Plan D- Vitamin D supplementation in psychotic disorders: a placebo controlled randomized trial (Preprint)

Abstract

Cognitive impairments and negative symptoms in schizophrenia are associated with poor outcome, and may have common underlying mechanisms, such as psychomotor retardation. Vitamin D is a neuroactive component associated to both cognitive impairments and negative symptoms. The aim of the study is to evaluate the treatment effect of vitamin D supplementation compared to placebo on measures of psychomotor retardation.

The primary objective is to investigate whether vitamin D supplementation is superior to placebo in improving processing speed. The secondary objectives are to investigate whether vitamin D supplementation is superior to placebo in improving negative symptoms, social and physical activity.

Study design: Randomized placebo-controlled double blind trial. Study population: Men and women, aged 18-65 years, diagnosed with a schizophrenia spectrum disorder, in treatment for their disorder at the Division of Mental Health Services at Akershus University Hospital, and with baseline Vitamin D levels below 75 nmol/l. Intervention: Participants will be randomized 1:1 to either vitamin D3 (50µg capsules) or placebo daily for 12 weeks. The medical product or placebo will be given in addition to treatment as usual. Study measures: Cognitive tests for processing speed, symptom assessments for negative symptoms and blood sampling for vitamin D analyses will be performed at baseline and after 12 weeks intervention. During the 12 week intervention period the participants will use a smart phone application (MinDag) for daily self-report of occupational, social- and physical activity, and biweekly self-report of negative symptoms. Study participants will also wear an actigraph (MotionWatch 8 actigraph from CamNtech) for continuous registration of physical activity.

The study is currently recruiting. Primary outcome is change in cognitive performance on the symbol coding test from the Brief assessment of Cognition in Schizophrenia (BACS). Secondary outcomes are change in negative symptoms from the clinician rated Brief negative symptom scale (BNSS), and change in self-reported negative symptoms from the scale Self-assessment of Negative Symptoms (SNS). Secondary outcomes also include change in self-reported social activities from the MinDag app and change in actigraph registered physical activity.

The results from the study will indicate whether vitamin D supplementation could represent a beneficial treatment strategy for impaired processing speed and related symptoms in schizophrenia.

ClinicalTrials.gov identifier NCT05211635.