In her early twenties, Lucia Joyce pursued several brief and unsuccessful relationships. Among her romantic interests were Samuel Beckett, and her drawing instructor, Alexander Calder. Family and friends observed increasingly erratic behavior from Joyce during this period, and in February 1932, she was institutionalized for a short time after throwing a chair at her mother. She was engaged to Alex Ponisovsky in March 1932, but wedding plans were abandoned after the further decline of her mental health.
Lucia Joyce spent the next several years in and out of sanitariums. She was seen by numerous doctors and analysts, including Carl Jung, and was diagnosed at different times as neurotic, schizophrenic, and manic-depressive. In 1935, she was committed to an asylum near Paris and remained institutionalized for the rest of her life, dying December 12, 1982, in St. Andrew's Hospital in Northampton, England.