A small modafinil pilot found reduced self-reported methamphetamine use without a significant reduction in amphetamine-positive urine results. The disagreement shows why a treatment claim must identify its endpoint rather than treating all measures of use as equivalent.
McGaugh and colleagues enrolled eight people in an open-label study; seven completed intake and began the study, and four completed the full course. Modafinil was increased to 400 mg daily. Participants also received cognitive behavioral therapy and contingency-management incentives.
The primary purpose was preliminary safety and tolerability. The study was not blinded and had no placebo group. Neither changes in symptoms nor changes in reported use can therefore be attributed exclusively to the medication.
Supervised urine samples were collected three times weekly and screened for amphetamines using a 300-ng/mL cutoff. Participants also reported methamphetamine use weekly. The analysis found a significant decline in self-reported use but no significant change in positive urine screens (p = 0.61). All participants who provided treatment data had positive urine findings during the study.
A qualitative screen does not quantify how much methamphetamine was used or establish a person’s degree of impairment. Conversely, self-report is not interchangeable with an objective toxicology result. The discordance cannot, by itself, determine whether reporting, timing, detection characteristics or another factor explains the difference.
Vital signs did not change significantly over time, and reported side-effect, anxiety and depression scores decreased. Adverse events nevertheless occurred, including tachycardia and dry mouth; one event followed taking a double dose after a missed dose. The small study cannot establish broad safety or exclude uncommon harms.
Its findings support further investigation rather than a proven treatment effect on methamphetamine use. Attrition and concurrent behavioral interventions further limit interpretation.
The paper illustrates how exposure detection, reported behavior and clinical outcomes answer different questions. None alone supplies an impairment scale. See our analysis of blood results and differing behavior for that distinction in a forensic setting.