The challenges to demonstrating long-term effects of psychostimulant treatment for attention-deficit/hyperactivity disorderHazell, PhilipCurrent Opinion in Psychiatry: July 2011 - Volume 24 - Issue 4 - p 286–290 doi: 10.1097/YCO.0b013e32834742db Child and adolescent psychiatry: Edited by Richard Williams and Philip Hazell Abstract Author Information Purpose of review Questions about the long-term effects of psychostimulant medication are frequently raised in the public domain. There is a need to articulate the methodological challenges to addressing this question, both to assist in the interpretation of existing research and to inform future research. Recent findings Two peer-reviewed studies and one published report have attempted to address the issue of long-term effects of psychostimulant medication. One is favourable, one found no benefit, and the third showed harm. All three studies struggled to deal with methodological challenges such as the variable time course of the disorder, variability in persistence and adherence with treatment, and self-selection for treatment continuation. Summary Future research examining the long-term effects of psychostimulant treatment will of necessity be naturalistic, but must be able to control for treatment quality, treatment adherence, and natural variation in the course of attention-deficit/hyperactivity disorder. It would be helpful to distinguish between long-term effects of treatment and effects of long-term treatment. Discipline of Psychiatry, Sydney Medical School, Sydney, Australia Correspondence to Professor Philip Hazell, Rivendell, Thomas Walker Hospital, Hospital Rd, Concord West, NSW 2138, Australia Tel: +61 2 97362288; fax: +61 2 97436264; e-mail: email@example.com © 2011 Lippincott Williams & Wilkins, Inc.