Studies have also tried to assess how many people suffer from sleep problems. Statistics vary but one study on mental health showed that insomnia concerned more people than other mental health problems including irritability and depression. This suggests that people are increasingly dissatisfied with the quality of their sleep and are aware of how it affects how they feel.There is also a growing interest is what makes us happy and content. The demand for courses and therapies that help increase a sense of 'wellness' and fulfilment suggests that many people are looking outside the material world for a sense of purpose.