Table 5.

Associations of folate deficiency (<3 ng/mL) with suicidal behavior in patients with depressive disorder.

Suicidal behavior	Folate level	N patient	N (%) presence of suicidal behavior	Odds ratio (95% confidence interval)
				Unadjusted	Adjusteda
Present previous suicidal attempt	Normal range	1,016	80 (7.9)	Ref	Ref
	Deficiency	78	16 (20.5)	3.02 (1.67–5.48)‡	2.32 (1.18–4.49)*
Higher baseline suicidal severity	Normal range	1,016	322 (31.7)	Ref	Ref
	Deficiency	78	40 (51.3)	2.27 (1.43–3.61)‡	2.23 (1.34–3.69)†
Increased suicidal severity during follow-up	Normal range	819	138 (16.8)	Ref	Ref
	Deficiency	65	17 (26.2)	1.75 (0.98–3.13)	1.42 (0.77–2.64)
Fatal/non-fatal suicidal attempt during follow-up	Normal range	819	29 (3.5)	Ref	Ref
	Deficiency	65	9 (13.8)	4.38 (1.98–9.70)‡	2.84 (1.19–6.77)*

Baseline suicidal severity was defined using the brief psychiatric rating scale (BPRS) suicidality item scores, divided into lower [1 (not present) ~ 3 (mild)] and higher [4 (moderate) ~ 7 (extremely severe)]. Increased suicidal severity was defined as any instance in the increase in BPRS suicidality item score during 12-month pharmacotherapy.

^aAdjusted for age, sex, marital state, religious affiliation, monthly income, atypical feature, number of previous depressive episode, use vitamin supplement, and scores on Hospital Anxiety and Depression Scale-anxiety subscale and Alcohol Use Disorders Identification Test for baseline analyses, plus treatment steps over 12-month pharmacotherapy for follow-up analyses.

^* P < 0.05;

^† P < 0.01;

^‡P < 0.001.