Not everyone believes that Cortisol or serotonin holds the chemical answers to depression. There is a new theory, admittedly very much in its infancy, that the immune system could be involved. The idea is that people with problems with the immune system respond in one of two ways – either they develop an auto-immune disease or they become depressed. Women are more prone to both of these conditions. It is even possible that drugs like SSRIs are acting not only on serotonin but on the immune system and the Cortisol system in addition, which could explain why the drugs take several weeks to have an effect.
Again, these chemical changes in the brain could sometimes be a response to the outside world, rather than the brain spontaneously malfunctioning by itself. It’s arguable that we should no longer consider the physiological and the social to be separate. They affect each other, which would explain why drug treatments and talking therapies – which couldn’t be more different from each other – can both relieve depression.
the mystery of tears
Two years before her parents’ house burned down Julia was on holiday in Brisbane with her mother, who was recovering from cancer. Julia had recently called off her wedding and still felt desperately sad, but not wanting to add to her mother’s troubles she put on a brave face and tried to enjoy the holiday. Night-time provided the chance to cry. Once her mother was asleep she lay in the next bed weeping silently. Two weeks into the holiday her mother asked her why she was crying so often, admitting that she had listened to her sobbing every single night and didn’t want to be protected from Julia’s sadness just because she was ill.
Julia was grieving for the loss of the future she’d imagined for herself and was keen not to add to another person’s distress by discussing it. These responses both make sense. What is stranger is that a clear liquid should fall out of her eyes because she’s unhappy. It’s easy to see how tears wash out your eye and protect the surface from a sharp speck of dust or an eyelash, but why do we cry when we’re upset? In physical terms a bout of sobbing blocks the nose, irritates the eyes, puffs up the face and makes the head ache, yet sometimes we can’t help but weep.
A group of volunteers file into a makeshift cinema in a lecture theatre at the St Paul-Ramsey Medical Center in Minnesota, USA. They sit and watch a film about some children who are caring for their dying mother, only a year after their father died. It’s a film which openly manipulates the emotions. The phrase ‘tugging at the heart strings’ could have been invented for it. After they’ve lost both parents the children stand in a line in the snow while the eldest boy bravely declares that he will look after his young brothers and sisters. Meanwhile the heartless elders of the town just want rid of the lot of them. The volunteers watching the film have never met. They sit in silence wearing special goggles which have miniature buckets suspended beneath the eye-pieces. The reason they are here is to provide tears.
After years spent studying crying Professor William Frey has found that this is the easiest way to make tears come forth. Unfortunately the special glasses didn’t work because tears escaped down the criers’ cheeks. In the end he found it was easiest to have people collect their own tears in tiny test tubes. He experimented with different films and seating arrangements, eventually concluding that spacing was the key. When people are close to a stranger they hold back the tears.
Professor Frey went to all this trouble because he wanted to know whether tears of sadness contained different chemicals from the tears we cry when our eyes water due to soreness or irritation (known as irritant tears). He was drawn to the topic because he himself hadn’t cried since he was a boy and felt he might be missing out. Studies have shown that, like Professor Frey, some people don’t cry at all in a month, while it’s been found that others cry on up to twenty-nine days of the month. There are of course social rules prescribing when it is and isn’t appropriate to cry, particularly when it comes to boys. When my father was in pain in hospital after a tonsillectomy at the age of four, a nurse told him that boys don’t cry and that if he did people would think he was a girl. In fact despite this kind of social pressure, boys cry just as often as girls until the age of twelve, but by adulthood women are crying four times as often as men. Teenage girls are no more depressed than boys which has led to suggestions that the sudden difference in their crying frequency from the age of thirteen might be caused by the increase in girls in the hormones oestrogen and prolactin. However, studies on crying during pregnancy and pre-menstrual crying have been inconclusive, making hormonal explanations tricky. Of course it’s been assumed that the teenage boys are behaving normally by crying rarely while the behaviour of teenage girls needs some explanation, hence the hormonal theories. If you turn this idea on its head, perhaps there’s something about puberty that stops boys crying. Is it possible that increased levels of testosterone somehow block the crying response? When small mammals were given testosterone injections they vocalised less. It is also the case that as men get older they begin to cry often once again, just as their testosterone levels drop. Alternatively maybe they start holding back the tears when they reach adolescence for fear of someone seeing them and by the time they reach old age they simply worry less about a witness to their crying.
Weeping rates also vary from culture to culture. A researcher, Marleen Becht, spent three years collecting data from twenty-nine countries. She found that both men and women from the United States cried the most often, while Bulgarian men and Icelandic and Romanian women cried the least. It’s hard to know exactly what to make of that. For a start in some countries only thirty individuals were asked, which can’t tell you much about the habits of an entire nation. Moreover, these comparisons are based on each person’s own estimate of the number of times they had cried in the last four weeks. Cultural attitudes towards crying might influence the amount of crying to which people are prepared to confess. Having said this, when I visited Iceland I couldn’t help thinking about the rarity of tears there and found myself watching to see if I could spot any moist eyes. Disappointingly the guide didn’t burst into tears at the sight of a beautiful, white, double waterfall, but to be fair, he probably visited it every day.
Research also tells us that the most likely time for crying is between 7pm and 9pm. This isn’t surprising; it might be the first time all day that a person has had any privacy and the factors likely to induce crying are all present – tiredness, sad TV programmes and family arguments. There’s also the possibility that the circadian rhythms which govern our sleep cycle play a part. Babies cry the most in the evenings, why not adults?
Tears of sorrow seem to be unique to humans, although there are anecdotal reports from Darwin of Indian elephants weeping when they are bound and immobilised. Professor Frey wrote to lots of zoologists and animal trainers to see whether they had witnessed such events. Most said that they had not but he has received anecdotal reports from pet owners who report seeing all sorts of animals shedding tears – from pigs to Chihuahuas. Diane Fossey, who famously spent years studying mountain gorillas, described witnessing Coco, a three-year-old captive gorilla, looking out of the window and shedding actual tears. I was tempted to write ‘looking out of the window longingly’, but that would have been my interpretation of the gorilla’s emotions and therein lies the problem. The trouble with these reports of weeping animals is the all too human tendency to anthropomorphise. It’s hard to distinguish what an animal is feeling from the way we imagine we would feel in the same situation.
zeis, manz and the crypts of henle
In humans, at least, we do understand something of the chemical constituents of tears. They were first analysed back in 1791 and were found to consist of salt, mucus and water. Most of the watery part comes from the lachrymal glands which are at the top outer edge of each eye. This liquid is sandwiched between inner and outer layers which come from glands with such wonderful names as Zeis, Moll, Manz and the crypts of Henle. The oily top layer stops the liquid from evaporating too fast. When we blink tears slide across the surface of the eye towards the inner corner, but if we cry the tears collect in triangular lakes until they overflow, slipping over the edge of the eyelid and down the cheek.
During the first two or three months of life newborn babies