@article{ZieglerEhrlenspielBrand2009,
  author    = {Ziegler, Matthias and Ehrlenspiel, Felix and Brand, Ralf},
  title     = {Latent state-trait theory : an application in sport psychology},
  issn      = {1469-0292},
  doi       = {10.1016/j.psychsport.2008.12.004},
  year      = {2009},
  abstract  = {Objective: Questionnaires are often applied in sports psychology to measure a person's trait or state. However, the extent to which the questionnaire captures differences because of trait or state influences is often unclear. The latent state-trait (LST) theory offers the opportunity to separate both variance sources. This separation allows estimating specific reliability coefficients. Design: The present paper gives a theoretical introduction to LST and its basic ideas. Using a real data set with N = 156 athletes we exemplify the steps necessary to derive the LST coefficients. All athletes filled out a comprehensive inventory assessing competitive anxiety on two occasions. Method: The data are analysed with structural equation models based on LST principles. Results: The results confirm the questionnaire's trait saturation. Conclusion: Finally, results are discussed in light of practical and theoretical implications.},
  language  = {en}
}
@article{HeissEngbertGroepeletal.2010,
  author    = {Heiss, Christian and Engbert, Kai and Groepel, Peter and Ziegler, Matthias and Brand, Ralf},
  title     = {Self-leadership and volition : distinct and potentially supplemental constructs?},
  issn      = {0033-2941},
  doi       = {10.2466/01.03.07.14.Pr0.107.5.447-462},
  year      = {2010},
  abstract  = {Self-leadership and volition are conceptually similar concepts. Both propose self-influence strategies that aim to improve the motivation and self-direction necessary to perform well. The present study assesses whether self- leadership strategies maintain construct-specific variance when compared with the similar strategies of volition. Results from a questionnaire study (N=320) indicate that self-leadership and volitional strategies are distinguishable and only moderately (r=.33) correlated. Self-leadership, therefore, supplements volition during goal attainment. Findings are discussed in light of the Rubicon model of action phases.},
  language  = {en}
}
@article{BrandHeckZiegler2014,
  author    = {Brand, Ralf and Heck, Philipp and Ziegler, Matthias},
  title     = {Illegal performance enhancing drugs and doping in sport: a picture-based},
  series = {Substance abuse treatment, prevention, and policy},
  volume    = {9},
  journal   = {Substance abuse treatment, prevention, and policy},
  publisher = {BioMed Central},
  address   = {London},
  issn      = {1747-597X},
  doi       = {10.1186/1747-597X-9-7},
  pages     = {11},
  year      = {2014},
  abstract  = {Method: Following a known-group differences validation strategy, the doping attitudes of 43 athletes from bodybuilding (representative for a highly doping prone sport) and handball (as a contrast group) were compared using the picture-based doping-BIAT. The Performance Enhancement Attitude Scale (PEAS) was employed as a corresponding direct measure in order to additionally validate the results. Results: As expected, in the group of bodybuilders, indirectly measured doping attitudes as tested with the picture-based doping-BIAT were significantly less negative (eta(2) = .11). The doping-BIAT and PEAS scores correlated significantly at r = .50 for bodybuilders, and not significantly at r = .36 for handball players. There was a low error rate (7\%) and a satisfactory internal consistency (r(dagger dagger) = .66) for the picture-based doping-BIAT. Conclusions: The picture-based doping-BIAT constitutes a psychometrically tested method, ready to be adopted by the international research community. The test can be administered via the internet. All test material is available "open source". The test might be implemented, for example, as a new effect-measure in the evaluation of prevention programs.},
  language  = {en}
}
@misc{BrandWolffZiegler2016,
  author    = {Brand, Ralf and Wolff, Wanja and Ziegler, Matthias},
  title     = {Drugs as instruments},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {434},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-406738},
  pages     = {11},
  year      = {2016},
  abstract  = {Neuroenhancement (NE) is the non-medical use of psychoactive substances to produce a subjective enhancement in psychological functioning and experience. So far empirical investigations of individuals' motivation for NE however have been hampered by the lack of theoretical foundation. This study aimed to apply drug instrumentalization theory to user motivation for NE. We argue that NE should be defined and analyzed from a behavioral perspective rather than in terms of the characteristics of substances used for NE. In the empirical study we explored user behavior by analyzing relationships between drug options (use over-the-counter products, prescription drugs, illicit drugs) and postulated drug instrumentalization goals (e.g., improved cognitive performance, counteracting fatigue, improved social interaction). Questionnaire data from 1438 university students were subjected to exploratory and confirmatory factor analysis to address the question of whether analysis of drug instrumentalization should be based on the assumption that users are aiming to achieve a certain goal and choose their drug accordingly or whether NE behavior is more strongly rooted in a decision to try or use a certain drug option. We used factor mixture modeling to explore whether users could be separated into qualitatively different groups defined by a shared "goal X drug option" configuration. Our results indicate, first, that individuals decisions about NE are eventually based on personal attitude to drug options (e.g., willingness to use an over-the-counter product but not to abuse prescription drugs) rather than motivated by desire to achieve a specific goal (e.g., fighting tiredness) for which different drug options might be tried. Second, data analyses suggested two qualitatively different classes of users. Both predominantly used over-the-counter products, but "neuroenhancers" might be characterized by a higher propensity to instrumentalize over-the-counter products for virtually all investigated goals whereas "fatigue-fighters" might be inclined to use over-the-counter products exclusively to fight fatigue. We believe that psychological investigations like these are essential, especially for designing programs to prevent risky behavior.},
  language  = {en}
}
@article{BrandWolffZiegler2016,
  author    = {Brand, Ralf and Wolff, Wanja and Ziegler, Matthias},
