“There’s always been a question about which one is the cause and which is the effect. This study provides evidence that poor mental health can lead to casual sex, but also that casual sex leads to additional declines in 
mental health.” Sandberg-Thoma conducted the study with Claire Kamp Dush, assistant professor of human sciences at Ohio State. The research was published online recently in the Journal of Sex Research and will appear in a future print edition. One surprising finding was that the link between casual sex and mental health was the same for both men and women. “That was unexpected because there is still this sexual double standard in society that says it is OK for men to have casual sexual relationships, but it is not OK for women,” Kamp Dush said. “But these results suggest that poor mental health and casual sex are linked, whether you’re a man or a woman.” Read More
I need to give a hat tip to Elizabeth Scalia for pointing my attention to this piece.
You’ll recall I asserted this exact same thing in my interview with drive time shock jock Tracy Jones on WKRP WLW in Cincinnati several months ago. The researchers seem mystified as to why it is that casual sex causes depression and why this is true for both women and men.
The Christians reading this will probably be face-palming right about now because we accept these facts–for the most part anyway (I think the male casual sex/depression link would surprise a lot of my Christian friends infected with the secular culture’s double standard about men)–as biblical truths. But we have to do a better job of explaining why casual sex is wrong beyond just saying “Jesus said, NO!” (as if he was “Grumpy Cat” or something)
As I assert in my book Holy Sex! the brain is wired to view sex as a sign of intimacy and unity. In fact, the brain responds to break-ups the same way it responds to physical pain. When two people make love, their brains begin to think of the other as part of each self. The lovers literally become wired together. When they break-up, the brain responds to the social wound as if the lovers experienced a physical wound; a broken arm or a broken leg. Now imagine intentionally setting yourself up to get physically wounded again and again. You would call that person “mentally ill” right? Well, that’s what casual sex is–setting your brain up to be wounded again and again. And setting oneself up to get hurt again and again–especially in the name of fun–is a depressing thought.
Sex is a powerful drug. In particular, it is a drug that literally bonds two people together–not just metaphysically, but neurologically. The brain can’t tell the difference between a one night stand and an LTR. It just knows that it is being bombarded by chemicals that make it start to bond with another person and think of that person as part of oneself. Losing a part of yourself is depressing. The brain processes a break-up after sex like it would process an amputation and, to respond to the other question the study asked, the reason that causal sex negatively affects both women and men is because male and female brains are more alike than they are different. Yes, there are differences between the sexes, but those differences tend to be more qualitative than structural. It isn’t as if women have entire swaths of brain territory that men don’t. It’s just that some areas of the female brain light up a little differently than other parts. But both men and women have all the parts of the brain that make them human beings, and the bonding process is a basic human response. The mental health of both men and women is negatively affected by casual sex because we weren’t physically made to do it, and acting in a manner that is contrary to our design causes us to feel broken down and depressed.
The good news is that the flipside is also true. People who have fewer sexual partners (for instance, one) and who remain faithful to that partner are happier, and both mentally and physically healthier than people with more sexual partners.
If you’d like to learn more about having a healthy, joyful, life-long love, or how to effectively articulate the truth of the Catholic vision of love, check out Holy Sex! A Catholic Guide to Toe-Curling, Mind-Blowing, Infallible Loving.