A meth addict is easy to detect. There are some similarities between a bipolar and a meth addict but there are a lot of differences. For instance, a meth addict cannot keep consentration on one subject. They're eyes are big and they usually cannot control their mouth movement. Their hands will also be in constant motion. When they are high they will also make rapid and uncommon movements. A bipolar person is usually troubled by mood swings and irratic behavior. But not to the extent of a meth user.
The personalities may be similiar but looks aren't. Eventually a meth addict will become skinny, Their face will look sunk in and they will generally have sores on thier face (a little pimple they picked at over and over again) With meth addicts also watch for pupal dialation and frequent jaw movements. if you need more info email me.