Limitations
The main limitation is the absence of longer term (e.g., 12-month) follow-up data. This study was an extension of a pilot feasibility study of self-help MCT that was approved under variation to contract and we did not have the time and resource to collect the longer term follow-up data. We cannot determine the effects of MCT alone in this study as it was designed to address a question of the “added effect” of self-help MCT when offered alongside CR. It is possible that combining MCT with psychological techniques included in some CR packages may impair rather than enhance MCT effects, because they rely on opposing mental processes [