Anxiety & Depression
We’re all aware of how a single night of poor sleep can affect us the next day, not least our mood and our ability to think straight.
Non REM sleep is important for sorting the wheat from the chaff of the previous day’s experiences and memories – think of it as tidying your desk at the end of the day. Those thoughts or memories that are of little value to you are put in the bin while those that are meaningful are kept in the in-tray.
These meaningful experiences are then emotionally resolved in REM sleep. They may not all be pleasant, so REM sleep offers a safe mental environment in which we can come to terms with those things that have caused anxiety. After a proper night’s sleep, we are likely to wake feeling the previous day’s problems are less of a burden and we feel sufficiently clear-headed to be able to take on new challenges.
If, however, sleep has been interrupted, the process is incomplete and we wake feeling apprehensive and unprepared for the new day.
For those with anxiety and depression, this can reinforce and perpetuate the belief that the world is a more negative, worrying or threatening place than it really is.
The link between anxiety and depression with insomnia has been widely documented. However, an interesting American study [Michael Perliss] evaluated the effects of treating the insomnia of 30 people who had also previously been diagnosed with major depressive disorder. During the study, there was no treatment offered for the major depressive disorder.
At the end of the treatment process, 50% of the participants had remitted their MDD symtoms and this was maintained at 3 months.
Note: this study has not been published in the UK because of differing procedural standards. The study does not absolutely clarify whether treating the insomnia resolved the MDD or if it was in fact the other way round. UK standards also first require treatment of the presenting symptom (MDD).
If the study is taken at face value only, then these results make interesting reading. Another well recognised study by Manber et al (2008) of the benefits of treating insomnia when comorbid with depression can be found here.