Images

Substance use is driven by the pharmacological effects of a drug, which are experienced as reinforcing/rewarding

The interaction between neurocircuitry and behaviour of addiction, divided into binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation, each of which is associated with the activation of certain neurological pathways.

The image shows how alcohol may interact with the neurotransmitter systems of the brain’s reward pathway, by inhibiting GABA signalling in the ventral tegmental area which in turn disinhibits dopaminergic projections to the nucleus accumbens.

Opioid substances mimic the effects of endogenous opioids within the brain, binding to opioid receptors.

Alcohol interacts with neurons within the ventral tegmental area in several ways.

Schematic illustration of how the gut-brain axis may contribute to the spread of alpha-synuclein pathology (adapted from Breen et al 2019).