Schizophrenia has long been considered a mystery by much of the mental health community – a complex psychiatric disorder that is caused by biological processes we don’t yet understand. That mystery has made treating schizophrenia more difficult than, say, major depression: we know how serotonin works, and how we increase its levels in the human body. Schizophrenia is a bigger challenge, partly because we don’t understand its cause or causes.
As Gizmodo reports, a landmark study has now identified one of the missing pieces. Previous studies found that a variant in the extended major histocompatibility complex (MHC), a major part of how our immune systems function, was associated with schizophrenia. However, the meaning behind that association wasn’t clear.
But McCarroll’s new study, which looked at the DNA of nearly 29,000 individuals with schizophrenia and 36,000 without, showed that this particular MHC variant causes the expression of a gene known as C4 to go into overdrive.
And it so happens that C4 is present at neuronal synapses, the connections between neurons that transfer chemical and electrical signals in your brain. On a cellular level, too much C4 can reduce the number of synaptic connections, a process known as “synaptic pruning.” On a human-scale, this can lead to schizophrenia.
This discovery doesn’t solve the mystery entirely, but it gives pharmaceutical companies a starting point for developing therapeutics to treat the cognitive impairments of schizophrenia, which have proven far more complicated to treat than other symptoms.
According to The Toronto Star, it will also open the door to early detection:
The study marks a watershed moment, with the potential for early detection and new treatments that were unthinkable just a year ago, according to Steven Hyman, director of the Stanley Center for Psychiatric Research at the Broad Institute at the Massachusetts Institute of Technology.
Hyman, a former director of the National Institute of Mental Health, calls it “the most significant mechanistic study about schizophrenia ever.”
“I’m a crusty, old, curmudgeonly skeptic,” he said. “But I’m almost giddy about these findings.”