Table 1

Participant demographic and clinical characteristics*

CharacteristicPatients (n = 98)Controls (n = 81)p value†
Age, yr40 ± 1239 ± 15NS
Male/female32/6638/43NS
Polygenic risk score for bipolar disorder−3.07 ± 3.07−6.06 ± 4.05< 0.001
Polygenic risk score for schizophrenia−19.52 ± 3.06−21.18 ± 2.27< 0.001
Bipolar disorder subtype (I/II)55/43——
Education level‡3 ± 13 ± 1NS
Montgomery–Åsberg Depression Rating Scale score7 ± 71 ± 2< 0.001
Young Mania Rating Scale score1 ± 20 ± 10.001
Intracranial volume, L1.6 ± 0.21.6 ± 0.2NS
Smoker35150.007
Snuff user1711NS
Body mass index25.7 ± 4.724.1 ± 3.90.017
Age at onset of bipolar disorder, yr19.3 ± 11.2——
Manic episodes, lifetime2 ± 30< 0.001
Depressive episodes, lifetime12 ± 170< 0.001
Comorbidities
 Panic disorder330< 0.001
 Social phobia130< 0.001
 Alcohol misuse1000.002
 Drug misuse900.004
 Eating disorder1200.001
 History of psychosis470< 0.001
 Obsessive–compulsive disorder800.006
 Generalized anxiety disorder1200.001
 Post-traumatic stress disorder30NS
 Attention-deficit/hyperactivity disorder800.006
Medication use
 Antidepressants380< 0.001
 Antiepileptics320< 0.001
 Antipsychotics220< 0.001
 Lithium530< 0.001

  • NS = nonsignificant.

  • ↵* Significance of group differences. Comparisons were performed using t tests and χ2 tests.

  • ↵† Values are mean ± standard deviation or n.

  • ↵‡ Educational achievement was categorized as follows: 1 pre-high school; 2 high school; 3 university (less than 3 years); and 4 university (3 years or longer).