Normobaric oxygen treatment for mild-to-moderate depression: a randomized, double-blind, proof-of-concept trial.

Oxygen enriched air may increase oxygen pressure in brain tissue and have biochemical effects even in subjects without lung disease. Consistently, several studies demonstrated that normobaric oxygen treatment has clinical benefits in some neurological conditions. This study examined the efficacy of normobaric oxygen treatment in subjects with depression. In a randomized, double-blind trial, 55 participants aged 18-65 years with mild to moderate depression (had a Hamilton Rating Scale for Depression [HRSD] score of ≥ 8) were recruited to the study from the Southern district in Israel. Participants underwent a psychiatric inclusion assessment at baseline and then were randomly assigned to either normobaric oxygen treatment of 35% fraction of inspired oxygen or 21% fraction of inspired oxygen (room air) through a nasal tube, for 4 weeks, during the night. Evaluations were performed at baseline, 2 and 4 weeks after commencement of study interventions, using the following tools: HRSD; Clinical Global Impression (CGI) questionnaire; World Health Organization-5 questionnaire for the estimation of Quality of Life (WHO-5-QOL); Sense of Coherence (SOC) 13-item questionnaire; and, Sheehan Disability Scale (SDS). A multivariate regression analysis showed that the mean ± standard deviation [SD] changes in the HRSD scores from baseline to week four were - 4.2 ± 0.3 points in the oxygen-treated group and - 0.7 ± 0.6 in the control group, for a between-group difference of 3.5 points (95% confidence interval [CI] - 5.95 to - 1.0; P = 0.007). Similarly, at week four there was a between-group difference of 0.71 points in the CGI score (95% CI - 1.00 to - 0.29; P = 0.001). On the other hand, the analysis revealed that there were no significant differences in WHO-5-QOL, SOC-13 or SDS scores between the groups. This study showed a significant beneficial effect of oxygen treatment on some symptoms of depression.Trial registration: NCT02149563 (29/05/2014).

[PERSONALITY IN EUTHYMIC BIPOLAR PATIENTS AS MEASURED BY SELF-REPORT INSTRUMENTS].

INTRODUCTION: Simple logic would suggest that there should be some endophenotype for bipolar disorder. Possible endophenotypes could include specific variations in personality. Bagby and Ryder summarized the work up to that point by noting that the related personality traits of high neuroticism and harm avoidance seem to be associated with bipolar disorder as well as with unipolar depression, whereas higher novelty seeking may be associated only with bipolar patients. As these parameters are all very sensitive to the affective state, it is critical to examine the literature that pertains specifically to euthymic patients in order to evaluate the extent to which this signifies underlying personality (trait), and not primarily clinical status (state). Several important studies have been published since the Bagby and Ryder paper, which we review here. We restrict our current review to empirical studies which employed both adequate samples of euthymic (to minimize the state/trait dilemma) bipolar patients as well as healthy comparison subjects. This paper is restricted to frequently used explicit measures of personality - that is, self-report questionnaires: the Temperament and Character Inventory (TCI) based on Cloninger's psychobiological theory of temperament and character, the Revised NEO Personality Inventory based on the five-factor model of Costa & McCrae, and the Barratt Impulsiveness Scale (BIS-11) (23). No single dimension of 'personality' reviewed would qualify as a psychological marker for a bipolar disorder. Earlier findings as reviewed by Bagby and Ryder, of higher novelty seeking, were not replicated in these studies. Of the personality traits considered, the most promising candidate for marker or endophenotype would seem to be "impulsivity" as measured by the BIS-II.

Normobaric hyperoxia treatment of schizophrenia.

Several studies of normobaric hyperoxia in neurological conditions have found positive results. The impaired energy metabolism due to mitochondrial dysfunction and frontal lobe hypofunction in schizophrenia might be improved by increasing O2 supply to the brain. Normobaric hyperoxia may be a potential treatment for schizophrenia. Participants in this study, outpatients with chronic schizophrenia and inhabitants of community-based psychiatric institutions (hostels), underwent baseline psychiatric/cognitive assessment and were randomly assigned to either a treatment intervention of oxygen-enriched air inhalation (normobaric hyperoxia of 40% fraction of inspired oxygen) or regular air inhalation (21% fraction of inspired oxygen), through a nasal tube, for 4 weeks. Patients were given the air/oxygen inhalations during the night (mainly while sleeping) for at least 7 hours a night. After completing 4 weeks of treatment, patients were switched (crossed over) to the other treatment intervention. Fifteen patients completed the entire study. Five additional patients completed phase A only. There was significant improvement in total Positive and Negative Symptoms Scale score of patients who received oxygen compared with the control group. There were positive effects of oxygen on memory and attention in neuropsychological performance tests. The effect size is small despite the statistical significance, but the patient group was extremely chronic and severely impaired. These results are a proof of concept, and normobaric hyperoxia should be studied in patients with milder forms of the illness and earlier in the course of illness.