title: Measuring motivation for medical treatment: confirming the factor structure of the Achievement Motivation Index for Medical Treatment (AMI-MeT).
abstract: BACKGROUND
  Developments in chemotherapy have led to changes in cancer care in Japan, with the government promoting a transition to outpatient chemotherapy. This requires patients and their families to participate more actively in treatment than in the past. However, it remains unclear how patients' motivation for medical treatment affects clinical consultations with their physicians. To investigate this, we developed a psychological index called the Achievement Motive Index for Medical Treatment (AMI-MeT), which comprises self-derived achievement motivation (AMS) and achievement motivation derived from others (AMO). However, its factor structure has not yet been confirmed in populations other than healthy university students. Thus, the aims of this study were to confirm the factor structure of the AMI-MeT in other groups and to determine the convergent and divergent validity of the AMI-MeT.
  
  
  METHODS
  The AMI-MeT was administered to university students (n = 414), apparently healthy workers (n = 154), and cancer patients (n = 51). Multi-group confirmatory factor analysis was conducted and the mean scores of the AMI-MeT were compared between the groups. Correlations between the AMI-MeT and the Self-Construal Scale, comprising independent self-construal (IndSC) and interdependent self-construal (InterSC) subscales, were investigated in another group of students (n = 335).
  
  
  RESULTS
  The multi-group confirmatory factor analysis supported a two-factor structure of the AMI-MeT: the weak invariance model was the best fit for the data. The mean scores of the AMI-MeT in apparently healthy workers and cancer patients were significantly higher than that in students (P < .01). The correlation analysis revealed that AMS scores were associated with IndSC scores (r = .25, P < .01) and AMO scores with InterSC scores (r = .30, P < .01).
  
  
  CONCLUSIONS
  The two-factor model of the AMI-MeT was deemed appropriate for all three groups, and the subscales of the AMI-MeT successfully reflected the self and other dimensions. The AMI-MeT appears to be an effective tool for measuring medical treatment motivation, making it useful in participant observational research on medical consultations for Japanese cancer treatment.
authors.affiliation: Uehiro Research Division for iPS Cell Ethics, Center for iPS Cell Research and Application (CiRA), Kyoto University, 53 Shogoin-Kawahara-cho, Sakyo-ku, 606-8507, Kyoto, Japan. hatta1@cira.kyoto-u.ac.jp.
authors.forename: Taichi
authors.initials: T
authors.lastname: Hatta
authors.forename: Keiichi
authors.initials: K
authors.lastname: Narita
authors.affiliation: Clinical Innovative Medicine, Institute for Advancement of Clinical and Translational Science (iACT), Kyoto University Hospital, 54 Shogoin-Kawahara-cho, Sakyo-ku, 606-8507, Kyoto, Japan. naritak@kuhp.kyoto-u.ac.jp.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Naria
authors.affiliation: Department of Medical Oncology, Kansai Electric Power Hospital, 2-1-7 Fukushima, Fukushima-ku, 553-0003, Osaka, Japan. yanagihara.kazuhiro@e5.kepco.co.jp.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yanagihara
authors.affiliation: Department of Target Therapy Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, 606-8507, Kyoto, Japan. hkkishi@kuhp.kyoto-u.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ishiguro
authors.affiliation: Department of Clinical Development, Kanazawa University Hospital, 13-1 Takara-machi, 920-8641, Kanazawa, Japan. toshi@staff.kanazawa-u.ac.jp.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Murayama
authors.affiliation: Clinical Innovative Medicine, Institute for Advancement of Clinical and Translational Science (iACT), Kyoto University Hospital, 54 Shogoin-Kawahara-cho, Sakyo-ku, 606-8507, Kyoto, Japan. yokode@kuhp.kyoto-u.ac.jp.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yokode
mesh_terms: D005163:Factor Analysis, Statistical; D005260:Female; D006282:Health Personnel; D006801:Humans; D007564:Japan; D008297:Male; D015233:Models, Statistical; D009369:Neoplasms / Q000188:drug therapy* / Q000523:psychology; D010045:Outpatients / Q000523:psychology*; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D010358:Patient Participation / Q000523:psychology*; D013334:Students; D055815:Young Adult