Attitudes toward nurse practitioners: influence of gender, age, ethnicity, education and income.

Survey research was undertaken to measure relationships between gender, age, ethnicity, education, income level, and an individual's attitude toward using a nurse practitioner (NP) for health care. Pender's Health Promotion Model provided the theoretical basis for the research initiative and instrument design. Following initial pilot work, 238 individuals were surveyed. While no significant differences on the basis of gender and race were found, high school graduates demonstrated significantly more positive attitudes toward NPs than non-high school graduates, and older subjects and those with lower incomes were less positively inclined to use NP services. These findings have implications for the marketing of NP services, NP education, and public education, and should be used as a basis for additional research in this area.

Lifting capacity. Indices of subject effort.

The association between manual materials handling and occupational low back injuries has generated a wide variety of devices and protocols for testing lifting capacity. The validity of these tests depends critically on the subject's effort during the evaluation. This study compares the accuracy of several physiologic effort indices in identifying maximal and submaximal lifting efforts. Twenty-one men and twenty-three women free from back pain underwent isometric, isokinetic, and isoinertial tests of lifting capacity applying 50 and 100% efforts in random order. Effort indices included isokinetic force/distance curve variation, isoinertial peak force: weight ratios and peak force--weight differences, and heart rates and peak force variances for all three modes. Differences between 50 and 100% effort means were significant at P less than 0.01 for isokinetic force/distance curve variation, isoinertial peak force: weight ratios, and peak force--weight differences, and for heart rates in all three modes using analysis of variance. Differences were not significant (P greater than 0.05) for peak force variances in any mode using Wilcoxon Signed Rank Tests. According to a discriminant analysis model with optimal cutoff values, the only effort indices with better than 60% accuracy in identifying maximal and submaximal efforts were isokinetic force/distance curve variation (74%) and isoinertial peak force: weight ratios (69%), peak force--weight differences (62%) and heart rates (65%). For each index, subjects were divided into three groups according to whether their lifting outputs during 50% effort bouts were greater than, equal to, or less than one half their outputs in the 100% effort bouts.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of dose on the ability of caffeine to serve as a reinforcer in humans.

This study tested the effects of dose on the reinforcing effects of caffeine in humans. Eight moderate coffee drinkers were given concurrent access to decaffeinated coffee vs. decaffeinated coffee to which different doses of caffeine (25, 50, 150 and 200mg/cup) were added. Subjects were tested across several independent double-blind trials. The coffees with 25mg of caffeine were repeatedly self-administered at a rate greater than that of decaffeinated coffee in two of six subjects, the 50mg dose in four of eight subjects, the 150mg dose in three of six subjects, and the 200mg dose in none of the three subjects tested. Headaches, drowsiness and fatigue occurred with use of decaffeinated coffee in five subjects. When these symptoms occurred, there was a greater probability of self-administration of the caffeinated coffee. We conclude that doses of caffeine similar to those in tea or soda can serve as reinforcers.

Triazolam as a discriminative stimulus in humans.

Seven healthy normal male and female volunteers (19-42 years) were trained to discriminate between the benzodiazepine triazolam (0.32 mg/70 kg; e.g. drug A) and placebo (e.g. drug B). During the first four daily sessions, drug A and drug B were administered orally in capsules 60 min prior to the session on alternate days and subjects were informed of the drug label at the time of drug administration. Subsequently, drug A and drug B were administered in a randomized-block fashion and subjects identified the drug code they thought they received. Subjects were informed of the drug code post-session. Once the criterion for discrimination was met (i.e. correct drug code identification on four consecutive sessions), the dose-effect curve for triazolam (0.1-0.75 mg/70 kg) was determined. The discrimination was acquired in all subjects; triazolam (0.32 mg/70 kg) and placebo produced approximately 85-95% correct responding. During the dose-effect curve determination, triazolam produced dose-related increases in triazolam-appropriate responding and self-reported sedation and drug strength. These results indicate that a triazolam-placebo discrimination can be acquired and that the triazolam discriminative stimulus effect is related to dose and to self-reported sedation.

Caffeine drug discrimination in humans: acquisition, specificity and correlation with self-reports.

