Stress and Depression Linked With Relapses in MG Patients

Stress and depression are associated with higher relapse rates in people with myasthenia gravis (MG), according to a recent study.

Attention to evidence of either disorder is important for proper patient care, its researchers said.

The study, “Prospective study of stress, depression and personality in myasthenia gravis relapses,” was published in the journal BMC Neurology.

In addition to infections and medication, studies suggest that personality traits, coping mechanisms, stress, and depression can lead to relapses in MG.

Researchers at Toronto General Hospital‘s Neuromuscular Clinic studied 155 MG patients, ages 22 to 85, recruited at their center between March 2017 and July 2018. All underwent tests of disease severity, stress, and depression at recruitment and at six-month followup exams or upon MG relapse.

Tests consisted of the Myasthenia Gravis Impairment Index (MGII) for disease severity, the short version of the Trier Inventory for Assessment of Chronic Stress (TICS) questionnaire, and the Beck’s Depression Inventory – Second Edition (BDI-II). Depression was associated with a BDI-II score of 17 or greater.

Patients also completed the Big 5 Personality Inventory (NEO-PI-Revised), a measure of personality traits, at the study’s start.

Using the MGII score values,  participants were categorized as non-relapsers — either remaining stable or getting better — or as relapsers, meaning those having a relapse or worsening. They were defined as relapsers if their MGII scores increased by more than 5.5 points between a first and second visit.

A total of 33 patients (21.3%) relapsed or worsened throughout the study, while most of the other (66.5%) remained stable. Relapses were associated with higher baseline (initial) scores for depression. Patients who relapsed also had more severe disease as measured by the MGII, and changes in disease severity correlated with changes in the depression score.

Patients with baseline TICS scores under 30 — meaning that they “rarely” had a stressful event — had a 13.9% rate of relapse. With TICS scores between 30 and 59,  this rate increased to 22.6. A relapse rate of 31.6% was seen in patients scoring 60 or higher on TICS, marking those who “often” had a stressful event.

Data also showed 9% of relapsers had diagnoses of depression, anxiety, or panic attacks at the study’s start, compared with 6% of non-relapsers. By the study’s end, 27.3% of relapsers showed symptoms of depression, as did 12.5% of non-relapsers.

Patients who relapsed also had worsening BDI-II scores, but showed no significant change in TICS scores.

Compared to patients without depression, those with depression tended to have been diagnosed with MG at a younger age (39.2 vs. 49.4), were younger at the time of the study — 50.5 vs. 60 years — and showed markedly higher levels of chronic stress, as measured by the TICS scale (61.2 vs 29.6).

Disease duration, the proportion of men and women, and the number of patients using immunosuppressant medications were similar among those with or without depression.

Although depression appeared to be closely tied to disease severity, researchers could not say with certainty that being depressed was a relapse trigger. Rather, they wrote, “we found a positive correlation of depression and disease severity.”

Depression in MG is also associated with early stage of disease, a lack of response to treatment, and the use of corticosteroids, they added. Most study participants were on long-term steroid therapy, which could affect the depression rate.

The researchers found that greater relapse rate, stress, depression and disease severity associated with neuroticism — a tendency toward anxiety, mood swings, self-doubt, and other negative feelings. However, as a limited number of participants had neuroticism, this link warrants caution, the team said.

Openness as a personality trait also correlated with depression and stress, which the researchers found surprising, noting this mostly male patient group had a lower relapse rate. They said that openness may associate with better coping and adaptive strategies that lower the effects of daily stress.

“In summary,” the researchers wrote, “we found that baseline stress levels and increasing depression were associated with higher relapse rates in MG but that personality type did not clearly influence relapse rate.”

“Since emotional factors and personality type may influence MG, attention to these factors might improve care in MG patients,” they added.