The use of the prospective NIMH Life Chart Method as a bipolar mood assessment method in research: A systematic review of different methods, outcome measures and interpretations

Abstract Background The severity of bipolar disorder can be assessed using the daily prospective National Institute of Mental Health׳s Life Chart Method (LCM-p). Also for scientific research the LCM-p, has been used frequently. However, processing and analyzing the LCM-p for research purposes, are challenging because of the multitude of complex measures that can be derived from the data. In the current paper we review the different LCM-p course variables (mood episodes, average severity, proportion of time ill and mood switches) and their definitions. Strengths and limitations and the impact of the use of different LCM-p course measures and definitions on the research results are described. Method A systematic review of original papers on the LCM was conducted using 9 electronic databases for literature between January 1996 and December 2014. Papers using other prospective charting procedures were not evaluated in the current study. Results The initial literature search led to 1352 papers of which 21 were eventually selected. A relatively wide variety of definitions of LCM-p course variables was used across the studies. Especially for the calculation of number of episodes and mood switch no univocal definition seems to exist. Across studies several different durations and severity criteria are applied to calculate these variables. We describe which variables and definitions are most suitable for detecting specific bipolar disease course characteristics and patterns. Conclusion In the absence of a golden standard for the calculation of LCM-p course variables, researchers should report the exact method they applied to their LCM-p data, and clearly motivate why this is their method of first choice considering their research aim.