Using Drosophila adults (usually males only), different paradigms have been used to recapitulate the effects of chronic mild stress; these include a vibration-stress protocol and a chronic unpredictable mild stress (CUMS) protocol. Depression-like behaviors are observed after exposures of 3-10 days, including reduced locomotor, exploratory, and climbing behavior, increased aggressive behavior, and decreased mating ability. Effects upon serotonin and dopamine levels have been assessed. Antidepressants are able to alleviate the depression-like phenotypes: fluoxetine and gamma-oryzanol have been tested using the CUMS protocol; lithium and 5-hydroxy-L-tryptophan have been tested using the vibration-stress protocol; sucrose (which results in elevated 5-HT levels in the brain) is also observed to alleviate depression-like behaviors in the vibration-stress protocol. The roles of the microbiome and dietary proline have also been investigated.
Using a procedure involving exposure to unpredictable mechanical shock, it has been shown that chronic stress induces strong learning and memory deficits that persist for days after treatment. The role of the dopaminergic system in this response has been investigated.
A model of depression based on assessment of 'learned helplessness' as a response to uncontrollable stressful events has also been developed using flies.
[updated May 2022 by FlyBase; FBrf0222196]
Depression (also known as major depression or major depressive disorder) is a psychiatric disorder that affects mood, behavior, and overall health. It causes prolonged feelings of sadness, emptiness, or hopelessness, and a loss of interest in activities that were once enjoyed. People with depression may also have changes in appetite (leading to overeating or not eating enough), changes in sleeping patterns (sleeping too much or not being able to sleep), loss of energy, and difficulty concentrating. [Genetics Home Reference, Depression; 2019.02.06]
