GRIK1 and pervasive developmental disorder - not otherwise specified: Moreover, GRIK1 alterations were shown to be associated with various neurobehavioral phenotypes in humans, such as anxiety disorders, schizophrenia, bipolar disorder, epilepsy and PDD-NOS (pervasive developmental disorder not otherwise specified) [11–13], as well as with anxiety-like behaviors in GRIK1 knockout mice – due to its regulation of inhibitory circuits in the amygdala [14].