great. Do you know that ultrarelaxed feeling you get when you hold your baby? How about the bliss after you’ve just had orgasmic sex and are being held closely? That’s oxytocin, the hormone of bonding and of trust. A twenty-second hug will trigger oxytocin release, as will exchanges of friendly signals, like being smiled at and returning the grin. Think of oxy as superglue for your relationship. It cements a nursing mother and her child, and it bonds lovers from the first time their eyes lock across a crowded room. Holding hands, kissing, and sex will all get your oxy levels zooming. Smiling babies and hugs with boyfriends activate not only oxytocin release but also dopamine-associated brain reward circuits, encouraging us to keep doing it. In that way, you could say that oxytocin makes you crave even more physical contact. Oxytocin helps to protect us against stress and promote relaxation. There are even some studies showing it can help to speed healing. So hugging, cuddling, and orgasmic sex are good for not just your heart and soul but your body as well.
Women have more oxytocin receptors in their brains, and oxytocin works better in an environment rich with estrogen. So you may be more likely to connect and fall in love during the first half of your cycle, before estrogen levels drop. Oxytocin, in both men and women, creates feelings of trust, connection, and contentment around the preferred partner. Oxytocin reduces heart rate and blood pressure, enabling social bonding and trusting behaviors. A sense of calm and security quiets the typical fear of strangers, allowing more generosity. In experiments, people given oxytocin are more willing to trust a stranger or give them money. That may be the reason why people who are touched while spoken to are more likely to honor a request or keep a promise. It also may be why falling in love can be dangerous for some. I had a patient who lent way too much money to a new boyfriend who later disappeared.
Infatuation overrides rational thought. At higher levels of oxytocin, you may become forgetful, and your ability to think clearly may be diminished. Falling in love squelches anxiety and skepticism. Oxy, in particular, seems to be crucial for inhibiting fear and anxiety, allowing bonding and sex to occur. When people fall in love, their fear circuitry gets turned way down, so the critical thinking system (anterior cingulate cortex) and the fear center (amygdala) are less active. The brain’s Miracle-Gro fertilizer, a nerve growth factor called brain-derived neurotrophic factor (BDNF), which helps to foster new connections between nerve cells, is elevated in people who’ve fallen in love, triggering a massive neuronal reorganization. (Remember BDNF, because you’re going to be learning about it again. Neuroplasticity is involved in pregnancy, perimenopause, and exercise, and it’s important.) Tons of brain cells have to be “obliterated and replaced with new ones. This is one reason falling in love feels . . . like a loss of identity.” Is all of this dangerous? Probably not, but it’s good to keep your wits about you when falling in love. You’re not in your typically critical “right mind.” You’re not even yourself!
You’re My Obsession
Ask my husband about how we met and he’ll say he’s never been pursued by anyone more aggressively in his life. Ask me, and I’ll tell you about love at first sight. I remember every moment of that party where I set my eyes on him. I had to lock myself in the bathroom to calm down my breathing and pounding heartbeat (norepinephrine in action). In the days that followed, I would check countless times to see if he’d contacted me. All day long, I could think of nothing but him, Him, HIM.
It’s normal, it’s nature’s way, and it’s likely that lower than normal serotonin levels were underlying my obsessive thoughts and activities. When serotonin levels are high, there is a sense of satiety; you want for nothing. When levels are lower, you become obsessive and angsty. Blood serotonin levels in those newly in love resemble levels in people with OCD. They’re abnormally low for both, about 40 percent of the normal controls.
Dopamine and serotonin tend to act like they’re on opposite sides of a seesaw. When one is up, the other is often down. Infatuation and initial attraction are characterized by higher dopamine and lower serotonin levels. Higher serotonergic states make it harder to climax, as anyone on sertraline can tell you. So this low serotonergic state helps explain not only why it’s easier for you to climax with your new lover but also your tremendous feelings of angsty need and obsessive ruminations about your newfound love.
One thing I’d like to stress: women on SSRIs likely won’t experience some of the chemical cocktail of attraction and infatuation. SSRIs create artificially high serotonin levels, decreasing impulsive and compulsive behavior. You have more behavioral control, and you don’t obsess as much about anything, even if you just fell in love, which you may not even do on an SSRI. SSRIs interfere with mating in a few crucial ways. As serotonin and dopamine often balance each other out, if serotonin is too high, dopamine levels will be low. Emotional blunting and apathy result. It’s hard to go out and chase down a guy when your “Go get ’em, tiger!” neurochemical is lacking. Also, there’s less chance of your getting obsessive and fixated on one preferred partner when you are taking a medicine meant to treat OCD. If high dopamine and low serotonin drive the rewarding and obsessive nature of falling in love, being on an SSRI, with its resultant low dopamine and high serotonin levels, won’t drive the behavior. Female rats treated chronically with SSRIs reduce the amount of time they spend near males. Sex researchers are currently conducting studies showing that women on SSRIs rate men as less attractive and spend less time poring over images of their faces than women who aren’t on SSRIs, being “less likely to find those of their chosen sex physically attractive or desirable as a potential romantic or sexual partner.” Just as I recommend my patients get off oral contraceptives when mate shopping, there are reasons to slowly taper off antidepressants as well. If being on SSRIs means you already feel satiated and don’t even look twice at a guy, it’s going to be hard to move forward from attraction and infatuation to attachment.
Falling in love and choosing a mate rely on sexual attraction and sexual energy. If libido is lowered and sexual response is muted by an SSRI, it seems obvious that this will have a negative impact on the entire process. The neural systems associated with attachment and pair bonding also rely on orgasm and its resulting surge of oxytocin. Because SSRIs make orgasm much more difficult, they jeopardize this major trigger. One way that a woman can judge a potential partner is by how much time and attention he’s putting toward her pleasure. “Scientists think the fickle female orgasm may have evolved to help women distinguish Mr. Right from Mr. Wrong.” A man who can pay extra time and attention to a woman’s needs may also be a better father and more willing to share what he has (a dad and not a cad). Perhaps unconsciously, a woman may use her ability to climax with a certain partner to help her decide whether he is the one for her and her future children, or not so much. If it’s nearly impossible for her to be aroused all the way to orgasm because of her SSRI, then she can’t make use of this measuring device.
Lust
From an evolutionary perspective, you could say lust is practice for love. Learning to flirt to attract a mate, and practicing what to do when you find a potential partner, need to be finessed repeatedly over time. The chemistry of lust and attraction are similar, but not the same. Testosterone makes us horny, dopamine keeps us moving forward, and oxytocin frees us up from the fear of strangers so we can shed our clothes and get close. But with lust, a biological drive for sexual gratification, it’s more about testosterone and less about oxytocin.
Estrogen
