Assessment and diagnostic implications
All patients with headache should be evaluated for depression and anxiety. The recommended self-report screening measure for depression is the 9-item depression module of the Patient Health Questionnaire (PHQ-9) and for anxiety, it is the Generalized Anxiety Disorder 7-item scale (GAD-7).20,21 The GAD-7 has adequate sensitivity and specificity for detecting not only GAD but also PTSD, panic disorder, and social phobia.22 A score of 10 or higher on either measure indicates significant symptoms that merit further assessment. Because symptoms such as sleep disturbance, nausea, irritability, muscle tension, and difficulty in concentrating are common to both migraine and affective disorders, differential diagnosis is facilitated by focusing primarily on the core cognitive and emotional symptoms of the suspected psychiatric condition.
In rare cases, headache may be a symptom of a psychiatric disorder.23 “Headaches secondary to psychiatric disorders” are usually distinguished from migraine by headache occurrence only during active phases of the psychiatric condition. Most commonly, headache occurs as one of many unexplained symptoms in a somatization disorder or as a delusion during psychosis, such as that occurring as part of a severe major depressive episode, schizophrenia, or delusional disorder (somatic type). In the case of headache as delusion content, the delusion typically centers on the origin of the head pain (eg, alien insertion, undiagnosed brain tumor despite clear evidence to the contrary). Sufferers are usually women in whom numerous standard therapies have failed and who obtain headache relief only after direct and successful treatment of the psychiatric disorder.
If migrainous headache occurs at times other than during the active phase of the psychiatric illness or fails to remit when the psychiatric symptoms abate, then migraine is the appropriate diagnosis. Assessing the temporal patterning of headache in relation to psychiatric symptoms is most valuable diagnostically. Migraine is also the appropriate differential diagnosis if a psychiatric illness worsens a preexisting headache.
Treatment and management
Pharmacological management of comorbid psychiatric disorders may involve administering a single agent for both migraine and the comorbid disorder or using separate agents for each condition. In clinical practice, monotherapy usually is unrealistic because of differing efficacy and dosing profiles by condition. Preventive migraine medications (eg, propranolol(Drug information on propranolol), amitriptyline(Drug information on amitriptyline), sodium valproate(Drug information on valproate)) are indicated for patients with 4 or more headache days per month or significant functional impairment.
Regarding antidepressants, SSRIs are not efficacious for migraine prevention and SNRIs have not been sufficiently evaluated in large controlled trials.24 The TCA amitriptyline is the only antidepressant or anxiolytic with strong evidence of effectiveness for migraine prevention, but the dosage required to treat affective disturbance is much higher than that used for migraine and often causes sedation and weight gain.25 As such, pharmacological management of migraine and psychiatric disorders typically requires separate agents by condition, in which case, the prescribing physician should be attentive to potential drug interactions and consider using a “staggered” initiation.