This study evaluated the discriminative stimulus effects of caffeine in humans. Nine normal male and female volunteers (ages 18-28) were trained to discriminate between the methylxanthine central nervous system stimulant caffeine (320 mg/70 kg, p.o.) and placebo. Monetary reinforcers were earned for identifying correctly the letter code associated with each substance. After four training sessions, the ability to discriminate between the two training conditions was tested for 20 sessions (test-of-acquisition). In subjects who met the criterion for discrimination (i.e., greater than or equal to 85% correct responding on greater than or equal to 4 consecutive sessions during the last 10 test-of-acquisition sessions) dose-effect curves for caffeine (0, 56, 100, 180, 240 and 320 mg/70 kg) and for the benzodiazepine triazolam (0, 0.10, 0.32 and 0.56 mg/70 kg) were determined. Seven of the nine subjects learned the caffeine-placebo discrimination and their performance improved across the 20 test-of-acquisition sessions. The training dose of caffeine (320 mg/70 kg) produced stimulant-like self-reports that differed from placebo when the letter codes were identified correctly, but not when the letter codes were identified incorrectly. Novel caffeine doses produced dose-related increases in caffeine-appropriate responding (N = 4), whereas triazolam produced predominantly placebo-appropriate responding (N = 3) and self-reports that differed from both caffeine and placebo. Throughout dose-effect curve determinations, the training dose of caffeine and placebo continued to be identified correctly (range: 84-100% correct responding). These results suggest that a caffeine (320 mg/70 kg)-placebo discrimination 1) can be acquired and maintained, 2) is related to self-reported drug effects if the training conditions are correctly identified and 3) has some pharmacological specificity.

Smoking cessation among self-quitters.

We examined cessation among 630 smokers who quit abruptly on their own. Continuous, complete abstinence rates were 33% at 2 days, 24% at 7 days, 22% at 14 days, 19% at 1 month, 11% at 3 months, 8% at 6 months postcessation, and 3% at 6 months with biochemical verification. Slipping (smoking an average of less than 1 cigarette/day) was common (9% to 15% of subjects) and was a strong predictor of relapse; however, 23% of long-term abstainers slipped at some point. These results challenge beliefs that most smokers can initially stop smoking and that most relapse occurs later on postcessation.

Forced-choice versus free-choice procedures: caffeine self-administration in humans.

Methodological comparisons of procedures for drug self-administration are rare. In studies examining the reinforcing effect of caffeine in humans, caffeine self-administration usually has been inferred from performance under forced-choice procedures. In the present experiment, caffeine self-administration via coffee was compared under forced-choice and free-choice conditions; i.e., when subjects were and were not required to use a minimum number of coffees. Ten moderate coffee drinkers (2-7 cups/day) were assigned to forced- and free-choice conditions using a randomized cross-over design. Under each choice condition, subjects completed six independent, double-blind trials, consisting of a 2-day exposure period followed by a 2-day test period. During exposure, subjects consumed either decaffeinated or caffeinated (100 mg/serving) coffee on day 1 and the other coffee on day 2. During the test period, subjects had concurrent access to the same decaffeinated and caffeinated coffees. Under the forced-choice condition, subjects were required to drink at least four cups of coffee per day during the test period. Under the free-choice condition, subjects did not have a minimum-cup requirement. In general, the relative rate at which subjects self-administered caffeinated versus decaffeinated coffee was similar across choice conditions, even though subjects self-administered significantly fewer cups of both coffee types under the free-choice than the forced-choice condition. These results suggest that, at least for caffeine, forced-choice and free-choice procedures produce comparable results. Whether this finding generalizes to a context in which caffeine or another drug is more robustly self-administered, remains to be determined.

Long-term use of nicotine vs placebo gum.

Medical patients (n = 315) who wished to quit smoking were randomly assigned in a double-blind manner to receive either nicotine or placebo gum. Subjects were advised to stop gum use by 4 months. Among abstinent smokers, 46% of those receiving nicotine gum and 17% of those receiving placebo gum used the gum beyond the recommended 4-month period. By 10 months after cessation 17% of quitters receiving nicotine gum and 6% receiving placebo gum were still using gum. Gradual reduction of nicotine gum did not result in withdrawal and cessation of nicotine gum did not increase the probability of relapse to smoking or weight gain. We conclude that use of nicotine gum is due, in part, to the effects of nicotine; however, long-term use is uncommon.

