Chris Davis

The new medication for attention-deficit hyperactivity disorder that Orioles first baseman Chris Davis has been approved to take this season is unlikely to be abused by players seeking an on-field edge, according to a medical expert.

After a second failed drug test for unauthorized Adderall use last season, Davis was suspended for 25 games, including the Orioles' final 17 regular-season games and seven postseason appearances. He also will have to sit out Opening Day but is allowed to participate in spring training games.

At last month's annual FanFest event, Davis said he was diagnosed with ADHD in 2008 and that he took Adderall to help him better function in everyday life. He had been granted a therapeutic-use exemption for Adderall by Major League Baseball in previous seasons but was denied in 2013, when he led the majors with 53 homers. He did not reapply for an exemption last season, when he admitted to taking Adderall multiple times to help his focus.

Davis has been granted another year-long exemption, but for the prescription drug Vyvanse. Unlike Adderall, Vyvanse is a slow-releasing stimulant that can last, according to research, up to 14 hours, according to Dr. David Goodman, assistant professor of psychiatry and behavioral sciences at the Johns Hopkins School of Medicine. (An extended-release formulation of Adderall called Adderall XR is also available.)

Both Adderall and Vyvanse are intended to treat ADHD symptoms, but the efficacy of each dose of Adderall lasts between three to five hours, so multiple daily doses often are required. Because Adderall is a fast-acting stimulant, it is more likely to be abused for recreational or performance-enhancing purposes, Goodman said.

"When Chris Davis is taking his Vyvanse, he's taking it to treat a medical condition," said Goodman, who has not treated Davis.

"One has to make a distinction between performance-enhancement drugs and medication used to treat medical illnesses. ADHD is a psychiatric condition for which medication serves to reduce symptoms and increase daily functioning. That's in contrast to not having any disorder and taking a stimulant medication because you want to have an edge."

Davis said Wednesday that getting an exemption for Vyvanse wasn't much different from receiving prior exemptions for Adderall from MLB. In both cases, he had to seek approval from the independent program administrator of baseball's Joint Drug Prevention and Treatment Program.

"I think the proof that I actually needed the medication was actually going through all the tests and all the protocol to make sure I was ADHD and to find a solution for that," Davis said. "I think, for me, that was the biggest weight off my shoulders, knowing that, 'OK, this is a condition I have. It hasn't changed with age.' And using the Vyvanse, it's a little more sophisticated [of] a drug. It's something I've really enjoyed, the differences between that and Adderall."

"With good reason, they want to make sure you're getting treated for the condition you have, and we exhausted every option to do that."

Because of its long-lasting effects, Vyvanse is becoming a popular medication to treat ADHD, Goodman said. It doesn't have the "crash" effect of Adderall and isn't likely to be abused because it releases into the body more slowly, he said.

"There are subtle differences," Goodman said. "As a group, the medication serves to improve attention and concentration and reduce distractibility and improve task completion, motivation and initiative. One is no better than the other, but people do report subtle differences in side effects and mood differences. So some people prefer one over the other."

Davis said he hopes that once people grasp the differences between the medications, they will understand he didn't attempt to use Adderall for performance-enhancing purposes.

"The fact that it's introduced into your system a different way, it allows you a longer window. I think it's proof that I wasn't using Adderall for on-the-field issues," Davis said. "It was something I was taking before I ever got to the field. And a lot of that had to do with all the distractions off the field. I've said it before. If you told me to focus in the batter's box for three or four seconds, I've done that my whole life. That wasn't the issue. And I think people understand that now that the details have kind of come."

Because of confidentiality provisions in baseball's Joint Drug Agreement between MLB and the Major League Baseball Players Association, the number of exemptions granted for stimulants such as Adderall and Vyvanse is not available, according to an MLB spokesman.

Eight of the 10 disciplinary cases last season involving stimulants were for unapproved Adderall use, according to the independent program administrator's annual report. None involved Vyvanse.

The Joint Drug Agreement allows MLB to disclose only the diagnosis for which exemptions are granted. MLB granted 112 exemptions for ADHD last season, seven fewer than it did in 2013, according to the independent program administrator's annual report.

"I think it kind of says something about where he was" with ADHD, Orioles manager Buck Showalter said. "When you have something [and] you've been diagnosed with it, they have a lot of things in place they have to follow to get approved. I think, as an industry, we were concerned that people were getting not legitimately approved. So we have a system in place that really looks at it closely. If Chris had followed the right procedure, he would have been approved for it."

Davis hasn't disclosed why he wasn't granted an exemption in 2013, and since the suspension was handed down Sept. 12, he has taken responsibility for the mistake.

"I think Chris had been very up front about, 'There were rules, and I didn't follow them the way they were supposed to be followed.' But the legitimacy of the diagnosis has always been the same," Showalter said. "It's not like he was taking steroids. He just didn't follow the proper procedure for something he was diagnosed with and was legitimate. That's unfortunate.

"I don't want guys like him to start apologizing for being extremely hard workers and strong. "I think sometime we make the mistake that every time a guy hits a ball a long way or throws the ball 98 miles an hour, [they're scrutinized.] But the players will tell you, that was created by the people who didn't do it the right way. Chris does it the right way."