<p>In psychiatry clinical trials, a validated instrument (or questionnaire) which consists of a number of questions (or items) is often used for evaluation of the safety and efficacy of a test treatment under investigation. This approach based on rating scales for evaluation of safety and efficacy of a test treatment under study, however, has been criticized of being subjective. To overcome the problem, the use of a composite index which combines the subjective rating scales and objective functional magnetic resonance imaging is proposed. For this purpose, statistical methods for development of composite index are derived. The proposed composite index is evaluated both theoretically and via extensive clinical simulation studies.</p>