Abstract
Objective: This study investigated the effects on mental health of multiple sex partners; specifically whether higher numbers of partners are linked to later anxiety, depression and substance dependency.
Methods: Data from the Dunedin Multidisciplinary Health & Development Study, a prospective, longitudinal study of a birth cohort born in 1972-73 in Dunedin, New Zealand were used. The relationship between numbers of sex partners over three age periods (18-20, 21-25 & 26-32 years) and diagnoses of anxiety, depression and substance dependence disorder at 21, 26 and 32 years were examined, using logistic regression. Interaction by gender was examined. Adjustment was made for prior mental health status.
Results: There was no association between number of sex partners and later anxiety and depression. Increasing numbers of sex partners were associated with increasing risk of substance dependence disorder as all three ages. The association was stronger for women and remained after adjusting for prior disorder. For women reporting 2.5 or more partners per year, compared to 01 partner, the adjusted Odd Ratios (and 95% CIs) were 9.6(4.4-20.9), 7.3(2.5-21.3), and 17.5(3.5-88.1) at 21, 26, and 32 years respectively. Analyses using new case of disorder showed similar patterns.
Conclusions: This study has established a strong association between number of sex partners and later substance disorder, especially for women, which persists beyond prior substance use and mental health problems more generally. The reasons for this association deserve investigation