Table 3.

Tests for additive interaction between substance use disorders and poverty on first time suicide attempt/thought* (N=31,568)

Variable	Effect When Not In Poverty	Effect When In Poverty	Test of Interaction
	RD% (SE) p-value	RD% (SE) p-value	IC% (SE) p-value
Substance Use Disorders
(ref = No Disorder)
Alcohol Use Disorder Only	0.7% (0.5%) 0.14	0.1% (0.1%) 0.95	−0.7% (1.1%) 0.55
Drug Use Disorder Only	2.5% (1.5%) 0.10	0.6% (2.5%) 0.80	−1.9% (2.9%) 0.52
Both Alcohol/Drug Use Disorders	0.5% (1.0%) 0.59	2.7% (2.5%) 0.29	2.1% (2.7%) 0.43

RD% = Risk Difference. For example the RD%=0.1% for substance use disorder in the Effect when in Poverty column means that the risk of first-time suicide attempt/thought is 0.1% higher when a person in poverty has an alcohol use disorder only compared to not having any substance use disorders but still being in poverty.

IC% = Interaction contrast Risk Difference (This is the difference in the RD effect when in poverty compared to when not in poverty).