BackgroundPrevalence of suicidal ideation increases rapidly in adolescence, and many choose not to seek help and disclose their ideation. Young people who do disclose suicidal ideation, prefer to do so with peers and family compared to mental health professionals, who are best placed to provide evidence-based treatment. This study aimed to identify key factors associated with young people’s decision to, or not to disclose suicidal thoughts to their mental health practitioner.MethodsA community-based sample of young Australians (16 - 25 years), who had experienced suicidal ideation and engaged with a mental health professional, completed an online questionnaire (N=513) which assessed demographic characteristics, severity of depression, anxiety, psychological distress, and suicidal ideation, lifetime suicide attempts, exposure to suicide loss, personal suicide stigma, prioritisation of mental health issues, and therapeutic alliance. Logistic regression analyses were used to identify factors associated with disclosure.ResultsThough the full sample had engaged in therapy, 39% had never disclosed suicidal ideation to their clinician. Those who had disclosed were more likely to report greater therapeutic alliance (OR=1.04, 95% CI=1.02–1.06), personal suicide stigma (OR=1.04, 95% CI=1.01–1.06), prioritisation of suicidal ideation (OR=.24, 95% CI=0.14-0.42), and lifetime history of suicide attempt (OR=.32, 95% CI=0.18-0.57). The most common reason for not disclosing was concern that it would not remain confidential.ConclusionThese findings provide new insights into why young people may not seek help by disclosing suicidal ideation, despite having access to a mental health professional, and establish evidence to inform practice decisions and the development of prevention strategies to support young people for suicide.