researchers believe that schizophrenia has a strong biological basis. the neurotransmitter – , which is blocked by antipsychotics, is hypothesized to have a strong tie to the disorder. another neurotransmitter, – , is thought to be related to schizophrenia as well, as drugs like pcp block this transmitter, resulting in symptoms similar to schizophrenia. additional biological evidence is seen in mri data that show that patients with schizophrenia have enlarged – and decreased gray matter.