Did Judy Garland have undiagnosed bipolar disorder?

I have read a few books on the life of Judy Garland and there has been some speculation that she was an undiagnosed manic depressive.Her daughter Liza Minnelli thinks her mum was bipolar. She said that a few years before her mum died she would have extreme mood swings.Periods where she would stay in bed for days with severe depression and periods where she would be awake for days on end with severe agitation and irritability, full blown rages, paranoia, delusions and hallucinations.Do you think this is true?Perhaps her heavy drug use exacerbated her condition.