Table I.

Astrocyte dysfunction in SUDs and depression.^*

SUDs	Depression
Decreased astrocyte density in PFC and other brain regions (AUDs)	Decreased astrocyte density in PFC and other brain regions
Altered glutamate transporter expression e.g., decreased astrocytic EAAT2/ GLT- 1 in DUDs (cocaine, opioids)	Impaired glutamate transport, e.g., decreased expression of EAAT1/GLAST, EAAT2/GLT-1, EAAT4, and vGluT1
Changes in neurotrophic factors, e.g GDNF, BDNF, and FGF-2/bFGF	Decreased neurotrophic factor production/secretion, e.g., BDNF
Reactive gliosis (DUDs)	Altered glutamate and glutamine levels in several brain regions
Astrocyte-mediated tolerance in DUDs (opioids)	Gliotrophic effects of traditional antidepressants, e.g SSRIs, TCAs
	Gliotrophic effects of experimental antidepressants, e.g riluzole

SUD, substance use disorder; PFC, prefrontal cortex; AUD, alcohol use disorder; EAAT2, excitatory amino acid transporter-2; GLT-1, glial glutamate transporter-1; GDNF, glial derived neurotrophic factor; BDNF, brain derived neurotrophic factor; FGF-2/bFGF, basic fibroblast growth factor-2; DUD, drug use disorder; SSRI, selective serotonin reuptake inhibitor; TCA, tricyclic antidepressant.

^*Italicised text denotes potential convergent mechanisms in SUDs and depressive disorders.