  title     = {Drugs As Instruments: Describing and Testing a Behavioral Approach to the Study of Neuroenhancement},
  series = {Frontiers in psychology},
  volume    = {7},
  journal   = {Frontiers in psychology},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1664-1078},
  doi       = {10.3389/fpsyg.2016.01226},
  pages     = {11},
  year      = {2016},
  language  = {en}
}
@misc{BrandHeckZiegler2014,
  author    = {Brand, Ralf and Heck, Philipp and Ziegler, Matthias},
  title     = {Illegal performance enhancing drugs and doping in sport},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-401404},
  pages     = {11},
  year      = {2014},
  abstract  = {Background: Doping attitude is a key variable in predicting athletes' intention to use forbidden performance enhancing drugs. Indirect reaction-time based attitude tests, such as the implicit association test, conceal the ultimate goal of measurement from the participant better than questionnaires. Indirect tests are especially useful when socially sensitive constructs such as attitudes towards doping need to be described. The present study serves the development and validation of a novel picture-based brief implicit association test (BIAT) for testing athletes' attitudes towards doping in sport. It shall provide the basis for a transnationally compatible research instrument able to harmonize anti-doping research efforts. Method: Following a known-group differences validation strategy, the doping attitudes of 43 athletes from bodybuilding (representative for a highly doping prone sport) and handball (as a contrast group) were compared using the picture-based doping-BIAT. The Performance Enhancement Attitude Scale (PEAS) was employed as a corresponding direct measure in order to additionally validate the results. Results: As expected, in the group of bodybuilders, indirectly measured doping attitudes as tested with the picture-based doping-BIAT were significantly less negative (eta(2) = .11). The doping-BIAT and PEAS scores correlated significantly at r = .50 for bodybuilders, and not significantly at r = .36 for handball players. There was a low error rate (7\%) and a satisfactory internal consistency (r(dagger dagger) = .66) for the picture-based doping-BIAT. Conclusions: The picture-based doping-BIAT constitutes a psychometrically tested method, ready to be adopted by the international research community. The test can be administered via the internet. All test material is available "open source". The test might be implemented, for example, as a new effect-measure in the evaluation of prevention programs.},
  language  = {en}
}
@misc{WolffBrandBaumgartenetal.2017,
  author    = {Wolff, Wanja and Brand, Ralf and Baumgarten, Franz and L{\"o}sel, Johanna and Ziegler, Matthias},
  title     = {Modeling students' instrumental (mis-)use of substances to enhance cognitive performance},
  issn      = {1866-8364},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-401441},
  pages     = {11},
  year      = {2017},
  abstract  = {Background: Healthy university students have been shown to use psychoactive substances, expecting them to be functional means for enhancing their cognitive capacity, sometimes over and above an essentially proficient level. This behavior called Neuroenhancement (NE) has not yet been integrated into a behavioral theory that is able to predict performance. Job Demands Resources (JD-R) Theory for example assumes that strain (e.g. burnout) will occur and influence performance when job demands are high and job resources are limited at the same time. The aim of this study is to investigate whether or not university students' self-reported NE can be integrated into JD-R Theory's comprehensive approach to psychological health and performance. Methods: 1,007 students (23.56 ± 3.83 years old, 637 female) participated in an online survey. Lifestyle drug, prescription drug, and illicit substance NE together with the complete set of JD-R variables (demands, burnout, resources, motivation, and performance) were measured. Path models were used in order to test our data's fit to hypothesized main effects and interactions. Results: JD-R Theory could successfully be applied to describe the situation of university students. NE was mainly associated with the JD-R Theory's health impairment process: Lifestyle drug NE (p < .05) as well as prescription drug NE (p < .001) is associated with higher burnout scores, and lifestyle drug NE aggravates the study demands-burnout interaction. In addition, prescription drug NE mitigates the protective influence of resources on burnout and on motivation. Conclusion: According to our results, the uninformed trying of NE (i.e., without medical supervision) might result in strain. Increased strain is related to decreased performance. From a public health perspective, intervention strategies should address these costs of non-supervised NE. With regard to future research we propose to model NE as a means to reach an end (i.e. performance enhancement) rather than a target behavior itself. This is necessary to provide a deeper understanding of the behavioral roots and consequences of the phenomenon.},
  language  = {en}
}
@article{EngelJacobsFydrichetal.2015,
  author    = {Engel, Mareike Carina and Jacobs, Ingo and Fydrich, Thomas and Ziegler, Matthias},
  title     = {Physical and psychological burden of psychotherapists in training},
  series = {Psychotherapeut},
  volume    = {60},
  journal   = {Psychotherapeut},
  number    = {6},
  publisher = {Springer},
  address   = {New York},
  issn      = {0935-6185},
  doi       = {10.1007/s00278-015-0055-2},
  pages     = {536 -- 545},
  year      = {2015},
  abstract  = {The demanding working and training conditions of psychotherapists in training (PiA) are discussed more and more frequently from social and research perspectives. The complementary focus on job and training pressure and its consequences have received little attention so far. The nationwide survey (N = 464) contains information on essential person-related and training-related risk factors and resources. Moreover, the study provides comparisons concerning different professional categories with high psychological and social demands as well as with the training conditions of psychotherapists in 2009. The study shows the difficulties and demanding situation of financing the training. The PiAs showed significantly higher stress levels than other groups of persons and comparably low resilience combined with a high working engagement. Only a few PiAs had a healthy behavioral and perceptional work pattern. The results underline the necessity for an examination of the training and working conditions of PiAs. Accordingly, options for interventions are presented.},
  language  = {de}
}