Table 4.

A summary of the main studies showing alteration in GABA in migraine.

Study	Summary of Findings	Paradigm	Sample
Bridge et al. [134]	GABA levels in the occipital cortex were lower in migraineurs than controls.	MRS	13 MA patients and 13 controls.
Bigal et al. [138]	GABA levels were not significantly different in migraineurs and controls. When pooling the MO and MA patients, GABA concentration was lower in individuals with severe headaches in the previous month.	MRS	9 MA patients, 10 MO patients, and 9 controls.
Onderwater et al. [139]	GABA levels increased from interictal towards the preictal state in migraineurs compared with controls in a provoked migraine attack.	MRS	24 MO patients and 13 controls.
Wang et al. [131]	Chronic migraineurs had significantly lower levels of GABA/water and GABA/creatine in the dentate nucleus.	MRS	25 chronic migraine patients, 24 episodic migraine patients, and 16 controls.
Wu et al. [140]	Lower GABA concentration in the anterior cingulate cortex and medial prefrontal lobe in migraineurs than controls.	MRS	28 MO patients and 28 controls.
Chan et al. [141]	Occipital GABA levels were similar between groups.	MRS	9 MA patients, 7 MO patients, and 16 controls.
Zhang et al. [147]	Lower GABA concentration in chronic migraine.GABA/Glx ratio was lower in the chronic than in the episodic group.	MRS	26 patients (episodic migraine = 11; chronic migraine = 15) and 16 controls.
Chan et al. [142]	No significant difference in GABA and glutamate levels were found between groups.	MRS	18 patients with migraine and 18 controls
Vieira et al. [145]	Chronic migraineurs with comorbid depression showed reduced GABA levels.	Cerebrospinal fluid (CSF) analysis	14 chronic migraine patients, with or without depression and 14 controls.
Strmose et al. [143]	No difference was found in GABA/total creatine levels in either the occipital cortex or in the somatosensory cortex.	MRS	14 MA patients and 16 controls.