I would have to agree with the 6-12th house axis as a potential abuse indicator. I can only provide insight using my own chart, where I think the abuse is easily seen. I have a stellium in the 5th house in Virgo consisting of Uranus 6, Pluto 11, Sun 13 and Venus 15 all opposite Chiron 12 in Pisces in the 11th house. Chiron is generally very active in abuse charts, in my experience. To understand how the abuse materialized, I think you would have to look at my Moon in Aries in the 12th opposite my Mars in Libra in the 6th (both intercepted.) Obviously there is plenty to disseminate in these aspects, but upon first glance, it screams, soul crushing abuse from a cruel, domineering, controlling, very narcissistic mother.
There are, unfortunately, many aspects that could point to abuse. Harsh aspects from Mars to Saturn or Pluto would be some of the more difficult ones. I think you have to look at the placement of Chiron as well to see the effect of the abuse. If we do actually choose our lifetimes before we are incarnated, I always wonder why we would choose to suffer through parental abuse. For someone who hasn’t experienced it, I doubt they could understand. But for those of us who have gone through it, the reason behind it always seems elusive (to me at least.)