Rosalind Williams, formerly of St Mary's Lewisham Church of England primary school, south London, was found guilty of making the false certificate by England's General Teaching Council.
She was not present or represented at the disciplinary hearing in Birmingham last week.
In a written submission, Mrs Williams, who now lives in Spain, said she had been in a confused mental state and had not intended to mislead the school.
Medical evidence was considered by the panel in private.
Mrs Williams worked at the school from January 2000 until March 2003, when she resigned.
Mrs Williams wrote: "The events leading up to my resignation are very vivid and I often find myself thinking of them. I have not kept in touch with any staff member but have been thankful for their encouragement and prayers.
"I have always been and remain a dedicated teacher. Teaching is my vocation and in all normal aspects of life I'm an honest and trustworthy person."
The GTC banned her from teaching for a year after hearing that the school became suspicious about her qualifications when she asked for a day off to collect a second PhD.
Canon David Garlick, chair of governors, telephoned University College London where Mrs Williams claimed to have been awarded her first PhD and was told it had no record of her achieving a doctorate. There was no record either of her receiving a second PhD.
Mr Garlick also discovered that Mrs Williams had been awarded a pass on her natural sciences degree rather than the 2.1 she had claimed, and gave her a number of days to produce certificates.
Shortly before the deadline, the school's deputy head saw a PhD certificate on Mrs Williams's desk in a state of partial alteration which she photocopied and gave to Mr Garlick.
He suspended Mrs Williams after consulting lawyers. When he confronted her about faking the certificate she replied: "Oh, I'm a fool." He believed this was an admission of guilt.
Mrs Williams gave him an envelope containing her forged doctorate and another containing her resignation.
Mr Garlick said she had made a conscious and deliberate decision to mislead the governors into giving her a job, and her lies had undermined staff confidence.
The panel said her university degrees and professional qualifications must be authenticated before applying for future teaching posts.
She must also provide a report from a doctor showing she is physically and mentally fit to teach children at the end of the year's ban.