Is insulin growth factor-1 the future for treating autism spectrum disorder and/or schizophrenia?

To date, no curative psychopharmacologic treatment exists for the core symptoms of autism spectrum disorder (ASD) as well as for schizophrenia. Bumatenide is a specific antagonist of the first isoform of the Na-K-Cl cotransporter (NKCC1). It is usually used as a diuretic but may also promote a decrease in intraneuronal chloride ion concentration leading to hyperpolarization in neuronal membrane and subsequent decrease in neuronal hyperexcitability. This physiologic effect has been considered to be behind the relative efficacy of bumetanide in improving symptoms of ASD and, to a lesser extent, schizophrenia. However, insulin growth factor-1 (IGF-1) shows the same physiologic effect. In addition, it may improve brain network dysconnectivity which is known to be an important neurobiological feature in ASD and schizophrenia. IGF-1 has started to prove its efficacy in improving symptoms of children with Rett syndrome, a genetic disorder that shares several clinical similarities with ASD. IGF-1 may also improve oxytocin secretion through the enhancement of the transient potential receptor V2 channel function. Accordingly, IGF-1 should be studied as a potential treatment of ASD and other mental disorders characterized with brain dysconnectivity such as schizophrenia.