Changes in sexual behavior over recent decades have resulted in more people having multiple serial or concurrent sexual relationships during young adulthood.
A new longitudinal study investigates how these shifting trends affect mental health.
Key Facts:
- Researchers followed a cohort of nearly 1,000 New Zealanders from birth to age 32, tracking their sexual behavior and mental health.
- Having a higher number of sexual partners during three age periods (18-20, 21-25, and 26-32 years) did not increase risk of anxiety or depression later on.
- However, a higher number of partners was linked to substantially increased odds of developing alcohol or cannabis dependence, especially among women.
- For women reporting 2.5+ partners per year, the odds of later substance dependence were 7-17 times higher compared to women with 0-1 partners.
- The association persisted after accounting for prior substance use and mental health problems.
Source: Arch Sex Behav.
Changes in Sexual Trends Prompt Investigation of Mental Health Effects
Since the 1960s, the average age of first sexual intercourse has declined while the average age of first parenthood has increased.
As a result, today’s young adults spend more years being sexually active before settling down.
Surveys show increases in the number of lifetime and concurrent sexual partners compared to earlier generations.
Researchers from New Zealand sought to investigate how these shifting trends affect mental health.
They focused on three common disorders: anxiety, depression and substance dependence.
The Study: Tracking Sexual Partners and Mental Health from Ages 18-32
The researchers utilized data from the Dunedin Multidisciplinary Health and Development Study, an ongoing longitudinal study following the lives of 1,037 individuals born in 1972-73 in Dunedin, New Zealand.
The participants were assessed every 2-3 years from ages 3 to 15, then again at 18, 21, 26 and 32 years.
At each assessment they reported on their mental health symptoms and sexual behaviors over specific time periods.
Diagnoses of anxiety, depression and substance dependence were made based on DSM criteria.
The number of heterosexual partners over the past 1, 3, 5 or 6 years was determined at ages 21, 26 and 32.
The researchers categorized participants into groups based on number of partners per year: 0-1, 1.1-2.5, and 2.5+.
They then analyzed whether the number of partners during three age periods (18-20, 21-25, and 26-32 years) was associated with odds of mental disorders in the following 1-year period (at ages 21, 26 and 32).
Analyses accounted for prior mental health status.
No Link to Anxiety or Depression, But Higher Substance Dependence (Drug Addiction)
Number of Sex Partners
- 0-1 per year (reference group)
- 1.1-2.5 per year
- 2.5+ per year
Anxiety
No significant associations found between number of partners and odds of anxiety diagnosis at any age.
Depression
No consistent links seen between partners and later depression.
Slightly higher odds (OR 1.4-1.7) seen for those with 1.1-2.5 partners in some analyses, but results were inconsistent.
Substance Dependence
Women: Striking escalation in odds of developing substance dependence disorder with higher number of partners at all three age periods.
- Age 21: OR 9.6 for 2.5+ partners
- Age 26: OR 7.3 for 2.5+ partners
- Age 32: OR 17.5 for 2.5+ partners
Men: Increased odds of substance dependence also seen with more partners, but smaller magnitudes than women.
- Age 21: OR 4.3 for 2.5+ partners
- Age 26: No significant link
- Age 32: OR 2.6 for 2.5+ partners
Similar patterns found for alcohol and cannabis dependence individually.
Associations remained significant after accounting for prior substance use and mental health disorders.
Analyses Using Only New Cases of Disorders
The researchers also looked specifically at individuals who developed a disorder during the study period but did not have that disorder at the previous assessment.
This aimed to identify new cases.
The findings were:
- No significant associations between number of partners and new cases of anxiety or depression at any age.
- Women with 2.5+ partners continued to show markedly higher odds of developing new cases of substance dependence (though attenuated compared to overall group).
- Men showed weaker associations between partners and new substance dependence cases.
Evidence that more sex partners is linked to drug addiction
This longitudinal study provides evidence that having a higher number of sexual partners is linked to increased risk for developing substance dependence disorders later in life, especially among women.
The reasons behind this association are likely complex. Possibilities include:
- Clustering of risk-taking behaviors
- Substance use leading to sexual disinhibition
- Anxiety related to failed relationships or impersonal sex prompting self-medication
- Conflict between behavior and traditional gender norms causing internal distress
Overall, the findings highlight a potential unintended consequence of today’s sexual norms.
They also underscore important gender differences in the interplay between sexual experiences and mental health.
The study’s key strengths included its longitudinal design, high participant retention, consistent measures over time and ability to account for previous disorders.
More research is needed to uncover the mechanisms driving this association and determine whether similar patterns are found across cultures.
But these results suggest the need for greater awareness and open communication around the potential mental health impacts of multiple sexual relationships, especially for young women.
References
- Study: The relationship between multiple sex partners and anxiety, depression and substance dependence disorders: a cohort study
- Authors: Sandhya Ramrakha et al. (2013)
