Are we really supposed to believe that Mackenzie didn't know about Ryan's drug problem?

Probably the biggest shocker on last night's Teen Mom OG reunion special was the letter that Mackenzie read to Maci regarding Ryan's drug use.

During the show, Mackenzie sat down and read a letter she had written about the situation. As soon as Mackenzie started reading, we were all in disbelief, as Mackenzie started blaming Maci for everything. But the craziest part of the letter was that Mackenzie accused Maci of being the only person to know about the drug problem.

Maci had an excellent response...but being the classy person that she is, she never mentioned the elephant in the room... Is it really possible that Mackenzie didn't know that Ryan had a drug problem?

Ryan has been showing strong signs that something was wrong for a long time. His behavior has not looked normal for this entire season of Teen Mom OG -- not to mention past seasons. And Ryan's drug problem has been a staple of the tabloids for years.

Also, as we wrote in a previous post, a few years ago Ryan was in a head on collision because his car drifted onto the other side of the road. While he wasn't caught with drugs on scene, the crash does seem pretty suspicious, and you'd think his family would wonder how such an accident could occur.

Now, we can't know for sure what is in Mackenzie's mind -- it's totally possible that she was oblivious to Ryan's drug use and that everything in her letter was true. But it's important to remember that Mackenzie had a strong incentive to write that letter. The video of Mackenzie and Ryan may have exposed them to lots of legal trouble, affecting custody battles and other issues.

For instance, because of Ryan's drug problem, Mackenzie's ex (Zachary Stephens) is resuming his custody battle. Stephens says that he's going to use the video as evidence that Mackenzie and Ryan aren't fit for custody.

If Mackenzie did know about Ryan's problems, that would look especially bad for her in a custody hearing. If she was totally oblivious, then the court is likely to look more favorably upon her.

Of course, Mackenzie and Ryan's family also need to think about the custody issues with Maci, as well as other potential legal issues that may arise, such as potential charges due to the driving video.

Given the magnitude of her problems, I wouldn't be surprised if Mackenzie consulted with a lawyer before writing that letter... It was likely the best way for her to respond to the devastating video.

What do you think? Was Mackenzie completely oblivious? Or did she know something? Tweet us.

MTV