SLC6A3 and schizophrenia: Given the significant synaptic loss in patients with schizophrenia (SZ) during puberty, we investigated DNA-methylation patterns of key synaptic target molecules: dopamine transporter (DAT), dopamine receptor D2 (DRD2), microtubule-associated protein tau (MAPT), and postsynaptic density protein 95 (PSD95).