“My oldest child is mute in social settings and has been diagnosed with Selective Mutism. We are concerned our youngest will begin to mimic their older sibling’s behavior and develop SM, too. Should we be worried and what can we do to help?”

This is a great question. I will respond to your question with a question of my own: What is your youngest child like when their older sibling with SM is not around? 

In some cases, maybe they are shy. In others, the younger sibling may even be outgoing. In the case of the ladder, I wouldn’t worry too much about your youngest developing SM. 

Here’s what I would look to do: I would encourage your youngest to develop hobbies and interests of their own. This will create a level of independence for not only your youngest, but your oldest, too. For the younger child, this is where their true personality will shine through. Worries of them mimicking their older sibling will subside if their older sibling isn’t around in those social settings. This strategy also challenges your oldest child’s independence, as they will be less likely to depend on their younger sibling to do their communicating for them.  

With that being said, it certainly is possible for two siblings to develop SM. If this is the case, the earlier the treatment the better. The silver lining here is that once parents educate themselves on how to treat their child’ SM, they will be able to apply their learnings to both children at the same time. – Dr. E