Leeann Christian

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Exogenously administered opiates are recognized as rewarding and the involvement of dopamine systems in mediating their apparent pleasurable effects is contentious. The aversive response to naloxone administration observed in animal studies suggests the presence of an endogenous opioid tone regulating hedonic state. We sought evidence for the requirement(More)
Previous studies have shown that ratio size influenced the development of tolerance under simple and multiple schedules, but not under progressive-ratio (PR) schedules. PR schedules share certain features with mixed-ratio (MR) schedules, and pilot data suggested that ratio size fails to modulate tolerance to cocaine or morphine under MR schedules. The(More)
Individuals with developmental disabilities are often unable to influence their social environment in traditional ways (i.e., vocal language) and frequently exhibit challenging behaviors (e.g., aggression and self-injury) because such behaviors were previously reinforced under similar conditions. While the area of positive reinforcement manding has been(More)
This study examined the effects of progressive relaxation training on the disruptive behaviors of a boy with autism. Moreover, his overt relaxed behaviors before and after relaxation training were measured using the Behavioral Relaxation Scale (Poppen, 1988, Poppen, 1998). After the participant received training in progressive relaxation procedures a(More)
The gender of participants in articles published from 1991 through 2000 in eight journals relevant to mental retardation was determined. Overall, participants were used in 65% of the articles; gender was not reported in 26% of them. When gender was reported, 6%, 8%, and 60% of the investigators used females only, males only, and both sexes, respectively.(More)
Mainstream psychiatry has all but ignored the clinical needs of persons with developmental disabilities. With some notable exceptions, individuals in this group have been served in the community by behaviorally oriented psychologists or relegated to long-term institutional care. However, effective interventions are available, beginning with a functional(More)
The present survey determined whether articles describing attempts to alter behavior in people with mental retardation and Attention-Deficit/Hyperactivity Disorder (ADHD) (a) reported whether or not participants were receiving medications, (b) evaluated drugs as independent variables, and (c) evaluated (or discussed) interactions between pharmacological and(More)
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