Is sleep a form of ‘overnight therapy’?

Posted on January 10, 2012


"The Knight's Dream", 1655, by Antonio de Pereda (Wikipedia)

Dateline: 23 November 2011 // Posted by: Sinead Kearns

Source: Irish Independent, Daily Mail

Story: “Can dreaming really make all our worst memories fade away?”

Summary: This story was reported in various news outlets and it concerned researchers at the University of California in Berkeley including Els van der Helm and Mathew Walker. The report indicates how these researchers have claimed to have come across evidence to suggest that dreaming provides us with a form of overnight therapy that makes the bad memories from the previous day seem less stressful.  Allegedly, during the dream phase of sleep our brains can actively work through bad experiences to make us view them in a more positive way.

These researchers describe how this happens due to a sharp reduction of the stress hormone norepinephrine while in REM.  The news report states that the researchers concluded this following an experiment involving subjective reports from 35 adults. 150 emotional images were used in the study and an MRI scanner was used to measure participant’s brain activity. They indicated that their findings were some of the first insights into the emotional function of REM sleep.

Why is this PseudoNews? This material is scientifically questionable for a number of reasons. Firstly, everyone on earth has experienced some sort of distressing experience, a horrible experience that no amount of sleep could cure. We may have a terrible experience take for instance, the death of a loved one, a natural disaster, rape, a robbery, a violent attack, a house fire or even an argument with a close friend. These situations, as we all well know, take much longer (if ever) than one night’s sleep to overcome. So why do these news reports beg to differ?

“It is thought that a dip in stress hormones while we are dreaming allows the brain to safely work through bad experiences. As a result, when we wake up, things really do feel better.” (The Daily Mail)

If this ‘overnight therapy’ was really a breakthrough in dealing with bad memories it would have came to the fore long ago.  Dr. Brian Thompson quite rightly states that science is a slow, multi-stepped process filled with cautious claims. Ironically, he declares, nothing emerges victoriously overnight, which is what this report is suggesting.

The news reports and also the study itself seem to heavily promote and surround anecdotal evidence. For instance in the actual report by Walker and Els van der Helm (2009) their concluding line is:

“-when troubled, ‘get a good night’s sleep, and you’ll feel better in the morning.’”

This suggests nothing scientific, only the already widely credited idea that regular and healthy sleeping patterns help us to function throughout the day, but this does not suggest that dreaming can help fade away bad memories.

What features of pseudoscience are on show? The report lacks parsimony. The study by Walker and Els van der Helm was extremely tenuous in the sense that only 34 participants were involved and it was conducted over a twelve hour period. Therefore no firm conclusions should be drawn from it. There are too many unexplained elements in the study. Alternative explanations hold more parsimony for instance; it is possible that achieving a deep sleep rather than dreaming is responsible for the changes in brain activity.

There also seems to have been a lack of blinding. Blinding is an extremely important element in clinical trials, which was not present in this study. It is possible that the reactions of some people were affected by knowledge that they had slept, rather than the sleep itself. Therefore subject bias could well have been an issue in this study but was not controlled for.

The moral of the story: The moral of the story then, get a good night’s sleep tonight but don’t be fooled, whatever bad memories you have,  will more than likely still be there come morning despite what the media says!