BACKGROUND: The purpose was to examine the association between aspects of alienation and symptom load among adolescents. Furthermore an integrated purpose was to construct and validate an index of alienation. METHODS: Cross-sectional data from 5205 school children aged 11-15 years from a random sample of schools in Denmark were used. Data stems from the Danish contribution to the cross-national study Health and Behaviour in School-aged Children (HBSC). Alienation was measured with a new index fulfilling four criteria: (i) theoretical foundation, (ii) inter-correlation between items, (iii) correlation between each of the index's items and the outcomes and (iv) no differential item functioning. The final index included three indicators of alienation: helplessness, feeling left out of things and lack of confidentiality with parents. Symptom load was measured by HBSC Symptom Checklist and divided into physical and psychological symptoms respectively. High symptom load was defined as experiencing at least one symptom on a daily basis. RESULTS: The odds-ratio (OR) for high symptom load increased with the degree of alienation. For students with all three indicators of alienation, the OR for high physical symptom load was 2.49 (1.05-5.87). The OR for high psychological symptom load for the corresponding degree of alienation was 6.50 (3.11-13.56). CONCLUSION: The index of alienation fulfilled psychometric criteria for scalability. Furthermore the analyses showed a graded and significant association between alienation and high symptom load. This suggests alienation to be taken into account in future health interventions among adolescents. In school settings this may be done using principles of empowerment.