Objective: Research indicates that the language used in addiction matters; therefore, the purpose of this study was to investigate whether differences in discursive and psychological processes exist in treatment manuals used for addiction treatment. Method: Using a synchronic corpus linguistic design, twelve-step facilitation, cognitive behavioral therapy, and motivation enhancement therapy manuals from Project MATCH were analyzed using LIWC2015. The log-likelihood ratio test was used to examine if difference in variables exist between the three manuals, with post hoc analysis to further examine differences. Bayesian information criterion was used to measure effect size, which ranged from weak to very strong. Results: Statistically significant differences exist in analytical thinking, authentic, emotional tone, first-person singular pronouns, second-person pronouns, third-person plural pronouns, negative emotion, male, and biological process words. Conclusions: Differences exist in psycholinguistic, linguistic, psychological, and physical processes between TSF, MET, and CBT. The greatest differences across all variables were between TSF and MET. Physical and mental aspects are addressed in TSF, whereas MET focuses on mental aspects. Knowledge of these and other differences support treatment matching for improved client outcomes. Findings of this study may have relevance to clinicians who provide addiction treatment, manual writers, addiction researchers, and clients with addiction issues. Further study of I words, which correlate with truth-telling, versus we words which support community, is suggested.