I was diagnosed with ADHD at a young age and it came with struggles. It doesn't that the world likes to medicate the problem rather than work on the problem. My brain has a hard time focusing on things that I feel uninterested in so you can imagine how hard it is for me to focus on my studies. Sometimes the Bible can feel like a 50-pond wait. Over the years I have found some tricks to help keep my focus like having music playing in the background or using a read-along app that helps keep my mind from wandering. These things help but it still feels like a struggle to get myself to sit down and focus on what is supposed to be the most important thing in my life. God knows I'm trying but that's why I want to do better when it comes to my prayer and study time. So to my brothers and sisters who struggle with these things, how do you overcome it?
When I was very young - in grade four, I think - my teacher called in my Dad for a conference about me. In the middle of a math quiz, or general classroom instruction, or even during a conversation with my teacher, I would...wander off in my imagination, or get utterly distracted by something outside that I had noticed through the classroom window, or fixate on a single comment the teacher had made to the neglect of everything else he was explaining. I had a terrible time staying focused on one thing for an extended period.
Strangely, the trade-off in my hyper-distractibility is that when I did focus on something, it was to the exclusion of all else, my attention narrow and very intense, my mind filled with a flurry of questions and extrapolations. As you can imagine, I was not a stellar student. In fact, my teacher was convinced there was something very wrong with me.
In the early nineteen-seventies there was nothing about ADHD in the common understanding of the public. I was just a "problem student" and my Dad's remedy for my mind darting off in all directions was the threat of a spanking if I didn't "pull up my socks" (which is an old way of saying, "Do better"). All through my public schooling I struggled as a student, like you, finding much of what I was supposed to learn very disinteresting and pointless. I say all this to explain that I get where you're coming from.
So, what advice can I give you as one ADHD person to another? Every person is unique and there is, then, no perfect "one size fits all" answer to your particular problem I can offer from my own experience. For me, what helped to focus my mind and keep it focused was having a very personal reason for doing so. I read, meditated and memorized Scripture that spoke directly to my personal experience, to what I was dealing with philosophically, spiritually and morally at the time of my Bible study. Rather than a merely academic accumulation of biblical data, I studied God's word for divine truth that I could apply immediately to my life and/or that answered a "burning question" I had about my faith.
God, too, has been very much "in the mix" of my Bible study, incentivizing my study of His word. At times, He has acted to make me desperate for His truth that could set me free from myself, or protect me from demonic attack, or answer the sharp challenges to my faith levelled at me by the secular World. Such desperation - for me, anyway - has had the effect of fixing me very intently and persistently on God's word.
As the years have passed and my history with God has enlarged, it isn't desperation that moves me into His word, but the prospect of knowing Him better and being well-equipped to serve Him. It's a joy to "connect the dots" of God's truth, and to be made wiser, and holier, and more delighted in Him, as a result.
Really, you ought to have been discipled by a believer who has a deep, rich, holy, truth-filled walk with God who can help you to enjoy the same. In discipleship, such a believer opens their life to you (as you open your life to them) so that you can see the truth they are teaching you worked out in the practical, mundane events of their life, the work of the Holy Spirit in them on display as they interact with you, their spouse, children, siblings, etc. The one discipling you works with you to engage practically with God's truth, guiding you into how to walk well with God. This process of discipleship is especially helpful to people who find concentrated, solitary study difficult because it directly connects learning spiritual truth to practical action and to relational interaction with a fellow Christ-follower, both things greatly enlivening study of God's truth.