Helping your children means you need to help yourself first. Please check out The Limbic System and The Daily Program. You can practice the breathing and Qi-Gong with your children. 

Here is a link to a series of videos that help manage small Children in Distress. 

http://anxietybc.ca

http://keltymentalhealth.ca

http://anxietycanada.com/MindShift-CBT

http://foundrybc.ca

Resources for ADHD

Complex trauma and PTSD in children

There are also books – Taking charge of ADHD by Russel Barkley

Recommended books for children:

Books for parents with children with anxiety.

Taking charge of ADHD by Russel Barkley

Freeing your child from OCD by Tamar Chansky

There are many resources on this website to help for anxiety and stress. Step 2 is very important. Also have a look at Stress Anxiety and PTSD and Complex PTSD. 

Medications can help depression. They have a small risk of increased suicide thoughts, but children who really need antidepressants are safer taking them than not taking them. A number of years ago when we discovered this risk of suicidal thoughts with anti-depressants, we stopped using them in children and for the next couple of years, the rates of completed suicides skyrocketed all over the world and we went back to using them. 

Medications.