A top U.S. psychologist claims Britney Spears will be dead in six months if she doesn't get help for her "chronic mood disorder."

Dr. Lillian Glass has done a Dr. Phil and gone public with her diagnosis in the hope that Brit will seek medical treatment.

The renowned Beverly Hills doctor tells America's Globe: "Unless Britney is locked away or put into a treatment program, she is going to die in six months - or even sooner.

"In my opinion, she suffers from cyclothymia, a chronic mood disorder in which short periods of mild depression are followed by short periods of hypomania.

"That explains why one minute she (Spears) can appear perfectly sane and the next she's exhibiting totally crazy behaviour."

Dr. Glass adds that Brit is "definitely a candidate for suicide if she isn't treated immediately."

Yesterday TMZ quoted sources who claim that the pop mess has multiple personalities, including "the British girl" and "the weepy girl, the diva, the incoherent girl."

The site further reports that when Brit loses her British accent, she has no idea what happened during the time she assumed the personality.