I tried the Sleepio programme a couple of years ago. A lot of it is basic sleep hygiene stuff, but it was helpful in reducing my distress at not sleeping. Eg I used to worry that I was still awake and “I’ve got to get up in X hours”. Now I don’t worry about how little sleep I get because I know that I will manage the next day, but that could be partly experience of knowing now that I can somehow survive on 0-3hours sleep a night.
In terms of increasing my sleep quality or duration, it did not change that. But I do believe that there is something fundamentally wrong with my body clock/sleep, rather than anything psychological (though that can play a role and the CBT-I stuff does help with that when it occurs for me), because I just do not feel sleepy tired until everyone starts to wake up. I choose not to use sleep meds though because of inefficacy, or too sedating - personally I’d rather sleep 0-3 hours a night than sleep 12+ and be a zombie whilst awake, but that’s just my personal preference.
All the best
*Willow*