Contrary to popular belief, an important paper published recently, suggested that Insomnia does not increase mortality risk. Nicole Lovato and Leon Lack at Flinders University conducted a review of studies that investigated the link between insomnia and mortality. The review considered data from 37 million participants and followed them up for an average of 11.6 years (of course, further research is needed with a longer follow-up period).
So how come there are so many seemingly conflicting conclusions on this issue of long term impact of insomnia? It’s enough to make anyone have a sleepless night getting to the bottom of it. To answer this it's important to understand that short sleep duration and insomnia are not the same thing.
One issue with the reporting of research is that short sleep duration and insomnia are terms that are used interchangeably.
Research on the impact of long term short sleep duration does indeed find links with poor health outcomes and mortality. Although objective short sleep duration is characteristic of some types of insomnia, research suggests that this may only be 40-50% of insomnia sufferers.
Insomnia isn't defined by how much sleep the person gets, a person with insomnia, may, on average, be sleeping very little or quite a lot. The typical pattern of insomnia is lots of variability night to night – for example, a poor night (or run of poor nights) being followed by a longer catch-up sleep. It is often the case that people with insomnia believe that they sleep less than they actually do. Studies suggest that people with insomnia sleep on average around 6+ hours per night which is above the risky range for short sleep duration.
Another issue which may have strengthened the belief that insomnia increases mortality risk is that the studies that have found an association between insomnia and mortality are headline grabbers and more likely to be reported on and shared.
This is not to say that Insomnia is a condition to be ignored, far from it. Insomnia reduces quality of life and productivity, increases health care usage, risk of depression, anxiety and diabetes.
Finally but importantly, Lovato and Lack found that while Insomnia did not increase mortality risk, that use of medicines designed to treat the condition did slightly increase mortality risk. Sleeping pills are only designed for short term use (a few weeks) and can cause problems if taken in the longer term.