Attention Deficit Hyperactivity Disorder (ADHD) is a prevalent neurodevelopmental disorder, often comorbid with anxiety and depression. Symptom overlap and inconsistent diagnostic criteria contribute to underdiagnosis and misdiagnosis. Among adults, 20–30% report ADHD-like symptoms during screening, with nearly 90% being false positives. Additionally, 20% of children are misdiagnosed with ADHD, leading to unwarranted amphetamine use, which risks cognitive alterations and addiction. The methylenetetrahydrofolate reductase (MTHFR) gene is crucial for folate and homocysteine metabolism. The MTHFR single nucleotide polymorphism (SNP) C677T reduces enzymatic function by 30–60% and several publications report this genetic variant as a risk factor for ADHD, schizophrenia, and bipolar disorder. Despite this, the CDC currently states insufficient evidence to recommend genetic testing or interventions for individuals with this variant. This study evaluates whether the MTHFR C677T SNP correlates with ADHD and anxiety behaviors. Saliva samples from 30 participants were analyzed using loop-mediated isothermal amplification, a technique easily transferable to a clinical setting, for visual detection of the wild-type and mutant genetic variants. Participants completed surveys to collect information on formal diagnoses, ADHD- and anxiety-related behaviors, and demographics. Participants were grouped into two categories, those with behaviors of ADHD and anxiety and those without behaviors. We hypothesized a positive correlation between the C677T SNP and self-reported ADHD and anxiety behaviors. This study’s primary goal is to develop an objective biological tool to aid clinicians in diagnosing ADHD and anxiety. A secondary aim of this study is to bolster support for treating individuals who have the SNP with a folate supplement, which is reported to reduce symptom severity in individuals with ADHD. Due to the heritability of ADHD and anxiety, increased folate and attention to formulation could optimize fetal neurodevelopment, potentially mitigating ADHD symptom severity in offspring.