[Iatrogenic psychiatric-like symptoms recognition]

Alterations of Dopamine D2 Receptors and Related Receptor-Interacting Proteins in Schizophrenia: The Pivotal Position of Dopamine Supersensitivity Psychosis in Treatment-Resistant Schizophrenia

Although the dopamine D2 receptor (DRD2) has been a main target of antipsychotic pharmacotherapy for the treatment of schizophrenia, the standard treatment does not offer sufficient relief of symptoms to 20%-30% of patients suffering from this disorder. Moreover, over 80% of patients experience relapsed psychotic episodes within five years following treatment initiation. These data strongly suggest that the continuous blockade of DRD2 by antipsychotic(s) could eventually fail to control the psychosis in some point during long-term treatment, even if such treatment has successfully provided symptomatic improvement for the first-episode psychosis, or stability for the subsequent chronic stage. Dopamine supersensitivity psychosis (DSP) is historically known as a by-product of antipsychotic treatment in the manner of tardive dyskinesia or transient rebound psychosis. Numerous data in psychopharmacological studies suggest that the up-regulation of DRD2, caused by antipsychotic(s), is likely the mechanism underlying the development of the dopamine supersensitivity state. However, regardless of evolving notions of dopamine signaling, particularly dopamine release, signal transduction, and receptor recycling, most of this research has been conducted and discussed from the standpoint of disease etiology or action mechanism of the antipsychotic, not of DSP. Hence, the mechanism of the DRD2 up-regulation or mechanism evoking clinical DSP, both of which are caused by pharmacotherapy, remains unknown. Once patients experience a DSP episode, they become increasingly difficult to treat. Light was recently shed on a new aspect of DSP as a treatment-resistant factor. Clarification of the detailed mechanism of DSP is therefore crucial, and a preventive treatment strategy for DSP or treatment-resistant schizophrenia is urgently needed.

Predictors of antipsychotic dose changes in the CATIE schizophrenia trial

Data from the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) was used with the objective of evaluating factors associated with antipsychotic dose changes. CATIE was a randomized, comparative effectiveness trial for patients with schizophrenia in which a clinician prescribed a double-blind, flexible dose of one of five antipsychotic medications. The mean number of capsules prescribed monthly was evaluated to identify the period following up-titration with the least sample attrition in which dose changes were likely in response to clinical factors. Demographic, efficacy and tolerability variables were evaluated in two regression models predicting a one capsule dose decrease or increase. The mean dose increased to 2.7 capsules over the first 3 months. The post-titration plateau was identified as between 3 and 6 months. Factors associated with dose increases included the Clinical Global Impression Scale at 6 months and change in the Positive and Negative Syndrome Scale between 3 and 6 months. Decreased dosing was associated only with lower patient rated at 6 months global impression of health. Neither tolerability measures, nor body weight was significantly associated with dose changes. In conclusion, dose changes were weakly associated with measures of current or changing clinical status and not affected by measures of side effects.