Recurrent tension headache in adolescents treated with self-help relaxation training and a muscle relaxant drug. Forty-eight adolescents suffering from recurrent tension headache participated in a controlled trial conducted in a high school setting. During the first treatment phase self-help relaxation training was compared with a waiting-list group. Following this phase a pharmacological regimen consisting of a muscle relaxant (chlormezanone) and placebo was superimposed on relaxation therapy in a double-blind crossover design. Each treatment phase encompassed a 5-week period. In addition to the evaluation of headache complaints, psychological distress among students was measured with respect to their experience of somatic complaints, depressive, anxiety and stress symptoms. Although self-help relaxation training significantly decreased the severity and annoyance of adolescents' headache besides their somatic complaints, the clinical improvement of headache was modest. The addition of chlormezanone did not help those who were nonresponders to self-help relaxation training. Finally, a set of pretreatment variables consisting of baseline headache severity and annoyance, experience of anxiety and daily life stress among adolescents could predict outcome of self-help relaxation therapy. 