Plain Language SummaryAlthough thinking of suicide for some period of time (suicide ideation) is traditionally viewed as necessary to attempt suicide in the future, many people who engage in suicide behaviour do not report specific suicidal thoughts during clinical interviews. We wanted to know how to predict suicide in these subjects; therefore, we investigated a number of promising characteristics in two different age groups of depressed patients (sample 1: n = 230; age: 18–65 years; sample 2: n = 258; age >60 years) who were negatively tested for the presence of suicide ideation. As expected, SB was not rare in these groups. Among younger patients, suicide attempts were a little more frequent than in the other group (15 vs. 9%); they more often involved men, those who had been victims of sexual abuse in childhood, those who had negative thoughts about themselves or were predisposed to bipolar disorder. On the other hand, in old age, suicide risk was correlated with neurological problems, foremost alterations in language and movement disorders, and cholesterol levels. Thanks to this information, to determine suicide risk is still possible even when intent to die is not reported.