Twenty percent of children and adolescent population are suffering from psychiatric disorders, according to World Health Organization. Above that, clinical work and previous published reports point to increase of self-harm behaviour incidence and prevalence in many countries, including Croatia.

To compare defence mechanisms in adolescent patients with deliberate self-harm behaviour and without it.

To explore differences in adaptive and maladaptive defence mechanisms in adolescent patients with self-harm behaviour and without this behaviour; to gain better insight in possible perception and functioning patterns in these two patient subgroups. To assess the effect of possible differences on early diagnostic procedure and therapeutic plan.

Defence Style Questionnaire (DSQ) was administered to 150 patients aged between 14 and 18 years on their first visit to child and adolescent psychiatrist. Sevety-nine patients had history of self-harm behaviour and 81 patients had negative anamnestic data on such behaviour.

Comparison of defence mechanisms in these two patient subgroups showed a statistically relevant difference in using defence mechanisms.

Results of this study showed significant difference between patients with self-harm behaviour and without such behaviour regarding used defence mechanisms. Awareness of specific mental patterns in patients with self-harm behaviour provides better assessment of suicidal risk and optimal individual approach planning.

The authors have not supplied their declaration of competing interest.