Investigating the jumping to conclusion bias in bipolar disorder.

INTRODUCTION: Hemsley and Garety described the "jumping to conclusions bias" in which patients with delusions may reach unreasonable results with insufficient information. In this study patients with bipolar disorder and healthy volunteers were compared in terms of jumping to conclusions bias using the beads in the jar task. METHODS: 37 patients with DSM-5 diagnosis of bipolar disorder and 30 healthy controls were tested with the Beads Task (BT), Tower of London Test (ToL) and Barrat Impulsiveness Scale (BIS). RESULTS: In the BT, the mean score of DtD (draws to decision) and JTC (jumping to conclusions) scores were not statistically different between the two groups. In the ToL test, the duration of the total execution and the total time were significantly longer in the bipolar group than the control group. BIS scores were significantly higher in the bipolar group. YMRS (Young Mania Rating Scale) scores were not correlated with BT. CONCLUSIONS: This study is the first clinical study to assess the jumping to conclusions bias in patients with bipolar disorder. No JTC bias was detected in bipolar disorder. Further studies may assess JTC in larger samples to determine the effects of clinical state changes, psychotic symptoms, medication and impulsivity.

Perisylvian GABA levels in schizophrenia and bipolar disorder.

The aim of this study is to measure GABA levels of perisylvian cortices in schizophrenia and bipolar disorder patients, using proton magnetic resonance spectroscopy (1H-MRS). Patients with schizophrenia (n=25), bipolar I disorder (BD-I; n=28) and bipolar II disorder (BD-II; n=20) were compared with healthy controls (n=30). 1H-MRS data was acquired using a Siemens 3T whole body scanner to quantify right and left perisylvian structures' (including superior temporal lobes) GABA levels. Right perisylvian GABA values differed significantly between groups [χ2=9.62, df: 3, p=0.022]. GABA levels were significantly higher in the schizophrenia group compared with the healthy control group (p=0.002). Furthermore, Chlorpromazine equivalent doses of antipsychotics correlated with right hemisphere GABA levels (r2=0.68, p=0.006, n=33). GABA levels are elevated in the right hemisphere in patients with schizophrenia in comparison to bipolar disorder and healthy controls. The balance between excitatory and inhibitory controls over the cortical circuits may have direct relationship with GABAergic functions in auditory cortices. In addition, GABA levels may be altered by brain regions of interest, psychotropic medications, and clinical stage in schizophrenia and bipolar disorder.