The condition that Thomas Birdsey has—schizophrenia—is a serious but rare mental health condition, affecting only 0.25% to 0.64% of the population (“Schizophrenia.” National Alliance on Mental Illness). It is characterized by a series of traits, often including hallucinations or delusions. The individual’s understanding of reality is inaccurate: They may hear voices that are not present or believe themselves to be someone other than who they are. Further, people with schizophrenia can also be affected by symptoms similar to those of depression, such as taking little interest in life or disassociating from other people. They may have a flat affect or awkward social skills. They often experience cognitive symptoms, including a medical condition called “anosognosia,” meaning “lack of insight.” This means that the individual does not understand that they are afflicted with an illness.

The disease does not manifest itself until adulthood—typically early twenties for men and between ages 20 and 30 for women. The causes of schizophrenia are complex and still not entirely understood. It has strong genetic and chemical components, meaning that both brain chemistry and inherited genes work in tandem to manifest the disease. Certain environmental factors, such as those that impact the fetus in utero, or outside factors, such as use of hallucinogenic drugs at a very young age, are thought to possibly contribute.