Table 2 Summary of Studies Assessing Neuropsychiatric Effects of Vitamin C Deficiency
From: The neuropsychiatric effects of vitamin C deficiency: a systematic review
Study | Number of subjects | Study definition of deficiency in μmol/L and blood component measured | Measurement tool | Outcome |
|---|---|---|---|---|
[21] (Kinsman et al) | 5 | Low group, mean whole blood level: 25 | Minnesota Multiphasic Personality Inventory | Increased scores in social inversion, ‘neurotic triad’ (hypochondriasis, depression, hysteria) |
[24] (Pullar et al) | 139 | Inadequate, plasma: < 50 | Profile of Mood States | Increased total mood disturbance, depression, confusion |
[25] (Marazzi et al) | 129 | Low, serum: <  23 | Inventory of Psychic and Somatic Complaints-Elderly | Higher depression score |
[28] (Pearson et al) | 404 | Plasma: <  23 | Montreal Cognitive Assessment, Warwick–Edinburgh Mental Wellbeing Scale, Mini-International Neuropsychiatric Interview | Higher level of cognitive impairment, no association with depression or well-being |
[27] (Gale et al) | 921 | Mild deficiency, plasma: 11.92 to 27.82 Moderate-to-severe deficiency, plasma: ≤ 11.91 | Hodkinson Abbreviated Mental Test | Statistically significant increased risk for cognitive impairment for moderate-to-severe, but not mild, deficiency |
[29] (Travica et al) | 80 | Deficiency, plasma: <  28 | Modified Mini Mental State Examination, Revised Hopkins Verbal Learning Test, Symbol Digits Modalities Test, Swinburne University Computerized Cognitive Assessment Battery | Poorer outcome on numerous measures of cognitive function |
[22] (Walker) | 7 | Clinical scurvy | n/a | Degree of confusion noted |
[23] (Deligny et al) | 4 | Clinical scurvy | n/a | Intense asthenia in all patients |
[26] (Mitra) | 6 | Clinical scurvy | n/a | Severe depressive state in all patients |