Married people live longer, but more surprising is that for some groups, especially widows, the mortality gap between married and unmarried is widening.
Research undertaken at Michigan State University between 1986 and 2000 found that in spite of falling mortality rates for most illnesses there was a general widening in the mortality gap between the married and unmarried. It seems as though those people who say "till death do us part" and live up to it actually live longer.
Quantity is one thing, but what about quality? In other words, how do the married fare against the unmarried in terms of health and happiness?
The institution of marriage is a key factor in understanding human well-being. Over the last few decades health researchers and social scientists have repeatedly prodded and probed marriage in a fruitful attempt to understand the ways in which it might contribute to health, and prevent illness.
One of the most consistent findings to emerge from this body of research is that married people (men and women) have significantly lower rates of depression than their divorced, widowed or never-married counterparts. In most studies, people in first marriages even have lower rates of depression than those who are remarried, or cohabiting.
There are generally three, arguably complimentary, explanations for the relationship between marriage and lower levels of depression.
The first sounds a little Darwinian, and is known as the "social selection hypothesis". The argument here is that people who are less depressed to begin with are more likely to be selected for marriage. Think about it - who goes looking for a morbidly morose mate?
The second theory is that the relationship between marriage and emotional well-being is spurious, and that some undetected factor is promoting both. An example might be socioeconomic status, such as being wealthy and coming from a respected family.
However, many studies have controlled for obvious factors like age, income and social status, and even after taking these other factors into consideration the emotional benefit of being married persists.
The third explanation, known as the "social causation hypothesis", proposes an inverse causal relationship between marital status and depressive symptoms. The idea is that marriage acts in some way to promote well-being, protecting us from the slings of outrageous fortune.
This social causation idea has recently been explored longitudinally by researchers within the department of sociology and gerontology at the University of Kansas. Previous research had relied on snapshots; this longitudinal study followed 9,507 people over a five year period.
One of the questions this research aimed to answer was, does being married provide a cumulative advantage in terms of well-being?
As in most of the previous research, people who were re-married, divorced or separated, widowed or never married at all were found to have significantly higher depression scores than men and women in their first marriages.
These findings held true across different age groups studied, but more significantly, cumulative effects were also found. Divorced or separated individuals showed increasing patterns of depressive symptoms over time, whereas those in first marriages showed decreasing patterns of depressive symptoms over the same period.
A recent study in the UAE has looked at this relationship, specifically focusing on Arab women attending primary healthcare clinics in Sharjah. As in the previous research, there were significantly higher rates of depression among single, widowed and divorced women than among married women. There were no significant differences between the women in polygamous and monogamous marriages.
The upwardly ascending rates of divorce and spinsterhood in many parts of the world deserve intensified research. The same applies to the rapidly increasing incidence of depression and suicide, especially among young people. The much en vogue concept of sustainability may be fruitfully expanded to the psycho-social domain.
There is little point having a planet to live on, if we have forgotten how to live together, or lost the will to live at all.
Justin Thomas is an assistant professor of psychology at Zayed University