New research published in Early Intervention in Psychiatry has found that vitamin D deficiency is associated with more severe symptoms and cognitive deficits in people with schizophrenia.
People with schizophrenia often have low vitamin D levels. This is because patients with schizophrenia are often hospitalized, or the nature of the disorder keeps them from getting proper sun exposure. While vitamin D deficiency is common in schizophrenia, there haven’t been any studies that have explored how low vitamin D levels might affect symptom severity.
Recently, researchers at the University of North Carolina at Chapel Hill helped shed some light on vitamin D’s role in symptom severity in people with first-episode schizophrenia.
The research team analyzed the vitamin D levels of 20 patients with schizophrenia who had their blood drawn as part of two research projects at the university in 2010. The researchers also tested the vitamin D levels of 20 healthy participants for comparison.
To evaluate the relationship between vitamin D status and symptom severity, the patients with schizophrenia were evaluated using the Positive and Negative Syndrome Scale (PANSS).
PANSS consists of an hour long interview in which the severity of the patient’s positive and negative symptoms are each determined with a score from 7-49, where 7 is least severe and 49 is very severe. Positive symptoms are characterized as a distortion or excess of normal function (e.g. delusions, hallucinations, and hostility), while negative symptoms are characterized as a loss of normal function (e.g. anxiety, depression, and disorientation).
After the researchers determined vitamin D levels and PANSS scores, they found:
- The average vitamin D levels did not differ between the patients with schizophrenia and the healthy participants.
- In the schizophrenia group, low vitamin D levels were associated with more severe negative symptoms (P=0.007) and total symptom severity (P=0.02).
- In the schizophrenia group, low vitamin D levels trended toward more severe positive symptoms, although this was not significant (p=0.15).
- Low vitamin D levels were related to more severe cognitive deficits in the group with schizophrenia (P=0.003).
The researchers concluded,
“This study is the first, to our knowledge, to report an association of vitamin D insufficiency and more severe negative symptoms and poorer neurocognitive function in patients with schizophrenia.”
The researchers further added,
“These findings lead us to hypothesize that inadequate vitamin D status may account for some portion of the symptom burden experienced by persons with schizophrenia.”
The small population size and lack of ethnic diversity means that these results cannot be generalized to other populations. With the observational design of this study, we cannot know for sure if low vitamin D levels cause more severe symptoms in those with schizophrenia.
This being a pilot study means we still have a ways to go in the research of vitamin D and symptom severity in schizophrenia. While previous research has shown vitamin D deficiency is common in those with schizophrenia, this is the first study to show that low vitamin D levels may play a role in the burden experienced by people with schizophrenia. Still, we need well designed randomized controlled trials to determine if vitamin D supplementation can improve symptom severity in those with schizophrenia.