To compare response, remission and switch (to other pulse width and/or electrode placement) rates and number of treatments between groups receiving right unilateral ultra-brief (RUL-UB), Bitemporal brief (BT), Bifrontal Brief (BF) and Right unilateral brief (RUL-B).

Data was collected from case notes in three centers. There were 133 in total, grouped as RUL-UB (50), BT (43), BF (23), RUL-B (17). Two of the three centers had a preferred electrode placement and pulse width.

Apart from age, the groups did not differ significantly on sex distribution, proportion of bipolar depression and psychotic symptoms. 56% of patients in RUL-UB switched compared to 12.5% in RUL-B, 4.9% in BT and none in BF (p value < 0.0001). When we considered patients who switched as treatment failures, remission rates were significantly different (p value < 0.0001) 40% in RUL-UB, 81.3% in RUL-B, 73.9% in BF and 78.0% in BT. Mean number of treatments in each group was significantly different (p value < 0.0001); 12.02 in RUL-UB, 10.2 in RUL-B, 7 in BF and 7.5 in BT. Post-hoc analysis indicated that RUL-UB differed significantly from BT and BF. Final response and remission rates including patients who switched were 98% and 82% in RUL-UB, 100% and 93.8% in RUL-B, 100% and 73.9% in BF and 97.7% and 83.7% in BT.

Majority commencing RUL-UB switched and received 4–5 more treatments compared to bilateral placements. RUL-UB ECT appears less effective and might not be appropriate as first line for all older adults as some patients at higher anaesthetic risk would benefit from having reduced number of treatments.