Although mind-wandering (MW) is a part of attention deficit and hyperactivity disorder (ADHD), the impact of psychostimulants on excessive MW remains unclear. We aimed to elucidate how psychostimulants impact the MW of adult ADHD patients post treatment. This cross-sectional cohort study consisted of 54 randomly selected ADHD patients who applied to our psychiatry outpatient clinic and 40 healthy controls. The ADHD patients were administered methylphenidate or atomoxetine. A Semi-Structured Sociodemographic and Clinical Data Form, the Adult ADHD Self-Report Scale (ASRS), and the Mind Excessively Wandering Scale (MEWS) were applied. Routine psychiatric assessments in the 1st, 2nd, and 3rd months of pharmacological treatment were carried out by a psychiatrist. The pre-treatment MEWS score of the ADHD patients was 26.09 ± 1.92, which significantly decreased to 12.78 ± 2.54 post-treatment (F = 715.250,