Our fascination with dreams dates back centuries. Ancient
cultures such as the Egyptians and Greeks even had dedicated gods of dreams. In
the early 20th century, the founding father of psychoanalysis, Sigmund Freud,
suggested that dreams are a manifestation of our most secret and repressed
desires; and instead of living them in real life, we act them out in our
dreams. Recent research has shown, however, that there might be more to dreams
than just unfulfilled needs. In fact, dreams could be an indicator and
predictor of certain diseases.
Nightmares, for example, could be a sign of heart
conditions, migraine, sleep deprivation or a side effect of beta-blockers. Many
dreams could be an indication for either being too hot or cold during the
night, hormones, chronic pain, or coming off antidepressants.
Too much alcohol, an infection, the menopause or
anti-malaria pills could cause memorable or bizarre dreams. A fatty meal, too
much weight, stress or depression could give you dreams that wake you early;
and sexual dreams do not necessarily represent anything about a person’s sex
life, but could actually be triggered by creativity. Many pensioners reported
having increased sexual dreams, which could be caused by taking up new hobbies
during retirement.
Bashing about in your dreams, or dreams of attacks or wild
animals, could be an early warning sign for Alzheimer’s or Parkinson disease.
These dreams can be one of the first recognisable symptoms and can appear even
a decade before the actual onset of the disease.
Alzheimer’s is a neurodegenerative disease, in which
insoluble mutated protein (amyloid-β)clumps called plaques accumulate in the
spaces between nerve cells. Protein tangles can even build up in nerve cells,
thus hindering nerve cells to function properly.
Sleep disturbances, and in particular increased daytime
sleepiness, could be an early sign of Alzheimer’s, which could be caused by the
protein plaques. Researchers discovered that in mice the plaque concentration
peaked during wake times, but fell when mice were asleep. Depriving mice of
sleep increased the protein concentration dramatically. Once the plaques were
removed, their sleep pattern went back to normal. Daily fluctuations in the
concentration of the mutated protein were also found in humans.
It remains unclear whether the sleep disturbances lead to
Alzheimer’s, or if they are caused by it, but it is suspected that they might
reinforce each other. “Abnormal sleep in mid-life might cause protein
aggregation that starts the disease off,” Holtzman tells Nature “, and the
damage it causes may further disrupt sleep.” “Once we saw that amyloid-β was
going up and down with the sleep–wake cycle, the implications began to unfold,”
says Holtzman. These findings suggested that sleep disturbances might actually
precipitate plaque formation. And if a sleep deficit could increase the
concentration of soluble amyloid-β, says Holtzman, then sleep abnormalities in
earlier life may predispose people to Alzheimer’s.”
During an 8-hour sleep period, the brain goes through
different stages of electric activity in repeating cycles that change about
every 90 minutes. We spend about 20-25% of our sleep in the REM phase (rapid
eye movement), which is often associated with dreaming. During sleep, information
is downloaded from one brain region to another, so sleep is a crucial time for
learning and memory consolidation. It is now known that memory processing and
even dreaming are not confined to the REM phase. It might help us, however, to
deal with emotional processing of events that happened during the day. Research
has shown that the slow wave sleep phase is very important for memory
consolidation and learning, but it becomes shorter in the ageing brain. It
seems that an ageing or deteriorating brain, bad memory and bad sleep are
somehow connected.
Many factors can influence the sleeping and dreaming
pattern, we can control some, but others we cannot. Despite a lot progress in
research, our understanding of the brain and its functions remain partly
unclear. Until we have resolved the mystery of why we dream, what our dreams
mean, dreaming will certainly remain an enigma that will not cease to surprise
and entertain.