Disability exaggeration as a predictor of functional restoration outcomes for patients with chronic low-back pain.

Many of the individual biological, psychological, and social factors attributed to low-back disability have been tested previously for their ability to predict treatment outcomes. To test the assumption that disability exaggeration affects treatment outcomes, models were developed to quantify this complex characteristic and to test its predictive value. Two hundred fifty-eight patients with chronic back disability entering a program of functional restoration were initially evaluated with a battery of tests, including measurements of trunk flexibility, lifting capacity, cycling endurance, self-assessments of pain and disability, and psychological attributes. On the basis of these measurements, patients were characterized as disability exaggerators if by peer comparison their self-assessments of pain and disability were in the most severe range despite high levels of physical capacity. Program completion and work status 1 and 2 years after treatment were compared between disability exaggerators and their peers. Individual initial attributes associated with program completion included pain intensity and Million Visual Analogue scores, lifting capacity, trunk flexibility, some Minnesota Multiphasic Personality Inventory and Million Behavioral Health Inventory scales, and cigarette smoking. One-year re-employment was associated with Minnesota Multiphasic Personality Inventory Scale 8, Wechsler Adult Intelligence Score-Revised, and cycling endurance. There were no significant associations between any individual factor and 2-year work status. Only two of the 12 disability exaggeration models distinguished between program graduates and dropouts, and none of the models accurately predicted return to work following treatment. Prescription of intensive multidisciplinary treatment should not be denied on the basis of any individual patient attribute or of disability exaggeration, as measured in this study.(ABSTRACT TRUNCATED AT 250 WORDS)

A behavioral approach to achieving initial cocaine abstinence.

OBJECTIVE: The aim of this study was to assess the efficacy of a behavioral treatment program for achieving initial cocaine abstinence in individuals enrolled in outpatient treatment for cocaine dependence. METHOD: Thirteen consecutively admitted outpatients were offered behavioral treatment consisting of contingency management procedures and the community reinforcement approach. Fifteen consecutively admitted outpatients were offered treatment with 12-step counseling. All 13 of the patients who were offered the behavioral treatment accepted it; 12 of the patients offered 12-step counseling accepted it. RESULTS: Eleven of the 13 patients in the behavioral treatment were retained for 12 weeks of treatment, compared with five of the 12 patients given 12-step counseling. Ten of the patients given behavioral therapy achieved 4 weeks of continuous cocaine abstinence, compared with only three of those given 12-step counseling. Six of the patients in the behavioral treatment group achieved 8 weeks, and three achieved 12 weeks; none of the patients in the 12-step counseling program achieved 8 weeks. CONCLUSIONS: The behavioral treatment described in this paper offers promise as an effective intervention for achieving initial cocaine abstinence. A randomized trial is underway to assess the generality of these findings.

Effects of caffeine on tobacco withdrawal.

Smoking cessation increases caffeine blood levels, and this has been hypothesized to cause some of the symptoms of tobacco withdrawal (e.g., anxiety and insomnia). To test this hypothesis, 10 coffee drinkers who smoked cigarettes were entered into a completely within-subjects experimental design in which the effects of caffeine dose (0, 50, and 100 mg/coffee serving) and smoking status (smoking versus abstinence) were examined over a 4-day period. Self-reported and observed measures of tobacco withdrawal, caffeine withdrawal, and intoxication, as well as psychomotor tasks and vital signs, were completed daily; blood was drawn at the end of each period. Temporary abstinence produced typical withdrawal symptoms but did not significantly increase caffeine blood levels. Caffeine did not increase the severity of symptoms but did decrease the severity of withdrawal-induced hunger. These findings suggest that, in the absence of increased blood levels, caffeine does not increase the severity of tobacco withdrawal.

Caffeine self-administration, withdrawal, and adverse effects among coffee drinkers.

