New Insights on the Role of Brain Activity in Depression

Increased pretreatment rostral anterior cingulate cortex theta activity represents a nonspecific prognostic marker of treatment outcome in MDD. A multicenter, randomized clinical trial enrolled 248 outpatients, mean age 38 years, without psychosis and with chronic or recurrent MDD who had usable electroencephalographic (EEG) recordings. They were randomized to receive either an 8-week course of sertraline or placebo.

Higher theta activity at both baseline and week 1 predicted greater depressive symptom improvement, even when controlling for clinical and demographic variables previously linked with treatment outcome. The theta marker, in combination with clinical and demographic variables, accounted for an estimated 39.6% of the variance in symptom change.

Clinical Implications: EEGs have the potential to be used in combination with brain imaging and blood tests to help patients who don’t respond to SSRIs find effective treatments more quickly. “When the results from these tests are combined, we hope to have up to 80% accuracy in predicting whether common antidepressants will work for a patient. This research is very likely to alter the mindset of how depression should be diagnosed and treated,” said senior author Madhukar Trivedi, MD, of the University of Texas, Southwestern Medical Center, Dallas, TX.

Source: Pizzagalli DA, Webb CA, Dillon DG. Pretreatment Rostral Anterior Cingulate Cortex Theta Activity in Relation to Symptom Improvement in Depression: A Randomized Clinical Trial. JAMA Psychiatry. 2018;75:547-554.

Clinical Implications: The results suggest that cognitive function may need to be monitored closely in individuals with affective disorders. “People living with depression shouldn't despair-it's not inevitable that you will see a greater decline in cognitive abilities and taking preventative measures such as exercising, practicing mindfulness and undertaking recommended therapeutic treatments, such as cognitive behavior therapy, have all been shown to be helpful in supporting wellbeing, which in turn may help to protect cognitive health in older age,” said lead author Amber John, PhD, of  the University of Sussex in the United Kingdom.

Source: John A, Patel U, Rusted J, et al. Affective problems and decline in cognitive state in older adults: A systematic review and meta-analysis. Psychol Med. 2018;24:1-13.

Older patients with greater symptoms of depression may have structural differences in the brain compared to people without symptoms. A total of 1111 participants, mean age 71 years, mostly Caribbean Hispanic, stroke-free, older adults, had baseline measures of depressive symptoms. All had brain scans, a psychological exam and assessments for memory and thinking skills. Their memory and thinking skills were tested again an average of five years later.

At baseline, 22% of participants had greater depressive symptoms. These symptoms were significantly associated with worse baseline episodic memory in models adjusted for sociodemographic, vascular risk factor, behavioral, and anti-depressive medication variables. The symptoms were also associated with smaller cerebral parenchymal fraction and increased odds of subclinical brain infarcts, after adjustment for sociodemographic, behavioral, and vascular risk factor variables.

Clinical Implications: “Since symptoms of depression can be treated, it may be possible that treatment may also reduce thinking and memory problems. With as many as 25% of older adults experiencing symptoms of depression, it’s important to better understand the relationship between depression and memory problems,” said lead author Adina Zeki Al Hazzouri, PhD, MS, of the University of Miami Miller School of Medicine in Florida. “Our research suggests that depression and brain aging may occur simultaneously, and greater symptoms of depression may affect brain health through small vessel disease.”

Source: Hazzouri AZA, et al. Greater depressive symptoms, cognition, and markers of brain aging. Neurology. 2018;90:e2077-e2085.