As of 2014, the underlying causes of schizophrenia are not known with any certainty, according to Mayo Clinic. The disorder tends to run in families, though some cases occur without a family history of the condition, leading researchers to conclude that the disorder is caused by some combination of heredity and the patient's environment.
Whatever the underlying cause, the proximate reason for the symptoms of schizophrenia are believed to be traceable to an imbalance in certain neurotransmitters, specifically dopamine and glutamate, that interfere with the brain's normal operation. According to PsychCentral, structural differences exist between the brains of schizophrenics and those of people with no trace of the disorder. Whether these differences are a cause or effect of schizophrenia is not known for sure. Developmental neurobiologists, researchers who specialize in the way brains develop in fetuses, have suggested that schizophrenia may be the result of fetal brains forming inappropriate connections during in-utero development. In this model, the abnormal connections lie dormant until they are acted upon by the hormonal changes associated with puberty, which then triggers the symptoms of schizophrenia. Regardless of environmental factors, a strong correlation exists between family members with schizophrenia, especially identical twins, and the risk of developing the disorder.