Adverse Effects of Well-Intentioned Interventions to Improve Outcomes in Adolescence

We recently reported on the evaluation of a study to reduce aberrant teenage behaviour that had a negative effect – i.e. it actually increased the behaviour it was designed to prevent. On further enquiry, it turns out that this is but one of a series of studies targeting adolescent behaviour, that showed effects opposite to those intended.[1] The classic study, quoted by Dishion, McCord & Poulin, was the Cambridge-Sommerville Youth Study.[2] [3] This was a randomised study of matched pairs of adolescent boys (irrespective of previous behaviour) in a run-down neighbourhood. The intervention consisted of visits (an average of twice a month) by counsellors who also took the boys to sporting events, gave them driving lessons, and helped them and their family members apply for jobs. The intervention had harmful effects on arrests, alcohol problems, and mental hospital referral on follow-up 40 years later.[4] [5] In a sub-group comparison, boys sent to summer school more than once had a particularly bad outcome. This is consistent with the theory that mutual interaction reinforces behaviour problems among susceptible adolescent boys.

On the basis of this RCT and other randomised studies, one of which was cited in the previous post, “there is reason to be cautious and to avoid aggregating young high-risk adolescents into intervention groups.” Apparently interventions targeted at parents are more positive in their effects. CLAHRC WM has a large theme of work on adolescent health and the Director invites comments from inside and outside our organisation.

— Richard Lilford, CLAHRC WM Director


  1. Dishion TJ, McCord J, Poulin F. When Interventions Harm. Peer Groups and Problem Behaviour. Am Psychol. 1999; 54(9): 755-64.
  2. Healy W, & Bronner AF. New Light on Delinquency and its Treatment. New Haven, CT: Yale University Press. 1936.
  3. Powers E, & Witmer H. An Experiment in the Prevention of Delinquency: The Cambridge-Sommerville Youth Study. New York: Columbia University Press. 1951.
  4. McCord J. A Thirty-Year Follow-Up of Treatment Effects. Am Psychol. 1978; 33: 284-9.
  5. McCord J. Consideration of Some Effects of a Counseling Program. In: Martin SE, Sechrest LB, Redner R (Eds.) New Directions in the Rehabilitation of Criminal Offenders. Washington, D.C.; The National Academy of Sciences. 1981. p.394-405.

2 thoughts on “Adverse Effects of Well-Intentioned Interventions to Improve Outcomes in Adolescence”

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s