Start an SSRI immediately, as the PHQ-9 score of 17 confirms moderate-severe depression severity warranting pharmacological intervention regardless of the substance use history or recovery context.

A PHQ-9 of 17 confirms severity but not etiology. In the context of OUD recovery, the temporal relationship matters for treatment planning. Treating before understanding the etiology may lead to unnecessary medication or missed diagnoses.

Increase the buprenorphine dose to address the depressive symptoms, as depression in OUD recovery typically indicates inadequate opioid receptor coverage and residual withdrawal contributing to the low mood.

Depression is not a standard indication for buprenorphine dose increase. Buprenorphine dose adjustments should be guided by craving control and withdrawal symptoms, not depressive symptom severity.

Assess the temporal relationship between depressive symptoms and recovery to differentiate independent MDD from protracted opioid withdrawal and psychosocial stressors of recovery.

Depression during OUD recovery has multiple potential etiologies: independent MDD (which may have predated or been masked by opioid use), protracted withdrawal (dysphoria, anhedonia, insomnia, and fatigue can persist for months after stabilization), and psychosocial stressors common in recovery (relationship damage, financial consequences, legal issues, identity restructuring). If the depression clearly predated the substance use or persists well beyond the expected withdrawal period with adequate buprenorphine dosing, an independent mood disorder is likely and an SSRI is appropriate and can be safely used with buprenorphine. If the depressive symptoms are primarily protracted withdrawal, they may improve with time and psychosocial support.

Discontinue buprenorphine and reassess the depression in 4-6 weeks, as the medication itself may be causing or worsening the depressive symptoms through opioid receptor modulation effects.

Discontinuing buprenorphine in a patient with OUD risks relapse, which carries far greater morbidity and mortality than depression during stable recovery. Buprenorphine is not a recognized cause of treatment-emergent depression.