Table 1. The Details of the Sessions of Rumination-focused Cognitive-behavioral Therapy Protocol.

Session	Content
1&2	Initial assessment, Familiarizing patients with Chronic low back pain/ The relationship between depression, rumination and chronic pain/ The impact of depression and rumination on the onset and recurrence of symptoms, Rumination, and avoidance/ Treatment and treatment logic
3	Checking rumination episodes recording form, Initial case formulation using Functional analysis (FA), Using Antecedent-Behavior-Consequence form, Goal setting
4	FA of the rumination and avoidance (antecedents, usefulness, early warning signs and alternative responses of rumination)
5&6	Changing the style of thinking, representing different thinking styles, if-the plans, and consolidation of these plans
7	Finding functional alternatives for rumination, Replacing avoidance behaviors with approaching behaviors
8	Changing the processing style, Explaining the difference between concrete and abstract thinking style, determination the thinking style of the patients, identifying “Why” and “How” questions, Concreteness training, and imagery
9	Changing the processing style, Explanation the logic of the absorption, introducing absorbing activities
10	Introducing self-compassionateness and the examples of being compassionate to self and others
11&12	Preparing patients for the treatment termination, Relapse prevention and administrating the questionnaires