Schizophrenia is a chronic severe mental disorder that affects how a person feels, thinks and acts. People with schizophrenia have a difficult time distinguishing reality from imagination.
The symptoms of schizophrenia are categorized by three types: positive, negative and cognitive. Positive symptoms include hallucinations, delusions, thought disorders and movement disorders. Negative symptoms describe disruptions to normal emotions and behaviors, such as the “flat affect,” which refers to reduced expression of emotions. Negative symptoms also include reduced feelings of pleasure in everyday life, apathy and difficulty engaging in activities. Lastly, cognitive symptoms refer to changes in memories and aspects of thinking, including impaired memory, trouble focusing and poor executive functioning (the ability to understand information and use it to make decisions).
Research has illustrated that vitamin D possesses neuroprotective qualities. Scientific literature reviews have suggested that vitamin D could be an important factor in the central nervous system for healthy neural development and function. Furthermore, cross-sectional studies have illustrated that patients with schizophrenia have lower vitamin D levels compared to healthy controls. However, the influence of vitamin D deficiency on symptom severity in adults with schizophrenia has only begun to be investigated.
A recent study published in the journal Early Prevention in Psychiatry aimed to determine the relationship between vitamin D status and symptom severity among schizophrenic patients. The researchers measured the vitamin D levels of 20 recent onset schizophrenic patients and 20 healthy controls. Each participant underwent neurocognitive testing, focusing on verbal fluency, attention, processing speed, memory and executive functioning. All schizophrenic participants were clinically evaluated for depression in addition to positive and negative schizophrenic symptoms.
Here is what the researchers found:
- There was no significant difference in average vitamin D levels between the schizophrenic and healthy participants (p > 0.05).
- The average vitamin D status of schizophrenic and healthy participants were 28.2 ng/ml and 29.9 ng/ml, respectively.
- Among schizophrenic participants, greater severity of negative symptoms was correlated with lower vitamin D status (r = -0.55, P = 0.012).
- Overall symptom severity and positive symptom severity approached a significant relationship with vitamin D status (r = -0.42, P = 0.07 and r = -0.36, P = 0.12, respectively).
- No relationship was seen between vitamin D status and depressive symptoms.
- More severe cognitive deficits were associated with lower vitamin D levels among schizophrenic patients (r = 0.56, P = 0.019).
The researchers discussed the implications of their study,
“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.”
They went on to state,
“As much of the disability experienced by persons with schizophrenia is related to severity of negative and cognitive symptoms and there are currently no approved pharmacologic methods to treat these symptoms, we hypothesize that correcting vitamin D insufficiency in schizophrenia could fill a critical role.”
The study produced interesting findings, but as the researchers mentioned, the research regarding the role of vitamin D in schizophrenia is still in its infancy. The small sample size limited the study’s strength. More importantly, the study design did not allow the researchers to conclude whether correcting vitamin D deficiency would lead to improved symptoms. Randomized controlled trials are needed to evaluate this.
However, at this point we recommend people with schizophrenia take at least 5,000 IU/day of vitamin D (a dose the Food and Nutrition Board says has never caused problems in adults). Also, if you click on the link below, you can print out this study and take it to your psychiatrist.
Tovey, A. & Cannell, JJ. Recent research discovers vitamin D status linked to severity of schizophrenia. The Vitamin D Council Blog & Newsletter, 2016.