Do some anxiety disorders belong to the prodrome of bipolar disorder? A clinical study combining retrospective and prospective methods to analyse the relationship between anxiety disorder and bipolar disorder from the perspective of biorhythms

Table 3 Clinical features of disease (continuous variables)

Variables	BD (n = 48)	Atypical (n = 63)	Anxiety (n = 111)	F
Variables	Mean ± SD	Mean ± SD	Mean ± SD	F
Number of onsets	5.50 ± 2.53^a	3.19 ± 1.81	3.29 ± 1.99^b	7.351^**
Age of first onset (years)	22.50 ± 10.69^c	28.67 ± 13.76	30.62 ± 12.32	2.397
Months since diagnosis	64.87 ± 73.35	59.14 ± 60.24	54.84 ± 85.92	0.097
Frequency (number/year)	1.72 ± 2.87	1.15 ± 1.27	1.01 ± 1.54	0.820
Suicidal ideation	2.00 ± 2.07^d	1.76 ± 2.09^e	0.57 ± 1.42	4.996^**

**P < 0.01
^aThe BD group was significantly higher than the atypical group (P = 0.000). ^bThe BD group was significantly higher than the anxiety group (P = 0.000). ^cThe BD group was significantly younger than the anxiety group (P = 0.016). ^dThe BD group was significantly higher than the anxiety group (P = 0.006). ^eThe atypical group was significantly higher than the anxiety group (P = 0.003)

ISSN: 1471-244X