Twins (both men and women) had a substantially lower suicide rate compared with the general population. This supports the view that strong family ties reduce the risk for suicidal behaviour, say the authors.
The strongest risk factor for suicide is mental illness, and other studies have found mental illness to be slightly more common among twins than among singletons. "This should lead to a higher proportion of twins committing suicide compared with the general population, but our findings show exactly the opposite, further underscoring the importance of strong family ties," they conclude.