Never heard of sleep apnea and nasal strips before, thanks! I'll try them out. Sleep quality can be influenced by lots of factors, one of them is depression and anxiety. For example, on Bipolar II disorder Wikipedia page it states that type I bipolars sleep less, while type II bipolars sleep much more. Another example is that many depression scales such as Beck Depression Inventory actually consider lack of sleep or oversleeping as one symptom of depression among others. So, counter-intuitively, some people, who have sleep problems, might benefit from reading Feeling Good :).