Did Judy Garland have undiagnosed bipolar disorder?

There has been some speculation in books i have read about Judy Garland that she was an undiagnosed Manic Depressive.Her daughter Liza Minnelli thinks her Mum was Bipolar as she said a few years before her mum died that she would have extreme mood swings.Periods where she would stay in bed for days with severe depressions and other periods where she would be awake for days with severe agitation and irritability,full blown rages,delusions, paranoia and hallucinations.Perhaps her heavy drug use exacerbated her condition.Do you think this is true?Thanks