Increased encoding of aversive stimuli by lateral habenula neurons during Δ9-tetrahydrocannabinol withdrawal.

Hwang E.; Daphne D.; Maddox C.; Zapata A.; Hoffman A.; Lupica C. · Nature communications · 2026

**Background & Methods** This preclinical review examined the role of the lateral habenula (LHb) in negative affective states during Δ9-THC withdrawal using rat models. The study employed calcium photometry and electrophysiology to measure fear conditioning-associated LHb neuronal activity, freezing behavior, and excitatory-inhibitory balance, alongside assessment of GABAergic neurotransmission from basal forebrain and ventral tegmental area inputs. **Key Findings** • Δ9-THC withdrawal increased lateral habenula calcium signals, freezing behavior, and excitatory-inhibitory ratios during fear conditioning, indicating heightened neuronal responsiveness to aversive stimuli. • GABA release was impaired during withdrawal, particularly from basal forebrain-LHb projections, resulting in disinhibition of LHb output neurons and increased excitability of the circuit. • The LHb appears to mediate cannabis withdrawal-associated negative affect through altered GABAergic signaling, providing a mechanistic link between THC cessation and heightened fear and anxiety-like responses. **Dosage & Administration** Not reported. The abstract does not specify THC dosing regimens, duration of exposure, or withdrawal timeline used in the experimental protocol. **Safety & Adverse Effects** Not reported in abstract. The study focused on neurobiological mechanisms rather than characterizing clinical safety outcomes or adverse effects of withdrawal. **Evidence Quality** This is a preclinical animal study with significant translational limitations. Use of rodent models limits direct applicability to human cannabis withdrawal syndrome. The review nature and reliance on mechanistic endpoints (electrophysiology, calcium imaging) rather than behavioral validation in human populations represents a lower level of evidence (approximately Level 4). Key limitations include the inability to assess subjective anxiety and mood changes in animal models, potential species differences in endocannabinoid system function, and lack of investigation into individual differences in withdrawal severity. The findings suggest plausible neural mechanisms but require human clinical validation. Strengths include rigorous neuroscientific methodology and identification of specific circuit dysfunction (basal forebrain-LHb GABAergic impairment) that could inform future therapeutic targets for cannabis use disorder management.

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