Background Suicide is a global public health concern causing the death of 703 000 people each year. Adolescents are an especially vulnerable population. Suicidality usually starts with suicidal...Show moreBackground Suicide is a global public health concern causing the death of 703 000 people each year. Adolescents are an especially vulnerable population. Suicidality usually starts with suicidal ideation (SI); therefore, this may be a useful preliminary measure of suicidal intent, and a point for suicide prevention. Our understanding of suicide and strategies for its prevention have not improved much in the past 50 years, which may be due to a missing piece in our current theories of suicidality: they do not address the self and the role it plays in suicidality. However, there is a theory that systematically addresses the self, namely the ego in psychoanalytic theory. Of particular interest are ego mechanisms of defense. Objectives This study aimed to investigate the relationship between ego mechanisms of defense and SI in adolescents to improve existing theories of suicidal behaviour by exploring whether specific ego mechanisms of defense can be identified as a risk factor for SI in adolescents aged 17-26. Methods This cross-sectional study was conducted using self-report questionnaires. The sample consisted of 98 university students. Logistic regression analyses were used to test the hypotheses. Results Immature and neurotic defensive categories were positive predictors of group membership of suicidal ideators, however only neurotic defense mechanisms were significant at p < 0.05. Displacement was also a positive predictor at p < 0.05. Finally, overall defensive functioning (ODF) had a significant negative correlation with SI at p < 0.05, however the logistic regression model was not significant. Conclusion Neurotic defensive category may be a useful predictor of SI. The defense mechanism displacement may also be a useful predictor of SI. ODF is negatively correlated with SI, suggesting a possibly useful relationship between the variables. These results are promising and seem worth further investigation, as defense mechanisms could be used as primary points of prediction and prevention of SI, and hence, suicidality.Show less