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Suicide has been identified by the World Health Organization (WHO) as a global public health priority, given its persistently rising incidence despite expanding prevention efforts. It remains the 10th leading cause of death worldwide and the second leading cause among adolescents, imposing a considerable burden on individuals, families, and healthcare systems, with estimated medical and quality-of-life costs approaching USD 490 billion annually []. According to 2022 Centers for Disease Control and Prevention (CDC) data, approximately 50,000 suicide deaths occurred in the United States, with suicide ranking among the top four leading causes of death among individuals aged 10-34 years []. Suicidal ideation (SI) represents the earliest and most significant precursor to suicidal behavior, underscoring the need for early identification and targeted prevention. While psychiatric disorders such as depression and substance use have long been recognized as major risk factors, emerging evidence highlights sleep disturbances, particularly insomnia and nightmares, as independent and modifiable predictors of suicidality [-]. Insomnia, as defined in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), involves persistent difficulty initiating or maintaining sleep, resulting in impaired daytime functioning []. Among adolescents, insomnia is associated with diminished cognitive performance, emotional dysregulation, and lowered stress tolerance, factors that collectively exacerbate hopelessness and SI [,,]. A bidirectional relationship exists between insomnia and depression, wherein sleep disruption worsens affective instability, and mood dysregulation further disrupts sleep continuity []. Neurobiological evidence implicates prefrontal cortex hypoactivity and serotonergic and dopaminergic imbalances in mediating the link between poor sleep and impaired impulse control, thereby increasing vulnerability to self-harm and substance misuse [,]. Nightmares, defined as distressing dreams occurring during rapid eye movement (REM) sleep, have also been associated with an increased risk of suicidal ideation and behavior, potentially exerting an effect distinct from other sleep disturbances while interacting with coexisting psychiatric conditions []. Individuals reporting occasional nightmares had an approximately 1.57-fold higher risk of suicide, whereas those experiencing frequent nightmares had an approximately 2.07-fold higher risk compared with individuals without nightmares []. Furthermore, nightmares mediate the relationship between insomnia and suicidal ideation, suggesting a shared pathophysiological pathway involving emotional dysregulation and hyperarousal [].