Devices, methods and systems are disclosed for assisting patients in behavioral modification and cessation programs aimed at terminating undesired behaviors such as smoking, alcohol use and others. Patient devices configured to be easily carried or worn including test units such as carbon monoxide blood level sensors with automated patient prompting for self-testing, analysis of test results and data logging are included in a networked system with a specifically designed treatment modality. Devices and methods disclosed are particularly suited to use in smoking cessation treatment and programs.