We tested the hypothesis of supporters of assisted dying that assisted suicide (AS) might be able to prevent cases of conventional suicide (CS).
By using data from the Federal Statistical Office, we analyzed the long-term development of 30,756 self-initiated deaths in Switzerland over a 20-year period (1999-2018; CS: n = 22,018, AS: n = 8738), focusing on people suffering from cancer who died from AS or CS.
While cancer was the most often listed principal disease for AS (n = 3580, 41.0% of AS cases), cancer was listed in only a small minority of CS cases (n = 832, 3.8% of CS cases). There was a significant increase in the absolute number of cancer-associated AS cases: comparing four 5-year periods, there was approximately a doubling of cases every 5 years (1999-2003: n = 228 vs.2004-2008: n = 474, +108% compared with the previous period; 2009-2013: n = 920, +94%; 2014-2018: n = 1958, +113%). The ratio of cancer-associated AS in relationship with all cancer-associated deaths increased over time to 2.3% in the last observation period (2014-2018). In parallel, the numbers of cancer-associated CS showed a downward trend only at the beginning of the observation period (1999-2003, n = 240 vs. 2004-2008, n = 199, -17%). Thereafter, the number of cases remained stable in the subsequent 5-year period (2009-2013, n = 187, -6%), and increased again toward the most recent period (2014-2018, n = 206, +10%).
The assumption that, with the increasingly accessible option of AS for patients with cancer, CS suicide will become "superfluous" cannot be confirmed. There are strong reasons indicating that situations and circumstances of cancer-associated CS are different from those for cancer-associated AS.