When I was 13 I hit my head pretty hard sometime when it was light out and only remember having distorted vision walking up the driveway, don't remember walking home or going inside. I remember my dad pouring alcohol on my cuts and scrapes and waking up a few hours later in a bed confused, then I don't remember anything but I woke up in a tent in the woods early in the morning probably 3am with friends and my hand/wrist/fingers hurt like a ***** (they were broken and/or sprained). I don't remember too much head pain, but that could have been masked by the multiple torn ligaments and broken bones in a concentrated area.

I also hit my head kinda hard skiing and everything went dark for a second.

Maybe my mood swings, bad memory, and lack of being able to pay attention is because of that and not some probably genetic chemical imbalance? I never saw a doctor (except for a bone doctor that messed up my hand even more by splinting it wrong), but looking back this was right before my brain started being screwy.