Are migraine and bipolar disorders comorbid phenomena?: findings from a pharmacoepidemiological study using the Norwegian Prescription Database.
OBJECTIVE
Clinical, epidemiological, and, recently, genome-wide linkage and genome-wide association studies suggest migraine and bipolar disorder are comorbid phenomena. The objective of this study was to determine whether there is also evidence that this comorbidity exists by virtue of there being a positive relationship between the prescription of medications used to treat migraine and mood-stabilizing agents using the National Norwegian Prescription Database.


METHODS
Data allowing ascertainment of the concurrence of prescriptions for migraine and mood-stabilizing agents were gleaned from the Norwegian Prescription Database for calendar year 2006, covering the total population (N = 4,640,219). Results were obtained using logistic regression analyses and were expressed by odds ratios (ORs).


RESULTS
A total of 81,225 persons (1.8% of the population) received medications for migraine and 19,517 (0.45%) received a mood-stabilizing agent for a bipolar disorder; 843 persons received both types of medications. The OR expressing the relationship between the concurrent use of both categories of medications was 2.55 (95% confidence interval [CI], 2.38-2.73, P < 0.001, z score = 26.44), significant for all mood stabilizers (lithium: OR = 1.82 [95% CI, 1.58-2.10], P < 0.001, z score = 8.31; carbamazepine: OR = 2.48 [95% CI, 2.01-3.06], P < 0.001, z score = 8.42; valproic acid: OR = 2.26 [95% CI, 1.89-2.70], P < 0.001, z score = 8.96; and lamotrigine: OR = 3.50 [95% CI, 3.14-3.90], P < 0.001, z score = 22.68). The association was significantly higher for men (OR = 3.16 [95% CI, 2.74-3.66], P < 0.001, z score = 15.53) than for women (OR = 2.21 [95% CI, 2.04-2.39], P < 0.001, z score = 19.61) and was most pronounced in younger age groups and for lamotrigine.


CONCLUSIONS
There was a strong positive association between the prescription of medications used to treat migraine and mood-stabilizing agents. This is compatible with the hypothesis that migraine and bipolar disorders are associated with one another.
Moodnet Research Group, Haukeland University Hospital, Bergen, Norway. keti@haukeland.no
Ketil J
KJ
Oedegaard
Steven C
SC
Dilsaver
Oivind
O
Hundal
Trond
T
Riise
Anders
A
Lund
Hagop S
HS
Akiskal
Ole B
OB
Fasmer
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D018692:Antimanic Agents / Q000627:therapeutic use; D001714:Bipolar Disorder / Q000188:drug therapy / Q000453:epidemiology*; D002648:Child; D016208:Databases, Factual / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000188:drug therapy / Q000453:epidemiology*; D009664:Norway / Q000453:epidemiology; D017891:Pharmacoepidemiology; D012737:Sex Factors; D055815:Young Adult
D018692:Antimanic Agents