I know some mental and mood disorders are caused by head trauma. To what extent of does the trauma have to be in order to be a likely cause?

All the medical history forms I've filled out always ask about head trauma that caused unconsiousness. So I always check no. However, I have fallen out of a tree(mostly landed on my back), I fell head first from six feet up onto a concrete floor, and I hit my head repeatedly at Airborne school practicing the landing for jumping from planes (which is entirely different from civilian skydiving)plus I hit my head twice on real jumps from the airplane. I never went unconcious and always knew my surrounding and such. I just keep wondering if I did any damage that would cause mental issues.