Twenty-two coffee drinkers (three to seven cups per day) underwent repeated double-blind trials to test for caffeine self-administration, withdrawal, and adverse effects. Each trial consisted first of a randomized crossover period of 1 day of decaffeinated coffee and 1 day of caffeinated coffee (100 mg) to assess withdrawal and adverse effects of caffeine. Next, subjects were given 2 days of concurrent access to the two coffees. The relative use of the two coffees was used to assess caffeine self-administration. Reliable caffeine self-administration occurred in three of 10 subjects in study 1 and seven of 12 subjects in study 2. Withdrawal symptoms were headaches, drowsiness, and fatigue. The major adverse effect from self-administration was tremulousness. The occurrence of headaches on substitution of decaffeinated coffee prospectively predicted subsequent self-administration of caffeine. These results indicate that some coffee drinkers exhibit signs of a caffeine dependence, ie, they self-administer coffee for the effects of caffeine, have withdrawal symptoms on cessation, and experience adverse effects.

Effect of cost on the self-administration and efficacy of nicotine gum: a preliminary study.

METHODS. One hundred six smokers seen in a family practice received brief physician advice and a prescription for nicotine gum. Smokers were randomly assigned to pay $20, $6, or $0/box of nicotine gum and followed for 6 months. RESULTS. Decreased cost increased the incidence of obtaining gum, the amount of gum used, and the incidence of long-term use (P less than 0.05). Decreased cost also increased cessation attempts and 1-week cessation (P less than 0.05) and appeared to increase abstinence at 6-month follow-up (19% vs 6% vs 8%, P less than 0.10). Cost-benefit estimates suggest that an insurance plan, HMO, etc., would recoup any costs in subsidizing nicotine gum and perhaps incur a net financial gain.

Isokinetic trunk-strength deficits in people with and without low-back pain: a comparative study with consideration of effort.

The purposes of this study were to determine (a) the degree and distribution of isokinetic trunk strength deficits in people with chronic low-back pain (CLBP) and (b) to what degree subject effort during testing affects those deficits. We measured the isokinetic trunk strengths of three subject groups on the Cybex Trunk Extension/Flexion machine. Groups 1 and 2 consisted of 155 men and women with CLBP who were divided into maximal (n = 115) and submaximal (n = 40) groups according to their torque/position curve variability. Group 3 was made up of 32 back-healthy men and women who served as controls. The results demonstrated that men had higher flexion and extension torques than women did for all groups. The control group had higher flexion and extension torques than the maximal-effort CLBP group did. The extensors had a proportionally greater deficit than the flexors did in this LBP group. Comparing the two groups with CLBP, the maximal-effort group had higher flexion and extension torques than the submaximal effort group did, and the extensors showed a greater deficit. Degree of effort during testing does affect the results. Therapists should consider extensor strengthening and reeducation exercises when designing exercise programs to restore normal function in people with chronic CLBP.

Symptoms of tobacco withdrawal. A replication and extension.

Smokers (n = 315) who wished to quit were randomly assigned in a double-blind manner to groups using either nicotine or placebo gum. Self-reported and observed symptoms of tobacco withdrawal were collected before cessation and at follow-ups of 1 to 2 weeks, 1 month, and 6 months. Self-reported and/or observed anger, anxiety, craving, difficulty concentrating, hunger, impatience, and restlessness were the most prominent symptoms of tobacco withdrawal. These symptoms had returned to precessation levels by 1 month except increased weight, hunger, and craving continued for 6 months in many smokers. Nicotine gum decreased most symptoms, including craving and hunger but not weight. Abstinent smokers with more intense withdrawal were not more likely to relapse. Abstinent smokers who gained more weight were less likely to relapse.

Effect of dose on nicotine's reinforcing, withdrawal-suppression and self-reported effects.

Seventy-eight smokers trying to quit were randomly assigned to 0-, 0.5-, 2- and 4-mg doses of nicotine gum and tracked for 9 months. In the 1st week of abstinence, self-administration of gum did not differ by dose (4 mg = 2 mg = 0.5 mg = 0 mg). Higher doses did not more effectively suppress withdrawal than lower doses nor induce more accurate nicotine identification (4 mg = 2 mg = 0.5 mg greater than 0 mg). Higher doses slightly increased ratings of adverse effects in the 1st week (4 mg greater than 2 mg greater than 0.5 mg greater than 0 mg). Over the next 6 months, the two higher doses appeared to support more gum self-administration than the two lower doses (4 mg = 2 mg greater than 0.5 mg = 0 mg) in the subsample of long-term quitters (n = 20). Our results suggest the dose-response curves differ for nicotine gum's reinforcing, withdrawal-suppression and self-reported effects.

