Low prefrontal perfusion linked to depression symptoms in methadone-maintained opiate-dependent patients

Clinically depressed patients without substance use disorders, compared to controls, exhibit significantly lower resting regional cerebral blood flow (rCBF) in the prefrontal cortex (PFC). In this study, we examined the link between resting rCBF in the PFC and current depressive symptoms in methadone-maintained opiate-dependent (MM) patients with or without major depression.

Arterial spin labeled perfusion fMRI at 3 Tesla was used to measure resting rCBF in 21 MM patients. Perfusion data were analyzed using SPM2. The relationship between Beck Depression Inventory (BDI) score and resting rCBF was examined in a single regression analysis.

The BDI scores ranged between 0 and 18 (m=7.0, S.D.=4.8), and 30% of the sample had mild to moderate depression symptoms according to BDI scores. A negative correlation was observed between BDI scores and relative rCBF in the bilateral ventrolateral prefrontal cortex, and middle frontal gyri.

The inverse relationship between prefrontal paralimbic rCBF and depression scores suggests a link between reduced fronto-limbic activity and depressive symptoms in MM patients. A significant subgroup of opiate-dependent patients has clinical or sub-clinical depression that is often undetected; our data identify brain substrates of depression symptoms that may also be a potential marker of relapse in this population. Treatment strategies targeting these brain regions may improve outcomes in depressed substance abusers.