Headache Disorders: Various conditions with the symptom of HEADACHE. Headache disorders are classified into major groups, such as PRIMARY HEADACHE DISORDERS (based on characteristics of their headache symptoms) and SECONDARY HEADACHE DISORDERS (based on their etiologies). (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)Headache Disorders, Primary: Conditions in which the primary symptom is HEADACHE and the headache cannot be attributed to any known causes.Headache: The symptom of PAIN in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of HEADACHE DISORDERS.Migraine Disorders: A class of disabling primary headache disorders, characterized by recurrent unilateral pulsatile headaches. The two major subtypes are common migraine (without aura) and classic migraine (with aura or neurological symptoms). (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)Headache Disorders, Secondary: Conditions with HEADACHE symptom that can be attributed to a variety of causes including BRAIN VASCULAR DISORDERS; WOUNDS AND INJURIES; INFECTION; drug use or its withdrawal.Cluster Headache: A primary headache disorder that is characterized by severe, strictly unilateral PAIN which is orbital, supraorbital, temporal or in any combination of these sites, lasting 15-180 min. occurring 1 to 8 times a day. The attacks are associated with one or more of the following, all of which are ipsilateral: conjunctival injection, lacrimation, nasal congestion, rhinorrhea, facial SWEATING, eyelid EDEMA, and miosis. (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)Tension-Type Headache: A common primary headache disorder, characterized by a dull, non-pulsatile, diffuse, band-like (or vice-like) PAIN of mild to moderate intensity in the HEAD; SCALP; or NECK. The subtypes are classified by frequency and severity of symptoms. There is no clear cause even though it has been associated with MUSCLE CONTRACTION and stress. (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)Trigeminal Autonomic Cephalalgias: Primary headache disorders that show symptoms caused by the activation of the AUTONOMIC NERVOUS SYSTEM of the TRIGEMINAL NERVE. These autonomic features include redness and tearing of the EYE, nasal congestion or discharge, facial SWEATING and other symptoms. Most subgroups show unilateral cranial PAIN.Migraine without Aura: Recurrent unilateral pulsatile headaches, not preceded or accompanied by an aura, in attacks lasting 4-72 hours. It is characterized by PAIN of moderate to severe intensity; aggravated by physical activity; and associated with NAUSEA and / or PHOTOPHOBIA and PHONOPHOBIA. (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)Migraine with Aura: A subtype of migraine disorder, characterized by recurrent attacks of reversible neurological symptoms (aura) that precede or accompany the headache. Aura may include a combination of sensory disturbances, such as blurred VISION; HALLUCINATIONS; VERTIGO; NUMBNESS; and difficulty in concentrating and speaking. Aura is usually followed by features of the COMMON MIGRAINE, such as PHOTOPHOBIA; PHONOPHOBIA; and NAUSEA. (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)Neurology: A medical specialty concerned with the study of the structures, functions, and diseases of the nervous system.Facial Neuralgia: Neuralgic syndromes which feature chronic or recurrent FACIAL PAIN as the primary manifestation of disease. Disorders of the trigeminal and facial nerves are frequently associated with these conditions.Tryptamines: Decarboxylated monoamine derivatives of TRYPTOPHAN.SUNCT Syndrome: A primary headache disorder that is characterized by frequent short-lasting, unilateral, neuralgiform pain attacks in the ocular area, with CONJUNCTIVA fluid-filling and tearing. SUNCT syndrome is usually resistant to treatment.Vascular Headaches: Secondary headache disorders attributed to a variety of cranial or cervical vascular disorders, such as BRAIN ISCHEMIA; INTRACRANIAL HEMORRHAGES; and CENTRAL NERVOUS SYSTEM VASCULAR MALFORMATIONS.Analgesics: Compounds capable of relieving pain without the loss of CONSCIOUSNESS.Questionnaires: Predetermined sets of questions used to collect data - clinical data, social status, occupational group, etc. The term is often applied to a self-completed survey instrument.Indomethacin: A non-steroidal anti-inflammatory agent (NSAID) that inhibits the enzyme cyclooxygenase necessary for the formation of prostaglandins and other autacoids. It also inhibits the motility of polymorphonuclear leukocytes.Bipolar Disorder: A major affective disorder marked by severe mood swings (manic or major depressive episodes) and a tendency to remission and recurrence.Mental Disorders: Psychiatric illness or diseases manifested by breakdowns in the adaptational process expressed primarily as abnormalities of thought, feeling, and behavior producing either distress or impairment of function.Anxiety Disorders: Persistent and disabling ANXIETY.Mood Disorders: Those disorders that have a disturbance in mood as their predominant feature.Diagnostic and Statistical Manual of Mental Disorders: Categorical classification of MENTAL DISORDERS based on criteria sets with defining features. It is produced by the American Psychiatric Association. (DSM-IV, page xxii)Depressive Disorder, Major: Marked depression appearing in the involution period and characterized by hallucinations, delusions, paranoia, and agitation.