Untangling the temporal association between daily urges to die by suicide and to use substances

•People with higher substance use urges were more likely to report suicide urges on the same and next day.•An increase in daily substance use urges was associated with reporting suicide urges on the same day.•Both greater sadness and anger led to next-day suicide urges while accounting for substance use urges.•Sadness may explain the effects of anger on the influence of substance use urges on suicide urges. The current study examined the potential bi-directional associations between urges to die by suicide and to use alcohol or drugs as well as sadness and anger in relation to these urges. Forty individuals with suicidal thoughts, binge drinking behaviors, and emotion regulation difficulties, who were recruited for a clinical trial of internet-delivered Dialectical Behavior Therapy skills training, completed daily diaries on suicide and substance use urges and emotions over twenty-one days. Results indicated that higher daily peak substance use urges were associated with a greater likelihood of reporting suicide urges on the next day. Participants with higher and an increase in peak substance use urges (relative to their daily average) were both more likely to report suicide urges on the same day. Furthermore, both daily peak sadness and anger ratings predicted next-day suicide urges while accounting for substance use urges, though sadness may be a stronger predictor. These findings suggested a possible unidirectional pathway from urges to use substances to subsequent urges to die by suicide and a unique role of sadness.