Relationship between negative symptoms and plasma levels of insulin-like growth factor 1 in first-episode schizophrenia and bipolar disorder patients

► We analyze IGF-1 plasma levels in FPE patients during a 1-year follow-up. ► We also assessed putative correlations of IGF-1 levels with clinical symptoms. ► We found a significant elevation in the plasma levels of IGF-1 soon after FPE. ► IGF-1 levels at FPE and in schizophrenia patients correlate with negative symptoms.