To compare a sample of adolescents with schizophrenia spectrum disorders (SSD) treated with either ECT or antipsychotics (AP) alone at long-term follow-up. Patients diagnosed with SSD (n = 21) treated with ECT due to resistance to AP or catatonia under the age of 18 years (ECT group), were compared to a randomly selected group of patients with SSD treated only with AP (non-ECT group) (n = 21) and matched for age, gender, diagnosis and duration of illness. Baseline data were gathered retrospectively from medical records. Subjects were assessed at follow-up (mean of follow-up period = 5.5 years; range 2-9 years) using several clinical scales such as the Positive and Negative Syndrome Scale (PANSS), the Clinical Global Impression Scale (CGI) and the Global Assessment of Functioning (GAF). Improvement in PANSS positive, negative, general, total and CGI and GAF scores between baseline and follow-up assessment did not differ significantly between groups. At follow-up, no differences were observed for the PANSS negative, CGI and GAF scores between groups, but patients in the ECT group still had higher PANSS total, positive and general scores. ECT treatment followed by AP medication in treatment-resistant SSD or catatonia is at least as effective in the long term as AP alone in non-resistant patients.