Background Many young people have problems with mood, and most are not getting any help. We are now looking at different ways in which to help young people online with their health, mood and well-being. We have developed the MoodHwbappand website with young people and families/carers to support their mood and well-being. MoodHwb is for young people and for families, carers, friends and professionals - who would like to know more about low mood, anxiety, depression, and other health difficulties. It also has information on self-help, ways of staying well, and where to get help. There is amood diaryto help them to notice changes in how they are feeling. They can also set goalsand storelinks to helpful resources.It can be used in English or Welsh (as HwbHwyliau). Why are we doing this research? We are interested in how young people and parents/carers might use the MoodHwb app and website, compared to using a digital information pack for mood and well-being, along with any other help they are getting (e.g. school counselling). It is important to get feedback so that we know how to improve and test this programme further. If found to be effective, the programme could be made freely available in future. Who can take part? 1. Young people who: a. are between 13 and 19 years of age b. have had problems with their mood and well-being (e.g. feeling down or low in mood) c. have regular access to the internet. It does not matter whether they have other support (e.g. school counselling). However, we are looking for young people who are not under the care of secondary child and adolescent mental health services (CAMHS) and do not have severe mental health difficulties (apart from depression or anxiety). 2. Their parents and carers Who is organising the study? Doctors and researchers at Cardiff University and the University of Glasgow are organising the study. It is funded by the Welsh Government through Health and Care Research Wales / National Institute for Health Research. Further information For more information about MoodHwb and the study, and how to take part, visit: ncmh.info/digital-support-study/ and read the study information sheets.