1. ¹Centre for Adolescent Health, Murdoch Childrens Research Institute, Royal Children's Hospital, The University of Melbourne, Victoria, Australia
2. ²Murdoch Childrens Research Institute, University of Melbourne Department of Paediatrics, Royal Children's Hospital, Victoria, Australia
3. ³School of Population Health, The University of Melbourne, Victoria, Australia

Correspondence: Dr CA Olsson, Murdoch Childrens Research Institute, Royal Children's Hospital, 2 Gatehouse Street, Parkville 3052 Melbourne, Australia. E-mail: craig.olsson@rch.org.au

Received 9 September 2004; Revised 5 January 2005; Accepted 24 February 2005; Published online 26 April 2005.

Abstract

The serotonin transporter gene (5-HTT) encodes a transmembrane protein that plays an important role in regulating serotonergic neurotransmission and related aspects of mood and behaviour. The short allele of a 44 bp insertion/deletion polymorphism (S-allele) within the promoter region of the 5-HTT gene (5-HTTLPR) confers lower transcriptional activity relative to the long allele (L-allele) and may act to modify the risk of serotonin-mediated outcomes such as anxiety and substance use behaviours. The purpose of this study was to determine whether (or not) 5-HTTLPR genotypes moderate known associations between attachment style and adolescent anxiety and alcohol use outcomes. Participants were drawn from an eight-wave study of the mental and behavioural health of a cohort of young Australians followed from 14 to 24 years of age (Victorian Adolescent Health Cohort Study, 1992 - present). No association was observed within low-risk attachment settings. However, within risk settings for heightened anxiety (ie, insecurely attached young people), the odds of persisting ruminative anxiety (worry) decreased with each additional copy of the S-allele (30% per allele: OR 0.77, 95% CI 0.62–0.97, P=0.029). Within risk settings for binge drinking (ie, securely attached young people), the odds of reporting persisting high-dose alcohol consumption (bingeing) decreased with each additional copy of the S-allele (35% per allele: OR 0.74, 95% CI 0.64–0.86, P<0.001). Our data suggest that the S-allele is likely to be important in psychosocial development, particularly in those settings that increase risk of anxiety and alcohol use problems.