Substance abuse is common issue in youth and may influence youth's suicide thoughts or actions. It can lead to social isolation, low self-esteem, loss of work or school, estrangement from family and friends – all these may create a core of stresses that may lead to suicidal tendencies.Analysis addictive factors correlating with occurrence of suicidal thoughts and behaviours among adolescents at the age of 18–20.Study was based on authorial, previously validated questionnaire, included 16 questions about suicidal thoughts. Questionnaires were filled by adolescents (age 18–20) of 21 Secondary Schools in Katowice.From the group of 965 adolescents, 28.8% had suicidal thoughts. From all respondents: 31.3% smoked, 92.7% drunk alcohol, 16.0% used legal hights and 30.9% – drugs; 35.8% of smoking adolescents had suicidal thoughts. In group of non-smoked adolescents – 25.6%. There was statistical significant difference (P = 0.0012) between these groups. Among adolescents who drunk alcohol, 28.8% had suicidal thoughts. In the group of non –drinking alcohol adolescents – 27.9%. There was no statistical significant differences (P = 0.88233) between these groups. There were 43.7% adolescents with suicidal thoughts who used legal hights. In the group of non-users of legal hights, 26.0% adolescents had suicidal thoughts.Adolescents that are using examined stimulants are in the group risk of suicidal thoughts and autodestructive behaviours. Results show the need of psychiatric and psychotherapeutic support that is aiming to prevent suicides and autodestructive behaviours in this group. Screening questionnaires that are assessing the problem of addiction within the adolescent may help to identity persons with suicidal tendencies.Disclosure of interestThe authors have not supplied their declaration of competing interest.