Hi Maxima & Welcome! I may not be an expert, but I would say your friend, if she's not abusing it, maybe her husband is. I have heard of parents taking their childs meds to see what they feel like. Thats how some realize they also have add/adhd. If thats the case, maybe her husband should see a doc. If they just make him feel good, he shouldn't be taking it.
I know how hard it is to say no to a friend, but you shouldn't give up yours. It sounds like you are using them as prescribed, and 40mg twice a day is ALOT! I now take adderall XR, 30mg twice a day. To me, thats alot! The "stolen from car meds" is a very familiar story to docs and is now posted in some offices. In my 30's, I was addicted to vicodin b/c of back pain, went through them like candy. To get more, I said mine were also stolen from my car. It was believable than. I thought I had a real original story! They gave me more. I also ended up in rehab later on. But it was for the best.( I didn't think that at the time )
So what I might do in your case is to have a talk with her. Explain to her that even though you get a 3 month supply, that has to last. also find out if she is building up a tolorence to the adderall, b/c taking more won't help. She may need to try something different. I really don't think she's is giving it away(hopefully she's not selling it). If her hubby is using it, she needs to have a talk with him. My hubby use to take my Fiorcet for headaches, now he gets his own.
GOOD LUCK and please don't give up yours. Since your close friends, she may open up to you sooner than you think. Just go easy at first.