Dysregulation of Pdlim5 is proposed to factor into atypical dendritic tree morphology and synaptic connectivity in human neurodevelopmental diseases including schizophrenia, depression, and bipolar disorder (Kato et al., 2005; Horiuchi et al., 2006, 2013; Li et al., 2008; Liu et al., 2008; Zain et al., 2013) consistent with our in vitro studies identifying a regulatory role for Pdlim5 in dendrite morphology (Baumert et al., 2020). This evidence concerns the gene PDLIM5 and major depressive disorder.