Suicide is one of top ten causes of death in most countries, and it has large impact both on families of victims and their environment. Suicide rate in Europe is 17.5 per 100,000 people and various activities from WHO and other organizations are underway with the goal of reducing suicide rates. Different underlying factors can contribute to suicide, and risk factors include both genetic and environmental factors, as well as probable existence of independent inheritance of a predisposition to suicidal behavior. In this paper we review actual epidemiological data on suicide behavior in Europe and Croatia, novel approaches and theories on suicidal behavior, and present our experiences in the diagnostic process. Some predictors of suicidality from our previous studies in PTSD patients are indicated. We reveal an integrative diagnostic model for PTSD and suicidality, based on integration of psychiatric, psychological, and biological markers. Preliminary algorithms for predicting suicidal behavior using data mining methods are shown, and some important variables are indicated. Further studies with larger numbers of patients and more parameters are needed for future development of this multidisciplinary approach to the assessment of suicidal behavior.