Genetics
Genetics play a role in many serious mental health disorders, and one mental health disorder that has a strong heritability rate is schizophrenia. Presumably, individuals who share greater proportions of their DNA with a schizophrenic will have increased risk of developing the disorder. Heritability of this neurodevelopmental disorder is estimated to be approximately seventy-six percent (Hiker, 2018). Although these studies indicate a strong genetic component in schizophrenia, scientists do not know what genes are directly involved. This is a very complicated process because the disorder is both polygenic and pleiotropic (Zheutlin, 2019). Therefore, the common genetic loci for individuals with schizophrenia have been grouped into three broad categories.
One category are genes that code for synaptic proteins involved in neuronal excitability and plasticity. This category would be genes that code for NMDA receptors, cytoskeletal proteins, or long lasting (L type) calcium channels (Iasevoli, 2014). Another category is cell to cell recognition molecules that play a role in synapse formation and stabilization. Synapse formation and stabilization involves genes such as the DISC-1 gene, and Neuregulin 1 (NRG-1) and its receptor erbB-3 (Selemon, 2015). The last category includes other types of structural proteins. These include the peptide FMRP and other related proteins (Iasevoli, 2014). Although we do not know exactly what causes the deficits in schizophrenia, they seem to be related to establishing neuronal synapses, keeping those synapses working, and maintaining all of the molecules at the synapse in their proper location so that the synapse can function typically. Thus, one may conclude that genetic vulnerability that alters neurodevelopment might include developmental deficits in cell differentiation, migration, or synaptogenesis.
