by Dan Schwarzman
What is love, and why does it exist? Chemical similarities have been found linking love to OCD and depression. Anthropologist Helen Fisher PhD of Rutgers University has been doing research on love, which she has divided into three chemically separate states. Fisher says that lust is driven by androgens and estrogen, while romantic love, characterized by intensely emotional mood swings and obsessive craving, is driven by high dopamine and norepinephrine levels, along with low serotonin. The third state, of stable attachment, is driven by the hormones oxytocin and vasopressin.
An evolutionary anthropologist, Fisher explains the evolutionary value of these three states. According to evolutionary theory, adaptations show up in species if they lead to increased survival and reproduction. Fisher says that lust evolved as a mechanism for people to be interested on a basic level in reproduction with others, while romantic love developed to focus one’s mating energy on just one individual. Stable attachment works to tolerate this individual long enough to raise children as a team. The obsessive energy output of being in love might seem illogical in the context of evolutionary theory, especially since love is often not reciprocated, but this ability to forgo short term efficiency in favor of greater long term reproductive success makes sense as an important adaptation for the continuation of the human race.
Interestingly, the low serotonin levels found in romantic love are similar to the brain states of people with OCD. One study compared the brains of 20 subjects who were in love, 20 subjects with untreated OCD, and 20 control subjects. The study found that serotonin levels in the lovebirds and those with OCD were both unusually low compared to the control group (Marazziti, Akiskal, Rossi, & Cassano 1999). A plausible explanation is that OCD and love are similarly obsessive, driving urges, and that serotonin is somehow involved with this kind of focused obsessiveness in the brain. Dr. Fisher’s 2002 study found that some infatuated subjects reported thinking about loved ones 95% of the day.
Low serotonin levels are also linked with depression, including SAD, or Seasonal Affective Disorder. A recent study by researchers at McGill University studied the effects of light and lack of light on people’s moods and social interaction, and found that increased serotonin associated with more light causes healthy people to become more socially agreeable (Rot, Moskowitz & Young, 2008). Scientists have picked up on the connection between depression and low serotonin, and most common antidepressant drugs serve to raise serotonin levels in the body.
A frequent side effect of antidepressants is problems with sex and love life, including lack of interest in pursuing potential mates. Studies have put the percentage of patients who complain of experiencing sexual side effects from antidepressants at around 30-40%, but when directly asked whether they are experiencing any issues, up to 73% of patients admit to sexual problems, sometimes unaware that there is a connection to the antidepressants they are taking. It is understandably more difficult to measure blunted romantic feelings than more physical sexual symptoms, such as decreased genital sensitivity, but connections have been drawn from antidepressants to both physical and mental sexual problems.
What does all this mean? Love is an obsessive compulsion that probably evolved as a means for individuals to focus on specific other individuals with enough energy to ensure reproductive success, and possibly long term attachment, which would lead to better chances of survival for offspring. Because love is characterized by obsessive thoughts similar to depression and OCD, it begins to make sense only as an evolutionary strategy. Love is not chemically similar in some ways to stable happiness, but instead includes seemingly inefficient use of energy, as well as frequent disappointment. When seen as an evolutionary strategy to ensure production of offspring, love finally becomes a bit more logical, even if we remain ever susceptible to its emotional highs and lows.
Brink, S. (2007, July 30). Are antidepressants taking the edge off love? – Sure, we know about the sexual side effects of SSRIs. But researchers now wonder if that’s the only aspect of romance the drugs can influence. Los Angeles Times, pp. F8.
Fisher, H., Aron, A., Mashek, D., Strong, G., Li, H., & Brown, L. (2002). Defining the Brain Systems of Lust, Romantic Attraction and Attachment. . Archives of Sexual Behavior, 5, 413-9.
Marazziti, D., Akiskal, H., Rossi, A., & Cassano, G. (1999). Alteration of the platelet serotonin transporter in romantic love. Psychological Medicine, 29(3), 741-745. Retrieved March 3, 2009, from http://pt.wkhealth.com/pt/re/pgme/abstract.00006826-19990500000024.htm;jsessionid=JwMWBLvJlQYMfp4ypLwTlnJ3Z2GQ5Brzpt5Jf3GfGBdWTL9HGcgt!751744069!181195628!8091!-1
Rot, M. a., Moskowitz, D., & Young, S. (2008). Exposure to bright light is associated with positive social interaction and good mood over short time periods: A naturalistic study in mildly seasonal people. Journal of Psychiatric Research, 42(4), 311-319. Retrieved March 4, 2009, from http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T8T-4MYFG4R-2&_user=557743&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000028458&_version=1&_urlVersion=0&_userid=557743&md5=3eb48b53d31d7b07088be909fcfecdcc
Sher, L. (2003). Bright light, serotonin turnover, and psychological well-being. Canadian Journal of Psychiatry, 48(7), 499.
Sexual Side Effects Of Antidepressants Common, But Still Seriously Underestimated By Physicians. (n.d.). Retrieved March 27, 2009, from concernedcounseling.com/Communities/Depression/treatment/antidepressants/sexual_side_effects_2.asp