I have read that anxiety can be due to a number of factors: poor socialisation, genetics, a stressful experience (even experiences in the womb), and many more factors…
It can only take one incident to make a dog start to display reactive behaviours.
For George, I think there is likely some genetic disposition towards anxiety given his nervous disposition from a young age.
Our VB and trainer mentioned that they are seeing more cavoodles at the moment (although that could be because there are more of them!).
I can pinpoint a couple of incidents which would likely have caused further fear (see Our story so far). There were probably others which I didn't recognise. I learned that your dog decides what is traumatic, not you.
But I will never really know. One of the most helpful pieces of advice I read in the early days was to not spend too long wondering or worrying about the cause. Focus my time and energy on making my dog feel safe and work with the dog in front of me.
Although I do need to recognise when he is feeling scared and make sure I don't keep making the same mistakes.
Whilst I may never know the cause, I wish I had recognised the signs earlier. I have since learned a huge amount on how I could have avoided prolonging his stress.
I am now much more understanding when I see other dogs struggling in the world and I hope what I have learned is helpful for others.