Family history for chronic headache and drug overuse as a risk factor for headache chronification.

Objectives: To assess whether family history for chronic headache (CH) and drug overuse could represent a risk factor for headache chronification.
Background: Among factors investigated as risk factors for chronification of headache disorders, familial liability for CH and drug overuse has been rarely investigated.
Patients and Methods: A total of 105 consecutive patients with daily or nearly daily headache, and 102 consecutive patients with episodic headache matched by age, sex, and type of headache at onset, underwent a structured direct interview about family history for episodic headache, CH with and without medication overuse, substance abuse/dependence, and psychiatric disorders.
Results: In total, 80 out of 105 patients with CH received a diagnosis of medication overuse headache (MOH), 21 patients were classified as chronic migraine (CM), and 4 as chronic tension-type headache (CTTH) without drug overuse. Some 38.1% of CH patients reported family history for CH vs only 13.7% of episodic headaches (P = .001). Familiality for CH with medication overuse was reported by 25.7% of cases vs 9.8% of controls (P = .0028). A familial history of substance abuse was reported by 20% of patients vs 5.9% of controls (P = .0026). In all, 28.7% of MOH patients reported family history for CH with medication overuse (P = .0014) and 21.2% for substance abuse (P = .002). Relatives of patients with MOH were more likely than control relatives to suffer from CH (OR = 4.19 [95% CI 2.05-8.53]), drug overuse (OR = 3.7 [95% CI 1.66-8.24]), and substance abuse (OR = 4.3 [95% CI 1.65-11.19]). No differences regarding family history for episodic headache and for psychiatric disorders were found. No differences in family history for CH with drugs overuse and for substance abuse were found between CH patients without overuse and controls. Fifteen CH patients reported family history for alcohol abuse (P = .0003).
Conclusions: The significantly increased familial risk for CH, drug overuse, and substance abuse suggests that a genetic factor is involved in the process of headache chronification.