What Causes Difficulty In Paying Attention, Impaired Thoughts And Lack Of Interest?

I m having trouble I have always had trouble from when I was young with sleeping, concentrating, focusing, paying attention. sometimes I would get an assignment and understand it perfectly other times I would get the wrong impression and go off on a wild tangent. if the project was on something I like the wild tangent was more likely. I couldn t take thing that were serious for other people serious myself. while thing that were serious for me I would take very seriously. I couldn t always summon the energy to do some projects and I would lose interest quickly. I have been diagnosed with depression but later in life. I have been like this since I can remember. from a young child anyway.