Table 2.

Pharmacological studies reporting effect on logical reasoning

Reference	Sample	Drug type	Drug	Route	Dose	Max dose1	Effect2	Effect dose3
Evans & Smith, 1964	4F/M versus 4F/M	Agonist	Morphine	PO	16 mg	low	↑	low
Zacny, Lichtor, Thapar, et al., 1994a	5F/7M	Agonist	Morphine	IV	10 mg	high	...	_
		Partial Agonist	Butorphanol	IV	0.5, 1, 2 mg	high	...	_
Zacny, Lichtor, Klafta, Alessi, & Apfelbaum, 1996a	3F/7M	Agonist	Codeine	PO	60 mg Codeine/600 mg Acetaminophen	low	...	_
		Mixed agonist	Butorphanol	TN	1, 2 mg	high	...	_
Zacny, Conley, & Galinkin, 1997a	5F/11M	Agonist	Morphine	IV	10 mg	high	...	_
		Mixed agonist	Buprenorphine	IV	0, 0.075, 0.15, 0.3	high	↓	high
Zacny, Conley, & Marks, 1997b	4F/12M	Agonist	Morphine	IV	10 mg	high	...	_
		Mixed agonist	Nalbuphine	IV	2.5, 5, 10 mg	high	...	_
Walker & Zacny, 1998	3F/9M	Agonist	Codeine	PO	60, 120 mg	med	...	_
		Agonist	Morphine	PO	20, 40 mg	med	...	_
Zacny, Hill, Black, & Sadeghi, 1998	15F/2M	Agonist	Hydromorphone	IV	0.33, 0.65, 1.3 mg	high	...	_
		Agonist	Morphine	IV	5, 10 mg	high	...	_
Walker & Zacny, 1999	6F/10M	Agonist	Hydromorphone	IV	Cumulative injections of: .33, .65, 1.3 mg	high	...	_
		Agonist	Meperidine	IV	Cumulative injections of: 17.5, 35, 70 mg	high	...	_
		Agonist	Morphine	IV	Cumulative injections of: 2.5, 5, 10 mg	high	...	_
Hill & Zacny, 2000	5F/12M	Agonist	Hydromorphine	IV	Cumulative injections of .33, .65, 1.3 mg	high	...	_
		Agonist	Morphine	IV	Cumulative injections of 5, 10 mg	high	...	_
Marsch et al., 2001	18M	Agonist	Morphine	IV	Three infusion rates (2 min bolus, 15 min, and 60 min) of 5, 10 mg	high	...	_
Walker, Zacny, Galva, & Lichtor, 2001	5F/10M	Agonist	Morphine	IV	2.5, 5, 10 mg	high	...	_
		Mixed agonist	Butorphanol	IV	0.5, 1, 2 mg	med	↓	med
		Mixed agonist	Nalbuphine	IV	Cumulative injections of 2.5, 5, 10 mg	high	...	_
		Mixed agonist	Pentazocine	IV	7.5, 15 mg	low	...	_
Zacny & Gutierrez, 2003	9F/9M	Agonist	Morphine	PO	40 mg	med	...	_
		Agonist	Oxycodone	PO	10, 20, 30 mg Oxycodone	high	...	_
Zacny, 2003	9F/9M	Agonist	Hydrocodone	PO	5 mg Hydrocodone/1.5 mg Homatropine, 10 mg Hydrocodone/3 mg Homatropine, 20 mg Hydrocodone/6 mg Homatropine	med	↓	med
		Agonist	Morphine	PO	40 mg	med	↓	med
Zacny & Gutierrez, 2008	8F/8M	Agonist	Hydrocodone	PO	5 mg Hydrocodone/325 mg Acetaminophen, 10 mg Hydrocodone/650 mg Acetaminophen	med	↓	med
		Agonist	Oxycodone	PO	5 mg Oxycodone/325 mg Acetaminophen, 10 mg Oxycodone/650 mg Acetaminophen	med	↓	med
Zacny & Lichtor, 2008	10F/10M	Agonist	Morphine	PO	30, 60 mg	high	↓	high
		Agonist	Oxycodone	PO	10, 20 mg	high	↓	high
Zacny & Gutierrez, 2009	10F/10M	Agonist	Hydrocodone	PO	15 mg Hydrocodone/487 mg Acetaminophen, 30mg Hydrocodone/975mg Acetaminophen	high	↓	med
		Agonist	Oxycodone	PO	10 mg Oxycodone/487 mg Acetaminophen, 20 mg Oxycodone/975 mg Acetaminophen	high	↓	med
Zacny & Gutierrez, 2011	6F/8M	Agonist	Oxycodone	PO	10 mg	med	...	_

F = female; M = male participants. Studies used within-subject designs unless otherwise noted.

¹Estimated dose for agonists based on morphine equivalent of the maximum dose of in the respective study. For antagonist drugs, the estimated dose is preceded by a minus. See caption of Figure 2 for more details.

²Arrow indicates significantly improved (↑) , impaired (↓), mixed effects (↕) or null-effects (…) on performance relative to a placebo control condition.

³Minimum estimated dose at which the indicated effect is significantly different from placebo.