Dear Welcome to HCM We understand your concerns I went through your details. I suggest you not to worry much. Masturbation is natural and normal and even animals masturbate. Masturbation cannot reduce your concentration level. But the anxiety associated with masturbation can reduce your concentration. You are worrying that your masturbation habit may affect your concentration. Stop worrying, but reduce masturbation to twice or thrice week. Watch your health and concentrate on your studies and the problem ends. If you require more of my help in this aspect, Please post a direct question to me in this website. Make sure that you include every minute details possible. I shall prescribe the needed psychotherapy techniques which should help you cure your condition further. Hope this answers your query. Available for further clarifications. Good luck.