Mental health experts used to classify schizophrenia into five main subtypes: paranoid, catatonic, disorganized, undifferentiated, and residual.
But with the 2013 publication of the latest version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), the so-called “bible” of psychiatric diagnoses, these types gave way to what is now called the schizophrenia spectrum.
The basics are still the same: Schizophrenia causes psychosis, which means people who have the disorder have trouble telling what’s real and what’s not. “There’s no major change in the criteria [for diagnosing schizophrenia],” Soonjo Hwang, MD, assistant professor of psychiatry at the University of Nebraska Medical Center, tells Health.
But the new designation of a schizophrenia spectrum rather than different types of schizophrenia may do a better job of describing an entity that is really several diseases. “Schizophrenia is not a single disease,” says psychiatrist William Carpenter, MD, who was chair of the DSM-5 psychotic disorders working group. “It’s a clinical syndrome,” he says, or a collection of signs and symptoms.
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In schizophrenia, different symptom types tend to occur together in different combinations. For instance, “there’s a fairly high association between delusions and hallucinations,” says Dr. Carpenter, who is also a professor of psychiatry and pharmacology at the Maryland Psychiatric Research Center and the University of Maryland School of Medicine. In addition to hallucinations and delusions, disorganized thinking and speech are also common symptoms of schizophrenia.
“You have to have the symptoms for six months or more to get a diagnosis of schizophrenia,” says John Gilmore, MD, professor and vice chair for research in the Department of Psychiatry at University of North Carolina School of Medicine in Chapel Hill.
“There’s a lot of heterogeneity in schizophrenia,” adds Dr. Gilmore. People diagnosed on the schizophrenia spectrum may or may not share symptoms, and how well they function and the severity of their symptoms can vary, says Dr. Carpenter.
Then, there are related conditions. Schizophreniform disorder is two or more schizophrenia symptoms that last more than one month but less than six months. Brief psychotic disorder involves similar symptoms that go on for at least one day but no more than one month.
Schizoaffective disorder is diagnosed using the same criteria as schizophrenia but also adds a mood element, either major depression or mania. “Schizoaffective disorder is between bipolar and schizophrenia,” says Dr. Gilmore. “In the definition, you can have psychotic symptoms during an affective episode, meaning mania or depression, but you also have persistent psychotic symptoms in the absence of mood symptoms.”
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Categorizing schizophrenia along a spectrum doesn’t change treatment. Treatment for schizophrenia is and has been based on symptoms, not classifications, says Dr. Hwang. And doctors have a lot of discretion in choosing exactly which medications they think are best for a specific individual. That makes schizophrenia very different from, say, cancer, where pinpointing a diagnosis is critical in determining the right therapy.
“What’s encouraged with this way of thinking is treating each [symptom] as its own target for clinical assessment and clinical care,” says Dr. Carpenter. Whether a person with schizophrenia has symptoms involving facial expressions, disturbing social relationships, or disrupting normal movement, “then you identify and figure out how to deal with that,” he says.
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