Objective
The objective of this study was to translate and adapt the National Institute of Mental Health Life Chart Method – Self/Prospective (NIMH-LCM-S/P™) instrument for self-monitoring of mood into Brazilian Portuguese and provide evidence of content validity. Additionally, a user guide was prepared for the instrument and evaluated by mental health professionals.

Methods
The study was divided into two stages – Stage 1: Translation and cross-cultural adaptation and Stage 2: Determination of content validity index (CVI) scores. The translation and cross-cultural adaptation process involved 37 participants between translators, experts, target population, and evaluators.

Results
The CVI was evaluated by 15 mental health professionals. 11 (78.57%) of the items evaluated attained the maximum CVI score of 1.00, which constitutes the highest level of content validity, and no changes were suggested by participants. Only one of the items evaluated had a CVI score lower than 0.80.

Conclusion
The final translated and adapted version of the NIMH-LCM-S/P™ and its user guide were evaluated by the target population and the mental health professionals. Both groups displayed satisfactory comprehension levels, suggesting there is potential for using this instrument in clinical practice to assess therapeutic interventions in Brazilian settings.