'Love in a pill': Is it possible?
In order to understand whether pharmacy can mimic the elation experienced when in romantic love, it is first necessary to fully elucidate the primary neurochemical mechanisms involved in mediating love.
Love is a highly complex emotion with variable definitions. Yet, I would argue that one major constituent of love is the neurotransmitter dopamine, and the reward-motivation system in the brain. A pioneering study by Fisher (2005) has revealed active engagement of the Ventral Tegmental Area and Nucleus Accumbens, major components of the dopaminergic circuit, in emotions of romantic love as opposed to neutral thoughts.
At the same time, however, the hormones oxytocin has correlated to trust and human sensitivity that factors in producing love; Moreover, oxytocin has shown to inhibit amygdala activity (the brain region responsible for emotion), and thus decrease anxiety levels in those experiencing love. Other chemicals involved include vasopressin, and neurotransmitter serotonin (responsible for pleasure). As such, antagonists (inhibitors) of oxytocin or vasopressin receptors have shown to consequently inhibit mating in animal studies , suggesting receptors to play an important role in neurotransmitter processing during emotion as well. Endorphins, the body’s natural ‘painkillers’, are further connected to feelings associated with love. Ironically, subjects in love also displayed higher concentrations of cortisol, known to contribute to stress. With regards to gonadic (sex) hormones, testosterone levels were lower in men, and higher in women, in the early stages of love.
Other brain regions involved include the ventral pallidum (as it largely consists of the V1a vasopressin receptors), anterior cingulate cortex, mid-insular cortex, and caudate nucleus (all, broadly, responsible for emotion). These regions also show large numbers of oxytocin (OT) receptors. Moreover, deactivation in the prefrontal cortex (responsible for planning and judgement).
Thus, attributing love to simply one ‘chemical reaction in the brain’ would be rather an oversimplification. A large body of data points to a wide interaction between hormones, neurotransmitters, receptors, and brain regions to instigate romantic feelings. Moreover, these interactions differ with time, and the kind of love (i.e, intense romantic love, maternal love, or lust). As such, it would appear difficult to pinpoint a specific pill as to induce the pleasurable feelings associated with love; however, in theory it is a very interesting concept.
My personal take on this would be that if the pill comprises of a cocktail of chemicals closely resembling dopamine, serotonin, oxytocin, and vasopressin in structure, and that are ensured to be uptaken by the limbic system (i.e, ventral tegmental area and other regions involved in emotion), then the feelings achieved would be highly similar to those of love. Nevertheless, there is the possibility of the pill resulting in being simply another ‘addictive drug’; Here, I’d argue that including oxytocin and vasopressin receptor agonists would be essential in ensuring emotions of love rather than pure pleasure.
Essentially, agonists work by minimicking the structure of the neurotransmitter, thus furthering neural activation, which correlates to higher neurotransmitter-specific function:
Examples of dopamine agonists would include pramipexole, or ropinirole, serotonin agonists include Zolmitriptan, while oxytocin/vasopressin agonists include F180, carbetocin, dDAVP and terlipressin.
Ethical considerations would include their differential effect on other bodily functions and also between males/females. Clearly altering the neurochemistry of the brain will, in some manner, disrupt base-level homeostasis, possibly altering the number of neurotransmitters in the brain and leading to physical dependencies. Moreover, as these chemicals play a role in different functions (e.g. oxytocin is also responsible for uterine contraction, serotonin also regulates sleep and memory), altering their prevalence in the brain could lead to unwanted side-effects. As such, if such a drug were to develop, it would have to undergo thorough animal testing and careful clinical trials in various populations (different races, ages, genders etc.), before being released into the market. One must also be wary to the emergent effects of cross-interactions between receptor-specific drugs.