^{Nonhuman primates}

^{Deneau, Yanagita, and Seevers, 1969 (25)}

^{Rhesus monkeys}

^{Intravenous injections (1-5 mg/kg,an unspecified caffeine salt) were dependent on a lever-press response under FR 1 schedule; 24-hr access for as long as 18 weeks; if self-injection was not spontaneously initiated, then animals received programmed injections.}

^{Self-injection was maintained in all 5 monkeys at one or more dose(s), although programmed injections were required to initiate self-injection on some occasions; the pattern of self-injection was sporadic, with irregular intervals of self-injection alternating with periods of abstinence.}

^{Schuster, Woods, and Seevers, 1969 (96)}

^{Rhesus monkeys}

^{Intravenous injections (1-5 mg/kg caffeine) were dependent on lever- press response; 24-hr access; some animals tested after 1-month of programmed administration.}

^{Self-injection was maintained in 1 of 4 monkeys.}

^{Yanagita, 1970 (110)}

^{Rhesus monkeys}

^{Intravenous injections (0.25-4) mg/kg caffeine) were dependent on lever-press response; 4-hr access for 3 days after substitution for SPA.}

^{Self-injection was not maintained in 4 monkeys when caffeine was substituted for SPA, a CNS stimulant which maintains high rates of self-injection.}

^{Hoffmeister and Wuttke, 1973 (61)}

^{Rhesus monkeys}

^{Intravenous injections (0.2 mg/kg caffeine) were dependent on lever- press response under FR 10 schedule; 3-hr access for 6 days after substitution for codeine.}

^{Self-injection was not maintained at the single dose level tested in 3 monkeys when caffeine was substituted for codeine.}

^{Griffiths, Brady, and Bradford, 1979 (52)}

^Baboons

^{Intravenous injections (0.1-10.0 mg/kg caffeine citrate) were dependent on lever-press response under FR 160 schedule 3-hr time-out; 24-hr access for 15 days after substitution for cocaine.}

^{Self-injection was maintained in all 3 baboons at 3.2 mg/kg/inj; self- injection performance was sporadic across days in 2 or 3 baboons.}

^{Griffiths, Brady, and Bradford, 1979 (52)}

^Baboons

^{Intravenous injections (0.1-10.0 mg/kg caffeine citrate) were dependent on lever-press response under FR 160 schedule 3-hr time-out; 24-hr access for15 days after substitution for cocaine.}

^{Self-injection was maintained in all 3 baboons at 3.2 mg/kg/inj; self- injection performance was sporadic across days in 2 or 3 baboons.}

^{Griffiths, Sannerud, and Kaminski, (Figure 1), Previously unpublished data)}

^Baboons

^{Intravenous injections (0.1 mg/kg caffeine citrate) were dependent on lever-press response under FR 2 schedule; 50 injections or 2 hr, whichever came first, for 9-13 weeks.}

^{Self-injection was maintained in all 3 baboons; self-injection was sporadic across days in all 3 baboons.}

^Rats

^{Atkinson and Enslen, 1976 (3)}

^Rats

^{Intravenous injections (0.3-5 mg/kg caffeine) were dependent on Lever-press response under FR 1 schedule of 24-hr access for 3-7 days; some rats received forced pretreatment with caffeine for up to 98 hr before self-injection.}

^{Self-injection of caffeine was maintained in 5 of an estimated total of 18 rats tested at doses of 1-5 mg/kg; self-injection was maintained up to 4 days and decreased thereafter, self-injection occurred in animals with and without caffeine pretreatment.}

^{Collins, Weeks, Cooper, Good, and Russell, 1984 (20)}

^Rats

^{Intravenous injections (1 mg/kg caffeine) ere dependent on lever- press response under FR 1 Schedule; 24-hr access for 9 days, with the dose reduced to 0.1 mg/kg on day 6.}

^{Self-injection was maintained in 2 of 6 rats.}

^{Dworkin, Vrana, Broadbent, and Robinson, 1993 (28)}

^Rats

^{Intravenous injections (0.25 mg/injection caffeine) were dependent on lever-press response under FR 1 schedule; 1- to 3- hr access for 30 days after training food-maintained responding.}

^{Self-injection of caffeine was maintained in the 3 rats tested at about 15 and 8 responses/hr over first 5 and 30 days, respectively;maintenance of self-injection was concluded, although no vehicle control data were presented.}