A new study found that low vitamin D status was significantly associated with increased symptom severity in schizophrenia.
Schizophrenia is a chronic severe mental illness that affects approximately 3.2 million Americans, about 1% of the population. It is characterized by a range of behaviors, including hallucinations, delusions and paranoia.
Hallucinations describe disorders involving the senses, most often occurring as hearing things or voices that do not exist. Delusions refer to odd or unusual beliefs, such as grandiosity or paranoia.
Symptoms of schizophrenia are categorized into two categories: positive and negative symptoms. Positive symptoms are those behaviors that are present in schizophrenia but absent in healthy individuals, such as hallucinations and delusions. Positive formal thought disorder is delusion for those affected by schizophrenia, in which one has disorganized thoughts and speech.
Negative symptoms describe behaviors that are normally present in individuals but are absent in schizophrenic individuals, including poor grooming, stilted language and affective flattening. Affective flattening refers to reduced expression of emotions, manifesting itself as unchanging facial expression, poor eye contact and lack of vocal inflections.
Recent research shows that schizophrenia is caused by a neurodevelopmental defect that disrupts early brain formation. Vitamin D possesses neuroprotective properties, with some research indicating that healthy vitamin D levels may be an essential component for healthy neural development and function. Due to the presence of vitamin D receptors and the enzyme required to activate vitamin D (1-alpha hydroxylase) in the brain, researchers hypothesize that vitamin D may work locally in the brain to influence proper development.
The research on this topic has only just begun. Current research indicates that low vitamin D levels during the prenatal period and early childhood are significantly linked to schizophrenia. One small study found vitamin D status is significantly associated with schizophrenia. Since the study consisted of such a small sample size, researchers wanted to know if they could replicate these results in a larger sample, further illustrating the potential role of vitamin D in schizophrenia.
To do this, the researchers included 80 patients diagnosed with schizophrenia and 74 age and sex matched healthy individuals. The study compared symptom severity to vitamin D status. The Scale for the Assessment of Negative Symptoms (SANS) and the Scale for the Assessment of Positive Symptoms (SAPS) measured severity of symptoms. Higher scores indicate greater severity.
Here is what the researchers found:
- There were no significant differences in vitamin D status between individuals with and without schizophrenia.
- Vitamin D levels were inversely associated with SANS total and affective flattening among schizophrenic patients (p = 0.019, p = 0.004).
- Low vitamin D levels were linked to higher SAPS total, bizarre behavior and positive formal thought disorders scores (p = 0.015, p = 0.009, p = 0.019).
The researchers concluded,
“Our results, show that lower vitamin D levels were related to positive and negative symptom severity and as the vitamin deficiency became greater, patients’ symptom scores increased, suggesting that it is advisable to monitor the vitamin D levels of patients being treated for schizophrenia.”
Clinical trials are needed to determine whether vitamin D supplementation will cause improvement of symptoms among patients with schizophrenia.
Tovey, A. & Cannell, JJ. Vitamin D status linked to severity of schizophrenia. The Vitamin D Council Blog & Newsletter, 2016.