Abstract
Psychotic disorders are known to be associated with elevated dopamine synthesis; yet, nondopamine factors may underlie the manifestation of some psychotic symptoms that are nonresponsive to dopamine-blocking agents. One under-explored nondopamine mechanism is neuroplasticity. We propose an account of the course of psychotic symptoms based on the extensive evidence for dopamine facilitation of Hebbian synaptic plasticity in cortical and subcortical memory systems. The encoding of psychotic experiences in autobiographical memory (AM) is expected to be facilitated in the hyperdopaminergic state associated with acute psychosis. However, once such 'spurious AM of psychosis' (SAMP) is encoded, its persistence may become dependent more on synaptic factors than dopamine factors. Under this framework, the involuntary retrieval of residual SAMP is postulated to play a key role in mediating the reactivation of symptoms with similar contents, as often observed in patients during relapse. In contrast, with active new learning of normalizing experiences across diverse real-life contexts, supported by intact dopamine-mediated salience, well-integrated SAMP may undergo 'extinction', leading to remission. The key steps to the integration of SAMP across psychotic and nonpsychotic memories may correspond to one's 'recovery style', involving processes similar to the formation of 'non-believed memory' in nonclinical populations. The oversuppression of dopamine can compromise such processes. We synthesize this line of evidence into an updated dopamine-gated memory framework where neuroplasticity processes offer a parsimonious account for the recurrence, persistence, and progression of psychotic symptoms. This framework generates testable hypotheses relevant to clinical interventions.