['Oxytocin (OT) has been a candidate for the treatment of autism spectrum disorders (ASD), and the impact of intranasally delivered OT on ASD has been investigated. However, most previous studies were conducted by single-dose administration to adults; and, therefore, the long-term effect of nasal OT on ASD patients and its effect on children remain to be clarified.', 'We conducted a singled-armed, open-label study in which OT was administered intranasally over the long term to eight male youth with ASD (10-14 years of age; intelligence quotient [IQ] 20-101). The OT administration was performed in a stepwise increased dosage manner every 2 months (8, 16, 24\u2009IU/dose). A placebo period (1-2 weeks) was inserted before each step. The outcome measures were autism diagnostic observation schedule--generic (ADOS-G), child behavior checklist (CBCL), and the aberrant behavior checklist (ABC). In addition, side effects were monitored by measuring blood pressure and examining urine and blood samples.', 'Six of the eight participants showed improved scores on the communication and social interaction domains of the ADOS-G. However, regarding the T-scores of the CBCL and the scores of the ABC, we could not find any statistically significant improvement, although several subcategories showed a mild tendency for improvement. Caregivers of five of the eight participants reported certain positive effects of the OT therapy, especially on the quality of reciprocal communication. All participants showed excellent compliance and no side effects.'] Is long-term administration of intranasal oxytocin a safe and promising therapy for early adolescent boys with autism spectrum disorders?