Table 1.

Stability of symptoms between first and second major depressive episode in bipolar disorder

Symptom	Prevalence episode 1	Prevalence episode 2	Agreement (observed)	Agreement (expected)	kappa	Z-score	p-value	Crude OR	95% CI	Adjusted OR	95% CI	OR (> 365 d)	95% CI
Suicidal ideation	18.4	20.4	78.6%	69.9%	0.288	6.963	*	3.59	2.26-5.69**	3.64	2.29-5.80**	3.58	1.88-6.84**
Hypersomnia	36.2	37.9	65.2%	54.9%	0.230	5.555	*	2.25	1.59-3.20**	2.29	1.61-3.26**	2.15	1.33-3.48**
Psychomotor agitation	18.2	17.2	75.8%	69.9%	0.196	4.730	*	1.91	1.15-3.17**	1.94	1.16-3.25**	1.64	0.84-3.23
Depressed mood	76.7	64.0	67.9%	61.1%	0.175	4.450	*	2.02	1.36-3.00**	2.26	1.51-3.40**	1.20	0.68-2.12
Loss of appetite	27.4	25.7	69.0%	62.2%	0.181	4.386	*	1.68	1.12-2.51**	1.62	1.08-2.43**	1.97	1.10-3.53**
Psychomotor retardation	34.1	40.3	64.7%	57.6%	0.167	4.070	*	1.91	1.35-2.72**	1.98	1.39-2.82**	1.63	1.00-2.67
Hyperphagia	18.9	21.8	72.6%	67.2%	0.165	4.004	*	1.86	1.17-2.95**	1.82	1.14-2.91**	1.09	0.59-2.02
Insomnia	32.8	33.9	64.2%	57.4%	0.160	3.860	*	1.93	1.34-2.78**	1.92	1.33-2.77**	2.21	1.33-3.66**
Worthlessness	72.9	71.0	74.2%	70.2%	0.135	3.261	*	1.67	1.13-2.48**	1.67	1.13-2.48**	1.10	0.63-1.92
Poor concentration	68.2	65.0	73.7%	69.9%	0.126	3.043	*	1.76	1.23-2.53**	1.75	1.22-2.52**	1.84	1.11-3.05**
Guilt/rumination	40.8	41.5	62.1%	57.6%	0.107	2.590		1.61	1.15-2.26**	1.61	1.15-2.26**	1.74	1.10-2.76**
Poor energy	85.1	81.7	82.5%	81.4%	0.057	1.403		1.30	0.74-2.31	1.27	0.71-2.26	0.85	0.37-1.92
Loss of interest	89.4	83.3	84.6%	84.7%	-0.011	-0.268		0.96	0.45-2.06	0.95	0.44-2.04	0.50	0.17-1.50
Distractibility	32.8	40.8	67.9%	58.1%	0.235	5.735	*	2.50	1.75-3.57**	2.52	1.76-3.61**	2.27	1.39-3.69**
Flight of ideas	9.4	13.0	80.9%	77.0%	0.172	4.251	*	3.58	1.89-6.76**	3.58	1.89-6.80**	1.86	0.70-4.94
Talkativeness	2.4	4.1	91.9%	90.4%	0.148	3.718	*	1.78	0.85-2.70**	1.78	0.86-2.71**	1.89	0.55-3.24**
Goal-directed activity	1.0	4.3	93.1%	92.8%	0.031	0.882		4.21	0.47-38.01	4.44	0.46-42.37	nc
High-risk behavior	2.2	2.7	93.1%	93.0%	0.025	0.616		nc		nc		nc
Decreased need for sleep	3.3	2.4	93.2%	93.4%	-0.025	-0.609		nc		nc		nc
Hallucinations	1.5	2.6	96.6%	96.0%	0.150	3.752	*	11.36	2.01-64.20**	11.99	2.08-69.08**	55.64	3.02-1026.43**
Delusions	1.4	1.5	98.1%	97.1%	0.343	8.306	*	56.01	10.83-289.69**	83.09	13.86-497.99**	25.24	2.08-305.96**
Psychosis	2.6	3.6	95.2%	94.0%	0.198	4.857	*	11.36	3.25-39.65**	13.21	3.67-47.59**	7.25	0.74-71.32
	Mean (SD)	Mean (SD)				r		Beta	95% CI	Beta	95%CI	Beta	95% CI
% Days anxious	45.5 (40.9)	49.7 (42.0)	–	–	–	0.24	*	0.230	0.15-0.31**	0.22	0.14-0.31**	0.18	0.07-0.28**
Manic symptoms	0.8 (1.0)	0.7 (0.9)	–	–	–	0.21	*	0.175	0.11-0.24**	n/a	n/a	0.11	0.02-0.20**
% Days irritable	36.9 (38.9)	34.0 (37.3)	–	–	–	0.18	*	0.190	0.11-0.28**	0.19	0.10-0.27**	0.25	0.14-0.36**
CGI	4.0 (0.9)	4.0 (0.8)	–	–	–	0.17	*	0.190	0.10-0.28**	n/a	n/a	0.15	0.02-0.28**
Depressive symptoms	5.8 (1.3)	5.8 (1.2)	–	–	–	0.08		0.076	0.00-0.15**	n/a	n/a	0.04	-0.07-0.14

Columns 1 and 2 show the prevalence of each symptom in the first and second major depressive episode, respectively. Columns 3-7 show agreement between these two episodes, in terms of the kappa statistic. Remaining columns depict association between each symptom in the first and second episode, in terms of odds ratio (OR) and 95% confidence interval (CI). ‘Adjusted’ OR refers to adjustment for overall depression severity in terms of symptom burden (i.e., number of syndromal symptoms). ‘OR > 365 days’ refers to analyses of the subset of patients for whom the two visits are separated by at least 365 days, in order to examine the impact of ‘recency’ on symptom similarity.

nc = not calculable (i.e., cells containing zero); CGI = Clinical Global Impression Scale.

^*Bonferonni-corrected p < 0.05 (i.e., p < 0.002).

^**95% CI excludes 1 (i.e., p < 0.05).