A case-controlled study of serum BDNF, GDNF, and NGF levels in autistic youth with and without bipolar disorder.

BACKGROUND AND AIM: Research on the different aspects of bipolar disorder (BD) in special populations, such as youth with autism spectrum disorder (ASD) is limited. This case-controlled study aimed to investigate the serum levels of brain-derived neurotrophic factor (BDNF), glial-derived neurotrophic factor (GDNF), and nerve growth factor (NGF) in youth with ASD with and without comorbid BD.

METHODS AND PROCEDURES: Forty young subjects (13.47 ± 2.89 years) diagnosed with ASD with comorbid BD were included in the case group, and 40 age/gender-matched subjects with diagnosis of ASD without any mood disorders were included in the control group. The serum levels of BDNF, GDNF, and NGF were measured using enzyme-linked immunosorbent assays. The Childhood Autism Rating Scale (CARS) was used to assess ASD severity in the subjects.

OUTCOMES AND

RESULTS

Serum BDNF levels were significantly lower in the case group than in the control group (p = 0.002). No significant differences were observed in GDNF and NGF levels between the two groups (p > 0.05). The severity of ASD was significantly higher in the case group (p = 0.001).

CONCLUSIONS AND IMPLICATIONS: Low serum BDNF levels may be associated with BD comorbidity in youth with ASD. Given the difficulty in diagnosing BD in this population, serum BDNF levels may be a biomarker associated with the development/diagnosis of BD in youth with ASD. Further studies with larger sample sizes are required to validate these findings.