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Biomedical subjects

Tom Hildebrandt

Publications and source records attributed to Tom Hildebrandt.

3 recordsLinked to original sources

Predicting intentions for long-term anabolic-androgenic steroid use among men: a covariance structure model.

Long-term use of anabolic-androgenic steroids (AASs) is associated with both positive and negative effects. The authors examined possible mechanisms by which these effects contribute to AAS satisfaction and predict intentions for future AAS use. Five hundred male AAS users completed an interactive Web-based instrument assessing the psychological and physical effects of AAS use. Covariance structure modeling was used to evaluate both direct and indirect effects of AAS consequences on satisfaction with AASs and intentions for future AAS use. Results suggest that gain in muscle mass and psychological benefits from AAS use uniquely contributed to both AAS satisfaction and intentions for future use. Side effects from AAS use also uniquely contributed to AAS satisfaction, but ancillary drug use was found to partially mediate this relationship, suggesting that the satisfaction of experienced AAS users is enhanced by their mastery of side effects through the use of ancillary drugs. The final model explained 29% of the variance in intentions for future AAS use. Mechanisms for sustained AAS use and implications for intervention and prevention strategies are discussed.

Adolescent↗

Rats' performance on variable-interval schedules with a linear feedback loop between response rate and reinforcement rate.

Three experiments investigated whether rats are sensitive to the molar properties of a variable-interval (VI) schedule with a positive relation between response rate and reinforcement rate (i.e., a VI+ schedule). In Experiment 1, rats responded faster on a variable ratio (VR) schedule than on a VI+ schedule with an equivalent feedback function. Reinforced interresponse times (IRTs) were shorter on the VR as compared to the VI+ schedule. In Experiments 2 and 3, there was no systematic difference in response rates maintained by a VI+ schedule and a VI schedule yoked in terms of reinforcement rate. This was found both when the yoking procedure was between-subject (Experiment 2) and within-subject (Experiment 3). Mean reinforced IRTs were similar on both the VI+ and yoked VI schedules, but these values were more variable on the VI+ schedule. These results provided no evidence that rats are sensitive to the feedback function relating response rate to reinforcement rate on a VI+ schedule.

Animals↗

Presence of muscle dysmorphia symptomology among male weightlifters.

Limited research exists on muscle dysmorphia (MD) in men and in nonclinical populations. The current study evaluated types of body image disturbance among 237 male weightlifters. Latent class analysis of 8 measures of body image disturbance revealed 5 independent types of respondents: Dysmorphic, Muscle Concerned, Fat Concerned, Normal Behavioral, and Normal. One-way analysis of variance of independent measures of body image disturbance and associated psychopathology confirmed significant differences between groups. The Dysmorphic group reported a pattern of body image disturbance consistent with MD by displaying a high overall level of body image disturbance, symptoms of associated psychopathology, steroid use, and appearance-controlling behavior. Findings generally supported classifying MD as a subtype of body dysmorphic disorder and an obsessive-compulsive spectrum disorder. Implications for studying body image disturbance in male weightlifters, and further evaluation of the MD diagnostic criteria are discussed.

Adolescent↗