During mental health month it makes sense for us to focus on the relationship between depression and insomnia. Sleep difficulties are present in over 70% of patients who are diagnosed with depression and questions about sleep form part of every screening questionnaire for depression as well. Key for the definition of insomnia is difficulty obtaining sufficient sleep either due to difficulty in falling asleep or waking during the night including at the very end of the night and difficulty in going back to sleep. Daytime symptoms of fatigue and poor focus and concentration difficulties are common and important.
Many patients are then treated for depression and mood improves significantly once the correct medication has been used for a few months. There is an expectation that as depression improves the insomnia will disappear and for many people that is the case. For many, however, the insomnia remains and this causes confusion and often a hunt for better management of the depression. There are, however, many different causes for insomnia which should be investigated if sleep difficulties continue.
Causes of insomnia can include the 2 big sleep disorders – restless legs syndrome (RLS) and obstructive sleep apnea. The urge to move the legs at night that defines RLS may make it difficult to fall asleep while obstructive sleep apnea may result in night time awakenings often with a sense of anxiety. Both disorders are also common – 10% of the population for RLS and 23% for obstructive sleep apnea. Both disorders also become more common with increasing age. When we add circadian rhythm disorders – particularly delayed sleep phase syndrome – where the whole sleep period is delayed leading to lack of sleepiness until 2 or 3:00 – many patients with insomnia are likely to have a cause other than depression.
The most common cause of insomnia is a sleeping difficulty that remains after a clear cause for insomnia resolves. Any type of psychological stress – a death in the family, divorce – or physical stress – onset of a painful medical disorder or depression / anxiety – or even too much travelling across time zones can cause insomnia. This type of insomnia is referred to as short-term insomnia and in most people their sleep comes back when the stress resolves. In about 1/4 of people the insomnia remains but changes with increasing anxiety about sleep and changes in time spent in bed maintaining the insomnia without any obvious cause. Increasing anxiety and obsessive thinking about sleep makes the relaxation needed to fall asleep much more difficult. People battling to sleep often decide to go to bed earlier and wake up later to allow themselves more time to sleep. This approach does not work and leaves the sufferer lying in bed for hours trying to force the sleep process. Lying in bed for more than 15 minutes trying to sleep is likely to backfire – thinking gets more rushed (the racing mind), upsetting, catastrophic and ruminating (thinking the same thoughts over and over) – ensuring that wakefulness will continue.
While sleeping tablets are often used in this latter situation the solution lies in cognitive behavioural therapy for insomnia (CBT-I). Shortening the duration of sleep to the amount needed (rather than wanted) and getting up after failing to fall asleep after 15 minutes of trying often result in improved sleep within 2 weeks. Learning relaxation techniques, the personal biology of sleep and taking a sleep diary to monitor progress are also important components. With medical guidance better more natural sleep is possible within a month.
Overall, with many different causes for insomnia, failure to sleep well after treatment for depression does not necessarily mean failure of depressive medication but a possible independent cause for the insomnia. All these other causes of insomnia can be correctly diagnosed and treated with the correct medical approach.
