Introduction: Few studies have focused on the long-term effects of the COVID-19 pandemic on mental health. The objective of our work was to evaluate the changes in emotional and behavioral symptoms in patients with neuropsychiatric disorders and the impact on parenting stress 1 year after the first national lockdown. Methods: We enrolled 369 patients aged 1.5–18 years of age referred to the Child and Adolescent Neuropsychiatry Unit of the University Hospital of Salerno (Italy) by their parents. We asked their parents to complete two standardized questionnaires for the assessment of emotional/behavioral symptoms (Child Behavior CheckList, CBCL) and parental stress (Parenting Stress Index, PSI) prior to the pandemic (Time 0), during the first national lockdown (Time 1) and after 1 year (Time 2), and we monitored the changes in symptoms over time. Results: After 1 year from the start of the first national lockdown, we found a significant increase of internalizing problems, anxiety, depression, somatization, and social and oppositional-defiant problems in older children (6–18 years), and a significant increase of somatization, anxiety problems, and sleep problems in younger children (1.5–5 years). We also observed a significant relationship between emotional/behavioral symptoms and parental stress. Conclusion: Our study showed that parental stress levels increased compared to the pre-pandemic months and continues to persist over time, while internalizing symptoms of children and adolescents showed a significant worsening during 1 year follow-up from the first COVID-19 lockdown.