Effects of intranasal cocaine on human learning, performance and physiology.

The behavioral and physiological effects of intranasally administered cocaine (placebo, 48, 96 mg/70 kg) were examined in eight recreational cocaine users under controlled laboratory conditions. The 48 and 96 mg doses of cocaine significantly improved subjects' performance on the Digit Symbol Substitution Test above levels observed either prior to drug administration or when placebo was administered. These effects were discernible for up to 120 min after cocaine administration. Cocaine had no statistically significant effects on learning and performance of ten-response sequences. The 48 and 96 mg doses increased heart rate and blood pressure for up to 180 min, and increased subject ratings of drug effects and decreased skin temperature for 60-90 min after drug administration. Cocaine produced no significant effects on the electrocardiogram. To our knowledge, this is the first experimental demonstration that acutely administered cocaine can improve behavioral performance in rested subjects. In addition, the duration of cardiac effects in this study was longer than previously reported with intranasal cocaine, perhaps due to the concurrent behavioral testing.

Smoking history, instructions and the effects of nicotine: two pilot studies.

In Study 1, ten never-smokers, ten ex-smokers and nine current smokers received nicotine (2 mg) and placebo gum hourly for 4 hours on 2 consecutive days in a randomized, double-blind, cross-over protocol. Dysphoria from nicotine was greatest in never-smokers, intermediate in ex-smokers, and least in current smokers (p less than 0.05). On the third day, subjects were given concurrent access to the same gums and told to chew ad lib. Across all subjects, nicotine was an aversive stimulus (i.e., self-administered less than placebo). Nicotine was avoided most in never-smokers, intermediate in ex-smokers and least in current smokers (p less than 0.05). Study 2 used a similar protocol and compared the nine current smokers in Study 1 who were not told they would receive nicotine with eight informed smokers, i.e., smokers told they would receive nicotine. Although nicotine appeared to be a reinforcer more often in the informed smokers than in the uniformed smokers (63% vs. 22%), this result was not statistically significant. Our results suggest 1) past drug history can influence the stimulus effects of nicotine and 2) the effects of instructions on the response to nicotine may be less in experimental settings than in therapeutic settings.

Nicotine vs placebo gum in general medical practice.

Three hundred fifteen smokers who attended a family practice clinic and wished to quit smoking were assigned in a random, double-blind manner to receive either nicotine (2 mg) or placebo gum. Smokers initially received brief advice from a physician and nurse, a slide presentation and written materials (29 to 35 minutes), and a single follow-up visit (12 to 20 minutes) one week after cessation. After corrections for marital status and income, 10% of those who received nicotine gum and 7% of those who received placebo gum reported continuous abstinence for 11 months and passed observer and biochemical verification (this difference was not statistically significant). We conclude that, when used in a nonselected group of smokers along with a brief intervention in a general medical practice, the pharmacologic effects of nicotine gum to increase cessation are either small or nonexistent.

Functional restoration with behavioral support. A one-year prospective study of patients with chronic low-back pain.

Patients with chronic disabling low-back pain have poor prospects of returning to work. The authors tested a treatment program of functional restoration with behavioral support through 1 year prospective observation of patients disabled for an average of 19 months without evidence of surgically correctable disease. Ninety patients were studied: 59 program graduates, five program dropouts, 17 patients denied program authorization by their insurance carriers, and six crossover patients. Three patients were admitted but refused to participate in the treatment program. Initial demographic, physical, and self-assessment attributes were similar for all four groups. At year's end, 81% of program graduates, 40% of the dropouts, and 29% of those denied the program had returned to work. All six crossover patients were working 6 months after treatment. Program graduates showed significant improvements in self-assessed pain, disability, and depression, and in physical capacities after 3 weeks of treatment. These improvements were maintained through the year except for partial decreases in frequent lifting, cycling endurance, and isokinetic trunk extension strength. Functional restoration with behavioral support is an effective treatment for patients with chronic, disabling low-back pain, as measured by self-assessments, physical capacities, and return to work.