HUMAN METHADONE SELF-ADMINISTRATION AND THE GENERALIZED MATCHING LAW

The not absent study examined whether in humans the generalized matching law described the relation between relative responding and relative medicine intake by humans under harmonizing variable interval variable interval (cone VI VI) schedules of medicine reinforcement. Methadone-maintained patients, stabilized upon 80 mg per day of methadone, were recruited and trained to button pres for repeated deliveries of small turns (10 ml) of 0.08 mg/ml methadone solution. In the training phase, deliveries of methadone or vehicle solution were arranged beneath cone VI VI schedules of reinforcement. The mean interval for the methadone and for the vehicle options was 60 90 120 180 and 240 s During another phase, responding upon either of 2 buttons produc methadone solution. For the comparison option, the mean interval was 60 90 120 180 or 240 s For the concurrently available standard option, the mean interval was a constant 120 s When methadone and vehicle were available, methadone was preferr to vehicle. When methadone was available at either option, the generalized matching law described the relation between relative replication allocation and methadone intake. The arises extend the generality of the matching law to human remedy self-administration. The study also demonstrated the importance of reinforcement connection as a determinant of human behavioral allocation.

Drug of abuse function as reinforcers in humans (Griffiths, Bigelow, & Henningfield, 1980; Lamb et al., 1991; MeIIo & Mendelson 1980; MeIIo, Mendelson & Kuehnle 1982; MeIIo, Mendelson Kuehnle & venders 1981; Spiga & Roache, 1997) However, to our knowledge, remedy reinforcers and concurrent variable interval variable interval (cone Vl Vl) schedules have been used rarely to investigate quantitatively human remedy self-administration. The purpose of this inquiry was to determine whether in humans the generalized matching law (Davison & McCarthy, 1988; Williams, 1988) describes the relation between replication allocation and drug intake in humans.

Among nonhuman species, the estimates of the oblique direction are robust across reinforcers and settings (Baum, 1979; Davison & McCarthy, 1988; de Villiers, 1977) on the other hand are less so across human studies (Baum, 1975; Bradshaw & Szabadi, 1988; Kollins, Newland, & Critchfield, 1997; Pierce & Epling, 1983; Schroeder & Holland, 1969; Wearden, 1988; Wurster & Griffiths, 1979) Estimates may differ across species and studies because the discriminative stimuli associated with each alternative differ, the replication topographies differ, and/or the reinforcers differ (Kollins et al., 1997) For instance, human studies using social attention, significant visual stimuli, or fare rather than money as reinforcers obtain oblique directions closer to 1 (Buskist & Miller, 1981; Cliffe & Parry, 1980; Kollins et al., 1997) Kollins and colleagues (1997) directioned a review of data plants from 26 studies with humans responding upon concurrent schedules of reinforcement and set median slopes of 0.70 across a wide variety of reinforcers. In contrast, median direction downwards of 0.85 have been observ in studies with nonhumans.

Concurrent VI VI schedules and remedy reinforcers have been used to examine physic preferences and intake in animals. In monkey given access to cocaine below cone Vl Vl schedules of intravenous physic delivery, the relative rate of responding equaled the relative amounts of remedy intake (lglauer & Woods, 1974; Llewellyn, lglauer, & timber-lands 1976). Woolverton and his collaborators (Anderson & Woolverton, 2000; Woolverton, 1996; Woolverton & Ailing, 1999) also rest no differences in the parameters of the generalized matching law across pharmacological class and reinforcer (drug or food) Nonindependent coincident variable ratio variable ratio (cone VR VR) schedules of oral pentobarbital delivery, in which replys on either spout counted toward the completion of the couple VR values, produced relative rates of responding and relative remedy intake that were well described by dint of the generalized matching law (Meisch & Spiga, 1998)

We have unraveled a human oral methadone self-administration practice that closely approximates procedures used with nonhumans (Spiga, Grabowski, Silverman, & Meisch, 1996; Spiga, Huang, Meisch, & Grabowski, 2001; Spiga, Macenski, Meisch, & Roache, 1997) It permits choice, placebo mastery and multiple reinforcer deliveries within a session. These uncompounded bodys are necessary for determining the reinforcing events of drugs and for establishing behavioral baselines sensitive to pharmacological and behavioral manipulations (Henningfield, Cohen, & Heishman, 1991; Henningfield, Lukas, & Bigelow, 1986; Spiga et al., 1997; Spiga & Roache, 1997; Young & Herling, 1986) In this close attention these procedures were used to examine whether the generalized matching law described the relation between human answer allocation and drug intake beneath cone Vl Vl schedules of methadone delivery.

Method

Participants

Three male (RS-1016 RS-1055 and RS-1014) and sum of two units female (RS-1116 and RS-1019) methadone-maintained patients were recruited end the Treatment Research Clinic, University of Texas-Houston Health Science Center (Elk Grabowski, Rhoades, & McLellan, 1993) Participants' mean age was 384 (SD = 50) mean number of years of opioid use was 154 (SD = 62) and mean number of days of application of mind participation was 28.8 (SD = 43) RS-1014 and RS-1019 previously had participated in a application of mind of the effects of diazepam upon methadone selfadministration (Spiga et al., 2001)