Objective: It is thought that some psychiatric symptoms may have a relevance with the importance of roles played by vitamin B12 and folate in carbon transfer metabolism (i.e. methylation), required for production of serotonin, dopamine, other monoamine neurotransmitters and catecholamines. Also, methylenetetrahydrofolate reductase (MTHFR) is thought to act directly on dopamine neurons to prevent oxidative damage. Dopamine, itself stimulates methylation of phospholipids in the neuronal membrane and this reaction depends on single carbon folate pathway, thereby underlining the importance of the relationship between dopaminergic neurotransmission and single carbon metabolism . Basal ganglia may especially be vulnerable to deficiencies of vitamin B12 as well as folates and those structures are thought to play a role in Attention-Deficit/Hyperactivity Disorder (ADHD).
Methods: This cross-sectional, retrospective study was conducted at the outpatient clinics of Child and Adolescent Psychiatry in the Faculty of Medicine of Abant Izzet Baysal University.. The records of 6074 patients who applied to the study center in between January 2012 and January 2013 were screened for their presenting complaints and those applying for "inattention" and "hyperactivity" were recorded. It was found that 332 patients were referred for those two complaints and with initial diagnosis of ADHD or ADHD-NOS. To be eligible for ADHD or ADHD-NOS, the patients should be diagnosed with semi-structured interviews. MR should be ruled out with Wechsler Intelligence Scale for Children (Revised) or clinical interviews. Patients who were diagnosed in interview to have ADHD according to DSM-IV-TR criteria formed the ADHD group. The ADHD-NOS group was consisting of children and adolescents, who fulfilled ADHD criteria according to symptom counts and dysfunction while reporting an age of onset of 7 or more years or those who did not fulfill the DSM-IV-TR criteria.
Results: It was found that patients diagnosed to have ADHD and ADHD-NOS predisposed to differ in terms of age and TSH concentrations (both being lower in ADHD-NOS), although the differences did not reach significance. In the second step of the analyses, it was found that among the whole sample, IBC correlated negatively with baseline scores on the Turgay-DSM-IV-Based Scale for Disruptive Behavior Disorders (Rho=- 0.59, p=0.03) while Folate levels leaned to correlate negatively with baseline scores on Child Depression Inventory (Rho= -0.43, p=0.06) although not reaching significance. Interestingly, baseline folate levels correlated positively with scores on Scale for Anxiety and Related Disorders (Rho=0.44, p=0.03).
Conclusion: Subtle abnormalities of folate, Vitamin B12 and iron metabolism may correlate with clinical features both among patients with ADHD and ADHD-NOS. Our results should be supported with future studies.