I am a recently diagnosed 40-year-old male. I too have Ritalin and have been taking it for three months now. I started looking into my learning behaviour as I decided to change career and head to University, I found it really hard to maintain focus and knew something was wrong, I have inattentive ADHD, Ritalin helps keep me focused. I noticed when I first started taking Ritalin I got a great deal of euphoria which made me feel much better about life and I was able to sit for long periods of time and focus on tasks. That wore off after 8 weeks, I also found that after a miserable nights sleep Ritalin really doesn’t do much for me, the more rested I am, the less I need. My sleep quality improved and headaches stopped initially but have gone back to normal now. From the medical advice I was given, there is no problem with me stopping Ritalin, I was told I could take it as I needed it (up to 70mg per day). If you are a poor sleeper it might be worth looking into that, then trying Ritalin after a good nights sleep. I am listening to a webinar at the moment on this site about ADHD and sleeping better.