Low to moderate alcohol consumption is associated with greater hippocampal volume, decreased intensity of clinical pain, and better sleep quality in fibromyalgia patients, new research shows.

The study, “Low-to-Moderate Alcohol Consumption is Associated With Hippocampal Volume in Fibromyalgia and Insomnia,” was published in Behavioral Sleep Medicine.

Fibromyalgia patients often report fatigue and sleep disruption. In fact, one study demonstrated that 75% of patients with fibromyalgia have symptoms of chronic insomnia. Fibromyalgia and chronic insomnia often occur together and are both associated with increased sensitivity to pain, which can be related back to the hippocampus as it is involved in pain stimuli.

Studies have demonstrated that the volume of the hippocampus is reduced in both fibromyalgia patients and chronic insomnia patients. However, no studies have shown the impact of the hippocampal structure in patients that have both chronic musculoskeletal pain and chronic insomnia.

Alcohol use is of great interest in this area because it conducts a number of interesting activities due to its extensive interactions with a variety of neurotransmitter systems such as inhibiting the GABA (gamma amino butyric acid) receptors and the NMDA (n-methyl d-aspartate) receptors.

Patients with fibromyalgia have high levels of excitatory amino acids that act on NMDA receptors, which is associated with hyperalgesia (increased sensitization to pain) and allodynia (a pain response from a stimulus that does not normally provoke pain).

Inhibiting GABA receptors has been shown to promote sleep and reduce anxiety. Therefore, researchers could hypothesize that alcohol use could help regulate fibromyalgia and insomnia symptoms through inhibition of NMDA and GABA receptors.

Researchers at the University of Florida investigated whether alcohol consumption in fibromyalgia patients both with and without chronic insomnia is associated with differences in the structure of the hippocampus by MRI (magnetic resonance imaging). They also evaluated the effect of alcohol on a number of pain and sleep-related measures.

Forty-one patients with fibromyalgia, of whom 19 had insomnia, were instructed to fill out a paper diary of various parameters related to this study, including sleep, pain, and alcohol, for 14 days. This was followed by a structural MRI to determine the volume of the hippocampus.

Interestingly, an MRI analysis showed there was greater bilateral (two-sided) hippocampal volume in moderate drinkers compared with patients who abstained, which has not been reported before. The study indicates moderate drinkers experienced less clinical pain and better sleep quality.

However, there was no significant correlation between the volume of the hippocampus and sleep or pain-related measures. Therefore, alcohol may affect fibromyalgia symptoms by acting on multiple levels, rather than on the hippocampus alone.

“Individuals with fibromyalgia alone or fibromyalgia and chronic insomnia endorsing low-to-moderate alcohol consumption reported lower pain symptomatology and had significantly larger hippocampi than abstainers,” the authors stated. “Based on these findings, systematic prospective and longitudinal work examining the relationship between drinking pattern and FM/FMI symptomatology is warranted.”