Structural and metabolic differentiation between bipolar disorder with psychosis and substance-induced psychosis: An integrated MRI/PET study.

BACKGROUND: Bipolar disorder (BD) may be characterized by the presence of psychotic symptoms and comorbid substance abuse. In this context, structural and metabolic dysfunctions have been reported in both BD with psychosis and addiction, separately. In this study, we aimed at identifying neural substrates differentiating psychotic BD, with or without substance abuse, versus substance-induced psychosis (SIP) by coupling, for the first time, magnetic resonance imaging (MRI) and positron emission tomography (PET). METHODS: Twenty-seven BD type I psychotic patients with (n=10) or without (n=17) substance abuse, 16 SIP patients and 54 healthy controls were enrolled in this study. 3T MRI and 18-FDG-PET scanning were acquired. RESULTS: Gray matter (GM) volume and cerebral metabolism reductions in temporal cortices were observed in all patients compared to healthy controls. Moreover, a distinct pattern of fronto-limbic alterations were found in patients with substance abuse. Specifically, BD patients with substance abuse showed volume reductions in ventrolateral prefrontal cortex, anterior cingulate, insula and thalamus, whereas SIP patients in dorsolateral prefrontal cortex and posterior cingulate. Common alterations in cerebellum, parahippocampus and posterior cingulate were found in both BD with substance abuse and SIP. Finally, a unique pattern of GM volumes reduction, with concomitant increased of striatal metabolism, were observed in SIP patients. CONCLUSIONS: These findings contribute to shed light on the identification of common and distinct neural markers associated with bipolar psychosis and substance abuse. Future longitudinal studies should explore the effect of single substances of abuse in patients at the first-episode of BD and substance-induced psychosis.

Augmentative repetitive Transcranial Magnetic Stimulation (rTMS) in the acute treatment of poor responder depressed patients: a comparison study between high and low frequency stimulation.

BACKGROUND: While the efficacy of repetitive transcranial magnetic stimulation (rTMS) in Major Depressive Disorder (MDD) is well established, the debate is still open in relation to bipolar depression and to a possible different effectiveness of high vs. low stimulation. The present study was aimed to assess and compare the efficacy and tolerability of different protocols of augmentative rTMS in a sample of patients with current Major Depressive Episode (MDE), poor drug response/treatment resistance and a diagnosis of MDD or bipolar disorder. METHODS: Thirty-three patients were recruited in a 4-week, blind-rater, rTMS trial and randomised to the following three groups of stimulation: (1) (n=10) right dorsolateral prefrontal cortex (DLPFC) 1 HZ, 110% of the motor threshold (MT), 420 stimuli/day; (2) (n=10) right DLPFC, 1Hz, 110% MT, 900 stimuli/day; (3) (n=13) left DLPFC, 10Hz, 80% MT, 750 stimuli/day. RESULTS: Twenty-nine patients completed the treatment, showing a significant reduction of primary outcome measures (HAM-D, MADRS and CGI-S total scores: t=8.1, P<0.001; t=8.6, P<0.001; t=4.6, P<0.001 respectively). No significant differences in terms of efficacy and tolerability were found between high vs. low frequency and between unipolar and bipolar patients. Side effects were reported by 21% of the sample. One of the 4 dropouts was caused by a hypomanic switch. CONCLUSIONS: Augmentative rTMS appeared to be effective and well tolerated for the acute treatment of unipolar and bipolar depression with features of poor drug response/treatment resistance, showing a comparable effectiveness profile between protocols of high and low frequency stimulation.