For me abuse delayed my diagnosis. I was always symptomatic, even as an infant I did not sleep and screamed my way through life. When I finally got into therapy I was treated for MDD and PTSD. When I was diagnosed with bipolar I asked the therapist who had diagnosed the MDD and PTSD and he said the trauma presentation prevented him from seeing the bipolar even though looking back it was there. (It didn't help that I hid symptoms but the focus on PTSD was what really delayed diagnosis).