Serotonin is a hormone that regulates mood; it can also help to manage obsessive thinking. When we fall in love, the serotonin levels in our body fall in a way that mimics the way they are shown to be lowered in some individuals with Obsessive Compulsive Disorder. Individuals with low levels of serotonin are more likely to engage in sexual behavior which then again releases dopamine and oxytocin. As you can see, the biochemicals involved all interact with each other to contribute to this vicious cycle.
This is why narcissistic abusers can dominate our brains in the early idealization phases of the relationship with their love-bombing, the excessive adoration we receive in the beginning. Imagine how this effect is compounded in the devaluation and discard phases, when, we are made to think about our narcissistic partner 24/7 due to their covert put-downs, their silent treatments, their stonewalling, their infidelity, and their sudden disappearances. We become obsessed with them not just through love, but again, through fear, through anxiety and rumination.
5. Trauma bonding.
All of these jolts of fear and anxiety in the face of danger can reenact past traumas and create trauma bonding. Trauma bonding occurs after intense, emotional experiences with our abusers and tethers us to them, creating subconscious patterns of attachment that are very difficult to detach from. It is part of the phenomenon known as Stockholm Syndrome, in which victims of hostage become attached to their perpetrators and even defend their captors.
Although survivors of narcissistic abuse come from many different backgrounds and anyone can be a victim of narcissistic abuse, trauma bonding is even more significant for those who grow up in violent or emotionally abusive homes, and/or have had a narcissistic parent in addition to their most recent experiences with trauma and abuse.