Adjunctive L-Methylfolate Tied to Executive Function Gains in Psychiatric Patients

In treatment-experienced psychiatric patients receiving established pharmacotherapy, adjunctive L-methylfolate (Deplin) was linked with significant reductions in overall symptom burden and improvements in executive function, according to retrospective chart review data.
Among 60 patients, initiation of L-methylfolate was associated with a significant incremental reduction in overall symptom burden, with an average treatment effect on the treated (ATT) of -0.14 SD (95% CI -0.20 to -0.08, P<0.0001), reported Joel Young, MD, of MedaData and the Rochester Center for Behavioral Medicine (RCBM) in Michigan, and colleagues.
This was a pooled outcome assessed using the ADHD Symptom and Side Effect Tracking scale (ASSET), the Patient Health Questionnaire 9-item scale (PHQ-9), and the Generalized Anxiety Disorder 7-item scale (GAD-7).
Each individual outcome measure showed improvement, with the largest effect observed in executive function:

• Executive function (ASSET; n=58): paired d -0.50 (95% CI -0.77 to -0.23, P=0.0004)
• Depression (PHQ-9; n=60): paired d -0.30 (95% CI -0.56 to -0.04, P=0.023)
• Anxiety (GAD-7; n=28): paired d -0.39 (95% CI -0.78 to -0.01, P=0.048)

The study was presented at the Neuroscience Education Institute (NEI) Fall Congress in Colorado Springs, Colorado.
“What caught my attention most was the pattern of improvement: patients’ executive-function scores showed the largest and earliest change, with depression and anxiety improving more gradually,” co-author Richard Powell, PhD, JD, also of MedaData and RCBM, told MedPage Today.
“Seeing that pattern in patients who were already receiving psychiatric treatment was encouraging,” Powell added.
Prior clinical research has shown benefits from adjunctive L-methylfolate in patients whose depression responded incompletely to standard antidepressants.
“Our study adds a perspective from everyday psychiatric practice: we followed 60 patients before and during Deplin treatment and examined depression, anxiety, and executive-function scores,” Powell said. “That broader picture gives us useful questions to pursue about where patients may experience improvement.”
L-methylfolate is the biologically active form of folate (vitamin B9) that directly crosses the blood-brain barrier, bypassing enzymatic conversion steps such as MTHFR. Deplin is a prescription medical food formulated for the dietary management of suboptimal folate levels in patients with depression and schizophrenia, intended for use under medical supervision.
“Despite widespread clinical use, the incremental benefit of adjunctive Deplin when added to standard psychiatric treatment, particularly among treatment-experienced patients, has not been well characterized in routine clinical practice,” the authors noted on their poster.

To evaluate routine practice outcomes, the researchers used a within-patient interrupted time-series design spanning 2021 to 2026. Out of 131 identified Deplin-treated charts, 60 patients contributed visits both before and during treatment to form the analysis cohort. The GAD-7 was added to clinical surveys in late 2024, resulting in a smaller sample size (n=28) for the anxiety measure. Demographically, the chart-reviewed cohort was 97.7% white and 1.5% Hispanic/Latino.
Symptom reduction was more pronounced among patients with heavier baseline treatment regimens: each additional pre-Deplin medication class was associated with a 0.118 SD greater improvement (mixed-model moderation, P=0.005).
This finding “raises a useful question about who might benefit most,” noted Powell. “Ultimately, we want to understand whether the changes we see in symptom scores translate into meaningful improvements in patients’ everyday lives.”
Secondary analyses demonstrated significant improvements in vegetative (P=0.006), somatic (P=0.044), and behavioral (P=0.040) dimensions, with no assessed side-effect domains worsening significantly during treatment.
In an exploratory analysis of 23 stimulant-treated patients — an outcome outside the product’s approved dietary management labeling — dose trajectories shifted from +3.4 to -2.5 mg-eq/year following L-methylfolate initiation (P=0.0004), at a baseline median amphetamine-equivalent dose of 26 mg-eq.
“I’d encourage clinicians to keep asking about persistent symptoms and how patients are managing day to day. L-methylfolate may be an option to consider for appropriate patients with an incomplete response to depression treatment,” said Powell.
The study authors highlighted several limitations, emphasizing that regression to the mean remains an alternative explanation in single-arm designs initiated during active symptoms. Because the study was observational and non-randomized, confounding by indication and concurrent regimen adjustments cannot be ruled out. All reported P-values were nominal without multiplicity adjustments.
“Controlled research is needed to clarify how much of the improvement was attributable to L-methylfolate,” Powell concluded.