Further evidence for slow binocular rivalry rate as a trait marker for bipolar disorder.

OBJECTIVE: Binocular rivalry refers to a situation where contradictory information is presented simultaneously to the same location of each eye. This leads to the alternation of images every few seconds. The rate of alternation between images has been shown to be slower in euthymic participants with bipolar disorder than in healthy controls. The alternation rate is not uniformly slowed in bipolar disorder patients and may be influenced by clinical variables. The present study examined whether bipolar disorder patients have slower alternation rates, examined the influence of depression and explored the role of clinical variables and cognitive functions on alternation rate. METHOD: Ninety-six patients with bipolar disorder and 24 control participants took part in the study. Current mood status and binocular rivalry performance were analysed with nonparametric tests. A slow and a normal alternation group were created by median split. We subsequently explored the distribution of several clinical variables across these groups. Further, we investigated associations between alternation rate and various cognitive functions, such as visual processing, memory, attention and general motor speed. RESULTS: The median alternation rate was significantly slower for participants with bipolar disorder type I (0.39 Hz) and for participants with bipolar spectrum disorder (0.43 Hz) than for control participants (0.47 Hz). Depression had no effect on alternation rate. There were no differences between participants with bipolar disorder type I and type II and in regard to medication regime and predominance of one rivalry image. There were also no differences in regard to the clinical variables and no significant associations between alternation rate and the cognitive functions explored. CONCLUSION: We replicated a slowing in alternation rate in some bipolar disorder participants. The alternation rate was not affected by depressed mood or any of the other factors explored, which supports views of binocular rivalry rates as a trait marker in bipolar disorder.

"I really don't know whether it is still there": ambivalent acceptance of a diagnosis of bipolar disorder.

Questioning a diagnosis of bipolar disorder is not surprising given the chronic and fluctuating nature of the illness. Qualitative research using thematic analysis was used to derive an understanding of the process patients used to make sense of their diagnosis of bipolar disorder. The findings suggested that receiving a diagnosis was an active process. Factors such as fluctuating moods, changing diagnoses or misdiagnosis, difficulties patients have differentiating self from illness, mistrust in mental health services, and experiences of negative side effects of medication can contribute to ambivalence about the diagnosis and lead to relapse. These findings highlight the need for clinicians to focus on patients' perceptions of bipolar disorder and work with the ambivalence in the process of facilitating greater acceptance. This has the potential for reducing relapses through increased adherence with treatment.

Plasma oxytocin levels in depression and their correlation with the temperament dimension of reward dependence.

Evidence suggests that the neuropeptide oxytocin plays a role in social affiliation. This behaviour may be related more to personality dimensions than specific psychiatric diagnoses. This study investigated the relationship between plasma oxytocin levels and personality dimensions using the Temperament and Character Inventory (TCI) in 60 outpatients with major depression. The strongest correlation was between plasma oxytocin levels and the temperament dimension of Reward Dependence (0.425 Pearson correlation). This suggested that 17% of the variance in plasma oxytocin levels was explained by the Reward Dependence scores. There was a significant positive correlation between plasma oxytocin levels and the Reward Dependence personality dimension.

Thyroid indices and response to fluoxetine and nortriptyline in major depression.

We investigated: (i) the status of thyroid hormones and their clinical correlates in patients with major depression; (ii) changes in thyroid hormone status after treatment with fluoxetine versus nortriptyline; and (iii) whether blunted thyrotropin-stimulating hormone (TSH) response to thyrotropin-releasing hormone (TRH) challenge predicts improvement after 6 weeks of fluoxetine versus nortriptyline treatment. Patients with major depression entering a treatment trial were assessed with the Structured Clinical Interview for DSM-III-R and were rated on the Montgomery-Asberg Depression Rating Scale (MADRS). Blood samples were taken for TSH, thyroxine (T4) and free thyroxine (FT4) measurement, and the maximum TSH response (deltamaxTSH) to a TRH challenge test was undertaken. Patients were then randomly assigned to receive fluoxetine or nortriptyline for six weeks. At 6 weeks, patients repeated the thyroid hormone assessment and completed the MADRS. Mean concentrations of TSH, T4, FT4 and deltamaxTSH were within reference ranges. T4 and FT4 levels decreased significantly after treatment in responders, but not in nonresponders. After treatment, deltamaxTSH concentrations decreased significantly in patients who responded to fluoxetine, and increased in patients who responded to nortriptyline. Patients with deltamaxTSH blunting at pretreatment were more likely to be male, to have higher MADRS scores and have a history of alcohol and drug dependence. Patients with a pretreatment deltamaxTSH of < 3.0 microm/ml showed greater improvement on the MADRS when treated with fluoxetine than if treated with nortriptyline. We observed a decrease in T4 and FT4 in responders to treatment with fluoxetine or nortriptyline. Positive relationships between deltamaxTSH blunting and alcohol and drug abuse and severity of depression were found. Patients with blunted deltamaxTSH responded better to fluoxetine than to nortriptyline. It is suggested that a blunted DmaxTSH may reflect a predominantly serotonergic disturbance in this group of patients with major depression.