of comorbid disorders, i.e., Oppositional Defiant Disorder, Conduct Disorder, anxiety disorders, and depressive disorders, also declined significantly in all groups.
Change in Medication Treatment
To examine a possible reason why superior outcomes associated with careful medication management had decreased over time, the authors examined changes in the proportion of children receiving medication treatment at each follow-up assessment.
Medication use had changed substantially over the 3-year period. At the initial 14-month outcome assessment, 90% of children assigned to the medication management and combined condition were considered to be high medication users, defined as taking it at least 50% of the time, compared to 60% of children in the community care group and 14% of children in the behavior therapy group. The latter figure reflects the fact that some parents whose child was assigned to receive behavior therapy chose to add medication treatment during the initial 14 months.
By 24 months, medication use had dropped to roughly 70% of children originally assigned to the medication management and combined treatment groups; it remained at this level at 36 months. The proportion of children in the community care group who received medication remained steady at about 60 percent, whereas medication use for children assigned to behavior therapy increased to 45% by the 36-month assessment. Thus, one possible explanation for why the initial treatment differences had dissipated is that the groups were now far more similar in regards to the proportion taking medication.
Interestingly, continuation of medication treatment from 24 to 36 months was associated with an increase in symptomatology relative to those not taking medication.
Summary and Implications
Results from this 3-year follow-up study indicate that the modest but significant advantages associated with the careful medication management provided by the MTA researchers were completely lost by 36 months. As the authors point out, however, it would be "...incorrect to conclude from these results that treatment makes no difference or are not worth pursuing." Instead, intensive medication management "...may only make a persistent long-term difference if it is continued with the same intensity as during the MTA's initial 14-month period." Alternatively, the initial benefits of medication may simply not endure beyond the first year. This may be why those who had behavior therapy had a better long term outcome than those with medication alone.
Perhaps the most important result from this study is the improvement that was evident in all 4 groups. Between baseline and the 36-month follow-up, significant reductions were found for ADHD, ODD symptoms, and general impairment, while ratings of social skills increased. Rates of comorbid conditions had also declined. This was the case regardless of which treatment group children had been originally assigned to. Thus, while other follow-up studies have highlighted the ongoing difficulties that many children with ADHD experience, these results provide an important source of hope and encouragement for children and families and help to balance the negative outcomes that have been previously reported. These results reaffirm what many other studies have shown; any treatment is better than no treatment.
Of course, these encouraging findings do not negate the fact that many children with ADHD continue to experience significant struggles. Indeed, roughly 50% of children continued to meet full diagnostic criteria for ADHD at the 36-month follow-up. How these children continue to fare as they move into adolescence and early adulthood also remains to be seen. At this point, however, the trends towards improvement are certainly encouraging.
In future work, the MTA researchers will continue to follow these participants to develop new information and understandings of the developmental course of ADHD.
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