Table 4.

HR with 95% CI of death by suicide among subjects with different combinations of depression and nightmares, compared to subjects without a diagnosis of depression who never or seldom experience nightmares, overall and stratified by gender.

Depression diagnosis	Nightmares	N	Person years	Deaths (%)	P value for mortality rate difference	HR (95% CI)a	HR (95% CI)b
No	Never/seldom	31,643	603,205	32 (0.1)	0.94	1.0 (reference)	1.0 (reference)
No	Sometimes/often/always	7243	136,370	7 (0.1)		1.16 (0.51–2.64)	1.00 (0.44–2.28)
Yes	Never/seldom	1356	25,184	20 (1.5)	0.97	16.5 (9.39–28.9)	12.3 (5.55–27.2)
Yes	Sometimes/often/always	660	12,398	10 (1.5)		20.2 (9.83–41.3)	13.2 (7.25–24.1)
Women
No	Never/seldom	19,585	381,273	9 (0.05)	0.78	1.0 (reference)	1.0 (reference)
No	Sometimes/often/always	5263	102,010	3 (0.06)		1.27 (0.34–4.70)	1.08 (0.29–4.04)
Yes	Never/seldom	936	17,819	8 (0.85)	0.94	19.1 (7.36–49.7)	15.2 (5.67–40.5)
Yes	Sometimes/often/always	517	9910	5 (0.97)		22.0 (7.35–66.1)	13.3 (4.05–43.5)
Men
No	Never/seldom	12,058	221,932	23 (0.19)	0.85	1.0 (reference)	1.0 (reference)
No	Sometimes/often/always	1980	34,360	4 (0.20)		1.11 (0.38–3.20)	0.96 (0.33–2.79)
Yes	Never/seldom	420	7365	12 (2.8)	0.73	15.3 (7.58–30.7)	12.6 (6.08–26.0)
Yes	Sometimes/often/always	143	2488	5 (3.5)		19.4 (7.35–51.0)	12.6 (4.45–35.9)

We used the test-based method to calculate p values.

^aAdjusted for gender when appropriate.

^bAdjusted for gender when appropriate, occupational status, educational status, smoking, sleep duration, hypnotic use, cardiovascular disease, anxiety disorders, and psychotic disorders. Significant HRs are in bold.