Over the past few years I have watched my wife's 22-year-old nephew descend into something bordering on insanity. At first he just seemed to have anger management issues (he got mauled by a pit bull as a teen, then his dad disowned him when his parents separated), but later he began this muttering to himself in nonsensical syllables. His condition worsened when he moved out of his mother's house and got his own apartment, and he went further downhill after his beloved grandmother died of cancer. Basically, he acts like one of those "crazy" homeless people you see in the streets: babbling to himself constantly, sometimes laughing and swearing, or waving his arms and making sound effects. He never stops. He sometimes claims that he can speak fluent German, which is a complete and total lie: he just babbles with a German accent. This came to a head a few months ago when his landlord tried to get him evicted, presumably because the neighbors were sick of hearing him talk to himself (he claimed it was because he turned up his stereo too loud 2 years prior!) He was able to talk the landlord out of it (probably because he pays his bills on time). But he threw a huge tantrum because he wanted to move in with us and we said no. He also threw a huge tantrum at a mall when his mother wanted to go to a different store. He was screaming at her in the mall at the top of his lungs. He won't admit there's anything wrong with him, so he refuses to see a counselor or a shrink. His mother offered to pay for one and he wouldn't do it. My worry is that he will eventually hurt himself or someone else (his tantrums and babbling are pretty scary and he gets very angry a lot). He is functional: he can drive, feed himself, bathe himself, show up to work on time (he works for UPS), pay his bills, but if you saw the way he constantly mutters to himself, you would assume he is insane. Does anyone want to make a diagnosis? Is there any way we can force him to get some help? It's a shame because he used to be a nice kid, and we've watched him slip away over the past few years.