Can listening to delta waves at night, or any brainwaves help with anxiety and depression?

Help (not cure): I'm so glad you used the word 'help' that I want to be as affirmative as possible. I've never heard of this Tx but it could have a useful placebo effect and many medical procedures take advantage of this. If there are no dangers and it will not deprive you of money needed for other things - see what it does. Remember that there are other options. It's NOT recognized as a Tx so be careful. Best!