Why does my body jerk just as I fall asleep? Ask GP DR MARTIN SCURR

Sometimes when I fall asleep I have episodes that I can only describe as a ‘zap’ – which wakes me up. I have regular eye tests and nothing came out, but I’m worried. I am 71 and otherwise in good health.

Edith Tinsley, Lancashire.

Dr. Martin Scurr replies: What you have described is a common phenomenon known as a hypnagogic hallucination. These are vivid but transient hallucinations that occur between wakefulness and complete sleep (known as the hypnagogic sleep state).

Generally, those affected experience something visual – often a moving image (for example, patterns) or vivid images of faces or scenes, but some people hear background noise. Others may also have a feeling like falling.

These hallucinations can be caused by stress, sleep deprivation, caffeine, or various medications, including antidepressants (e.g. fluoxetine, amitriptyline), possibly due to their effect on the nerve pathways in the brain. More rarely, these episodes are related to narcolepsy – a condition in which people suddenly fall asleep during the day.

They are not the same as nightmares, which occur when a person is completely asleep.

Transient hallucinations are very common, affecting up to 70 percent of people at least once and are not associated with any disorder. I hope you will find this explanation reassuring.

I have been diagnosed with fibroids, a thickening of the uterus and a small hernia. Consultants have told me that they will not remove the fibroids because they are less than 5 cm in size. I constantly suffer from constipation, bloating and a swollen stomach; It feels like I’m carrying a football with me. I also have constant pain, similar to menstrual pain. I’m 69 and don’t want to put up with this for the rest of my life.

Andrea Ford Newtown, Powys.

Dr. Martin Scurr replies: Uterine fibroids are non-cancerous growths that occur in the uterus (womb) or in the uterine wall.

There could be one, or several. I have seen them as big as a tennis ball and sometimes as big as a rugby ball. It is not known why they develop, although it is thought to be a combination of genetics and hormonal factors.

They arise during a woman’s reproductive years – estrogen fuels their growth – and are made up of smooth muscle cells and fibrous tissue. Once estrogen levels drop, postmenopausal fibroids stop growing and slowly shrink. They never disappear completely and can also harden due to limescale.

Fibroids cause symptoms in women who are menstruating (such as heavy periods), but not in postmenopausal women.

So the question for you is to determine the cause of your constipation and bloating. One possibility is a form of irritable bowel syndrome: this cannot be diagnosed without ruling out other possible causes.

The first step should be blood tests to check for anemia and to rule out an abnormal blood count, also checking for inflammatory markers.

I would also expect that you will be offered a faecal immunochemical test, which is a home test where you send a stool sample to be tested for traces of blood – and that your GP will arrange a colonoscopy to inspect the lining of the intestine.

If you are taking hormone replacement therapy (although I suspect so, given your age), it is possible that the estrogen is stimulating the growth of the fibroids. Ask your doctor for further examination.

IN MY OPINION: What is the real cause of the increase in ADHD?

You couldn’t have missed the rise of ADHD (Attention Deficit Hyperactivity Disorder). Before 1990 I had never heard of the term, but in the year 2000 we had guidelines on diagnosis and treatment from the National Institute for Health and Care Excellence.

Now we regularly read about celebrities who have been diagnosed with this complex condition in adulthood.

Left untreated, a child with ADHD can experience significant educational and social problems and have a high likelihood of academic failure, as well as difficulty finding work in adult life.

The question I would like to ask, without doubting the severity of its impact, is whether ADHD is a disease or an extreme human behavior, at one end of the spectrum of what is acceptable.

The right dose of the drug used to treat children with ADHD – methylphenidate (brand name Ritalin) – allows them to behave normally almost immediately. To me, the speed of the response speaks volumes about the fact that this is not a physiological problem.

And I wonder if one day we will have a nice form of imaging that will show a neurological lesion that is the cause of this condition. It remains to be seen.