Do psychological traumas change a person's interests?

We need details. The question is too vague.

I can imagine scenarios where a person’s interest is changed and where it’s not.

They may. Depends on the person’s previous interests, and the specific traumatic incidents that occurred.

For example, if I am a philatelist and my brother died in a car wreck, I can’t see why the trauma would affect my interests.

On the other hand, if I am a downhill skier and my brother died in an avalanche, it could very possible change my psyche.

Trauma can prevent you from enjoying or participating in life as normal. You may no longer derive pleasure from an interest or may have anxiety about doing something. It seems perfectly reasonable to me.

Must trauma change your interests? No, I don’t believe so.

It very much depends on context but often yes.

Of course trauma changes a person. In many ways. This is why it’s so important to deal with it, preferably with an expert. PTSD is REAL. I know this first hand. Without dealing with the trauma that has effected you essentially you’re living a life full of missing out on the things you (used) to love.