The lowest rates were reported by Auckland, Whanganui, and Hutt Valley District Health Boards.
The report points out that DHBs with older populations, smaller populations, and those with better access to the treatment will have the highest rates. Nationally, those in the 60-64 age group were most likely to be treated with ECT.
This year, the reporting period has been altered to calendar years, rather than fiscal years, meaning the report included an additional six-month period to avoid a gap. From July 2010 to December 2010, Southern treated more patients (34) with ECT than any other board.
Otago's mental health medical director, psychiatrist Dr James Knight, said it was inadvisable to compare district health boards, because of demographic and other factors.
The figures were useful for tracking year-on-year changes, however.
The Dunedin School of Medicine's department of psychological medicine was undertaking a clinical audit of ECT use at Southern DHB.
Its purpose was to learn more about the types of patients who received ECT in Southern, Dr Knight said, in an email.
Announced last October, when the board said it was responding to public concern about ECT use in Southern, it would be released early next year.
What is ECT? A pulse of electricity delivered to a patient's brain in order to produce a seizure. Although controversial, ECT is an effective treatment for various types of mental illness. Source: Director of mental health's annual report 2011.