Britney Spears can't seem to last in rehab for more than several hours.

For the second time in less than a week, Spears has checked out of a facility within hours of checking in.

TMZ.com says Spears just couldn't handle rehab. "The Insider" reports that Spears called a car service to pick her up.

She made the same quickie visit to another facility last week.

Her people still haven't said exactly why she voluntarily admitted herself.

Spears grabbed headlines over the weekend after she shaved her head and visited a tattoo parlor in Los Angeles.

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