Brain Stimulation in the Treatment of Late-Life Severe Mental Illness Other than Unipolar Nonpsychotic Depression

Late-life mental illness is a growing concern. Current medications have limited efficacy and are associated with safety concerns. A variety of brain stimulation approaches offers alternative treatments. We performed a systematic literature search on the efficacy and safety of brain stimulation in late-life mental illnesses, excluding unipolar nonpsychotic depression. Studies on deep brain stimulation, electroconvulsive therapy (ECT), repetitive transcranial magnetic stimulation (rTMS), and vagal nerve stimulation that enrolled exclusively older adults (≥65 years) or analyzed older adults as a separate group were included. The search identified 1,181 publications, of which 43 met the above inclusion criteria: 24 were related to the treatment of non-unipolar depression (ECT: 21; rTMS: 2; ECT and rTMS: 1), 14 related to dementia (ECT: 7[2 of these studies were also related to depression]; vagal nerve stimulation: 2; rTMS: 4; deep brain stimulation: 1), and 7 to schizophrenia (ECT: 7). These studies reported a high degree of variability in efficacy and safety with promising results in general, particularly in the treatment of dementia and schizophrenia. Most publications were limited by small sample sizes, lack of control conditions, and lack of randomization. Large studies with a randomized controlled design or other designs such as crossover or off-on-off-on are needed. In contrast to the empiric and nonspecific use of ECT, future studies using modalities other than ECT could focus on novel biologically based interventions that target specific circuitry. These interventions could also be combined with other non-brain stimulation treatments for possible synergistic effects.