Table 2.

Delay discounting intervention studies

First author	Year	N1	Age ± SD	% male	DD type2	Delay3	Delayed amount	Intervention	Intervention cue type	Contrast conditions	WB threshold3
Boettiger	2009	9 AA, 10 HC	28.3 ± 5.8	58	Fixed	7–183	$2–$100	50 mg NTX	n/a	NTX versus placebo, now versus later	pcorr < 0.001
Peters	2010	30 H	25.4	50	IO	1–233	20.50€–80.00€	EFT	Text tag	[Episodic > control]	pFWE < 0.05, k = 10
Benoit	2011	12 H	27.3	33	Fixed	30–360	£28–£65	EFT	Text tag	[Imagine > estimate]	puncorr < 0.001, k = 10
Luo	2014	15 H	33.6 ± 7.7a	59a	IO	14–56	$20–$65	EP	Face images	[Fearful > happy]	Z > 2.3, pCC < 0.05
Sasse	2015	23 H	24.96 ± 2.79	52	IO	1–190	20.50€–79.50€	EFT	Text tag	[Episodic > control]	pFWE < 0.05
Hu	2017	22 H	24 ± 3	36	IO	7–365	> 20€	EFT	Text tag	[Episodic > control]	puncorr < 0.001, k = 350
Sasse	2017	22 HO	66.55 ± 4.02	41	IO	1–190	20.50€–79.50€	EFT	Text tag	[Episodic > control]	puncorr < 0.005, pCCFWE < 0.05
Wiehler	2017	23 PG, 23 HC	29.08a	100	IO	1–~200	> 20€	EFT	Text tag	[Episodic > control]	pFWE < 0.05
Wang	2018	17 H	22.7 ± 3.0	41	Fixed	8–1110	$10–$16,600	glucose	n/a	[Rinse > ingestion]	puncorr < 0.001, pCCFWE < 0.05

AA = abstinent alcoholics; HC = healthy control; H = healthy; HO = healthy older; PG = pathological gambler; IO = individually optimized, i.e., out-of-scanner DD parameterized trials for in-scanner DD; NTX = naltrexone; EFT = episodic future thinking; EP = emotional prime

¹Including only subjects with useable fMRI data; ²used in-scanner; ³”later” option delay in days; ⁴WB = whole brain (Subscripts indicate correction: corr = corrected, FWE = family-wise error corrected, uncorr = uncorrected, CC = cluster corrected)

^aProvided only for initial group before exclusions