A controlled study of folate levels in Chinese inpatients with major depression in Hong Kong

Abstract

Background: Although Western and, in particular, British studies have revealed a substantial rate of hypofolatemia in patients with depression, few such studies have been conducted in Asian populations.

Methods: A group of 117 newly admitted inpatients with DSM-III-R major depression and 72 healthy controls underwent blood investigations and psychometric assessments.

Results: Patients had a significantly lower mean serum folate level (24.6+/-10.2 vs. 30.3+/-11.4 nmol/l, P < 0.001) but a higher mean erythrocyte folate level (801.8+/-284.6 nmol/l vs. 699.5+/-248.7 nmol/l, P < 0.01) than control subjects. No patient or control subjects had low folate, while only four patients (3.4%) and six control subjects (8.3%) had low erythrocyte folate. Folate levels were not related to patients' age, duration of illness, Hamilton Depression Rating Scale, Beck Depression Inventory and Global Assessment Scale scores, and prior psychotropic drug usage. Both patients and control subjects revealed a high intake of green vegetables.

Conclusion: Patients' lower serum folate level was likely to be secondary to their depression but, being well in the normal range, should not have aggravated their depressive symptoms. Culturally patterned health beliefs and dietary practices can influence the connection between folate status and depression in different societies.

Limitations: Patients were not drug-free, while the lack of detailed dietary analysis and longitudinal data on folate level and psychiatric outcome tempered the above conclusion.

Clinical relevance: Since normofolatemia is normative in Hong Kong, the routine screening of folate levels in Chinese depressive patients is not indicated. However, a double-blind, placebo-controlled trial may be useful for finding out whether Chinese patients will still benefit from folate pharmacotherapy.