Biomedical subjects
Publications and source records attributed to W Spring.
Symptomatology in multiple sclerosis (MS) depends on the areas of demyelination which can be situated anywhere in the white matter of central nervous system (CNS). Upper gastrointestinal tract symptoms are rarely reported. We recently saw a patient with MS who had disabling gastroparesis and dysphagia.
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Three studies examined self-administration of nicotine among exsmokers given concurrent access to nicotine (2 mg) and placebo gums during the first 2 weeks of abstinence from smoking. In Study 1 subjects were told they would receive either nicotine or placebo gum. With this instructional set, nicotine served as a reinforcer; i.e., subjects consistently self-administered nicotine but not placebo gum. However, subjects could discriminate gums on the basis of side-effects; thus, the ability of nicotine to serve as a reinforcer may have been due, not to its psychoactive effects, but rather because subjects believed the gum with more side-effects to be the active gum. In Study 2 we attempted to change this belief by telling subjects they would receive either the marketed nicotine gum or a new nicotine gum that is as effective as the marketed gum but has less side-effects (i.e., placebo). In Study 3 we attempted to change the belief by telling subjects that placebo gum had more side-effects than nicotine gum. With these two instructional sets, the stimulus properties of nicotine did not serve as reinforcer; i.e., subjects self-administered equal amounts of nicotine and placebo gums. To our knowledge, this is the first demonstration that instructions can control whether a drug will serve as a reinforcer.