Greetings Earthlings! 🙂
This week I’d like to talk about the role that hormones (or horror-mones as my younger cousin used to call them) and fluctuations in hormone levels may play in autism.
So first off the basics, what exactly is a hormone?
We’ve all heard of them, but not all of us are aware of how they work.
Hormones are powerful biochemical messengers that travel through the blood in the body influencing a number of bodily changes and functions such as growth, mood, metabolism, puberty and reproduction to name but a few. Secreted by the endocrine glands of the body (e.g. adrenal glands, thyroid, pancreas etc.), it only takes a small amount of hormone to trigger large changes in the body, so fluctuations in normal hormone levels can have serious consequences for bodily functions.
So what impact do hormone changes have for autists?
Research suggests that a number of hormonal imbalances can contribute to autistic behaviours. The primary hormones thought to contribute to autism are oxytocin and vasopressin- also referred to as the “love” or “social” hormones. These hormones are involved in social bonding, trust, sexual behaviours and processing of sensory information. Studies have revealed that autists have lower levels of both of these hormones, and that treatments designed to increase these hormones may help improve social behaviours.
Most recently, new evidence suggests that growth hormone and the digestive hormone ghrelin may contribute to autism. A recent study showed that children with autism have lower levels of these hormones compared with their neurotypical peers. Ghrelin has a wide range of physiological functions such as stimulating the release of growth hormone, memory and learning, the formation of new brain synapses between neurons (i.e biochemical junctions joining one brain cell to the next) and it is involved in triggering satiety after meals (guess that explains why I’m always hungry 😛 ).
As many of these functions are disrupted in autism, low levels of these hormones likely contribute to their pathology. Moreover, ghrelin is thought to have a protective effect against reactive oxygen species in the brain which are also thought to contribute to autism (as I’ve discussed in previous posts) so reduced ghrelin levels could reduce the brains protection against these chemicals.
Hormone fluctuations are also thought to cause sleep issues for autists. The amino acid tryptophan is needed for the body to produce melatonin (aka the hormone that controls sleep and wakefulness), an amino acid which research has shown can be either higher or lower than normal in people with autism. Ordinarily melatonin is released in response to darkness (to induce sleep) with levels dropping during daylight hours (to keep us awake). However, studies have shown the opposite in some autists, where higher levels of melatonin are released during the daytime and lower levels at night- which certainly explains why I often have the urge to nap throughout the day 😛
In addition to these, higher stress hormone levels are thought to be the driving force behind a number of autistic behaviours such as meltdowns, shutdowns and issues with anxiety. As I’ve discussed in a number of previous posts, stress hormones such as cortisol and adrenaline are released in response to stressful situations from the hypothalamic–pituitary–adrenal axis or HPA axis. This is a complex interconnecting network that comprises the hypothalamus, the pituitary gland and the adrenal gland (i.e. HPA) to control our response to stress- a network that is hyperactive in autists. Following exposure to a stressful situation, stress hormone levels should return to normal, however, research has shown that stress hormone levels tend to persist in autists, which can make us more susceptible to stress related outbursts and meltdowns. In other words, we’re constantly living in a state of fight or flight. Long term activation of the stress system can lead to a number of health problems such as poor mental health, weight gain, sleep issues, digestive and cardiovascular problems to name but a few- many of which are regularly comorbid with autism.
Sex hormones are also thought to contribute to the development of autism. Research in recent years has indicated that exposure to higher levels of testosterone and/or oestrogen in the womb may predispose developing babies to autism- this is known as the sex-steroid theory of autism. It’s thought that these elevated hormone levels likely interact with genetic factors that may affect the developing brain. There is a particular trend among women who suffer from polycystic ovarian syndrome (PCOS) as the ovaries produce abnormal amounts of testosterone.
Moreover as I’ve discussed in previous posts, hormone imbalances are also thought to contribute to changes in behaviour in autistic women due to fluctuating hormone levels at different points in their menstrual cycle. In addition, behavioural changes are also associated with autistic women going through the menopause.
With the interplay of all these different hormone fluctuations, it’s no wonder our brains are a little muddled trying to cope with the constant change (as if we don’t find change hard enough! 😛 )
Hope you enjoyed this post dear Earthlings!
Have a lovely weekend! 🙂