Background: Many patients with psychiatric illnesses have difficulty maintaining medication over time. Many take their medicine irregularly and studies show that it is the most vulnerable patients who have the greatest problems adhering to treatment. Often only 50% are still under medical treatment after 6 months. Aim: In this study we investigated whether text message reminders could improve medicine compliance amongst vulnerable young people with psychiatric disorders who were being treated in the outpatient department for child and adolescent psychiatry and who either are under or were to commence medicinal treatment. Methods: This study was conducted as a randomized controlled trial including all non-acute referrals to an outpatient department for adolescent psychiatry within a group aged 15-20 years starting medical treatment. The patients were followed until the end of their treatment, for a minimum of 3 months. To enhance medicine compliance, text messages were sent daily to one group. No message was sent to the other group. Results: Compliance was not associated with text message intervention in any of the drug interventions. The effect size was calculated to 0.3013, which is low and therefore indicates a weak association between text message and compliance. The power in this study was calculated to 0.3539, which is also low and therefore the likelihood of finding significant association is low. Conclusion: This study does not show increased medicine compliance from the text message intervention group. The conclusion of this study is that it is essential that significant resources are spent preparing and testing a text message strategy. © 2015 Taylor & Francis.