Assessment of Objective and Subjective Cognitive Function in Patients With Treatment-Resistant Depression Undergoing Repeated Ketamine Infusions

BACKGROUND

Subanesthetic ketamine infusions can elicit rapid and sustained antidepressant effects, yet the potential cognitive impact of ketamine has not been thoroughly examined. This study measured changes in objective and subjective cognitive function following repeated ketamine treatment.

METHODS

Thirty-eight patients with treatment-resistant depression were administered cognitive assessments before and after undergoing 7 i.v. ketamine infusions (0.5 mg/kg over 40 minutes) within a clinical trial examining the efficacy of single and repeated administrations. Depression severity and perceived concentration were evaluated with the Montgomery-Åsberg Depression Rating Scale (MADRS) and the Quick Inventory of Depressive Symptoms Self-Report.

RESULTS

Twenty-three participants (60.5%) responded after repeated infusions (≥50% decrease in MADRS total scores). We measured significant improvements in several cognitive domains, including attention, working memory, verbal, and visuospatial memory (effect sizes ranging from Cohen d = 0.37-0.79). Cognitive changes were attributed to reduction in depressive symptoms except for improvement in verbal memory, which remained significant after adjustment for change in MADRS total score (P = .029, η p2 = 0.13). Only responders reported improvement in subjective cognitive function with repeated ketamine administration (MADRS item 6, P < .001, d = 2.00; Quick Inventory of Depressive Symptoms Self-Report item 10, P < .001, d = 1.36).

CONCLUSION

A short course of repeated ketamine infusions did not impair neurocognitive function in patients with treatment-resistant depression. Further research is required to understand the potential mediating role of response and remission on improved cognitive function accompanying ketamine treatment as well as to examine longer-term safety outcomes. ClinicalTrials.gov identifier NCT01945047.

Systematic comparison of duration of untreated illness versus duration of untreated psychosis in relation to psychopathology and dysfunction in the Cavan-Monaghan first episode psychosis study (CAMFEPS)

This study systematically compared duration of untreated illness (DUI) with duration of untreated psychosis (DUP) in prediction of impairment at first-episode psychosis and investigated the extent to which these relationships are influenced by premorbid features. The Cavan-Monaghan First Episode Psychosis Study ascertained cases of first-episode psychosis in rural Ireland via all routes to care with limited variations in socioeconomic milieu. Cases were evaluated for DUI and DUP and assessed clinically for psychopathology, neuropsychology, neurology, insight and quality of life, together with premorbid features. Analyses then determined prediction of clinical assessments by DUI versus DUP. The study population consisted of 163 cases of first episode psychosis, among which 74 had a schizophrenia spectrum disorder. Shorter DUI but not DUP predicted less severe positive and general symptoms, while shorter DUP and particularly DUI predicted less severe negative symptoms; neither shorter DUP nor shorter DUI predicted less severe cognitive impairment or fewer neurological soft signs; shorter DUP and DUI predicted increased quality of life; shorter DUI but not DUP predicted greater insight. Only prediction of quality of life was weakened by consideration of premorbid features. Results were generally similar across the two diagnostic groupings. The present findings systematically delineate associations with DUI versus DUP across domains of impairment in first episode psychosis. They suggest that DUI may reflect a more insidious process than DUP and that reduction in DUI may be associated with more consistent and broader diminutions in impairment than for DUP.

Systematic epidemiological and clinical comparisons across all 12 DSM-IV psychotic diagnoses in the Cavan-Monaghan First Episode Psychosis Study (CAMFEPS)

BACKGROUND

Research on psychotic illness is loosening emphasis on diagnostic stringency in favour of including a more dimensionally based conceptualization of psychopathology and pathobiology. However, to clarify these notions requires investigation of the full scope of psychotic diagnoses.

METHODS

The Cavan-Monaghan First Episode Psychosis Study ascertained cases of first episode psychosis across all 12 DSM-IV psychotic diagnoses via all routes to care: public, private or forensic; home-based, outpatient or inpatient. There was no arbitrary upper age cut-off and minimal impact of factors associated with variations in social milieu, ethnicity or urbanicity. Cases were evaluated epidemiologically and assessed for psychopathology, neuropsychology, neurology, antecedent factors, insight and quality of life.

RESULTS

Among 432 cases, the annual incidence of any DSM-IV psychotic diagnosis was 34.1/100 000 of population and encompassed functional psychotic diagnoses, substance-induced psychopathology and psychopathology due to general medical conditions, through to psychotic illness that defied contemporary diagnostic algorithms. These 12 DSM-IV diagnostic categories, including psychotic disorder not otherwise specified, showed clinical profiles that were consistently more similar than distinct.

CONCLUSIONS

There are considerable similarities and overlaps across a broad range of diagnostic categories in the absence of robust discontinuities between them. Thus, psychotic illness may be of such continuity that it cannot be fully captured by operational diagnostic algorithms that, at least in part, assume discontinuities. This may reflect the impact of diverse factors each of which acts on one or more overlapping components of a common, dysfunctional neuronal network implicated in the pathobiology of psychotic illness.

Single, Repeated, and Maintenance Ketamine Infusions for Treatment-Resistant Depression: A Randomized Controlled Trial

(Reprinted with permission from The American Journal of Psychiatry 2019; 176:401-409).

Single and repeated ketamine infusions for reduction of suicidal ideation in treatment-resistant depression

Repeated administration of subanesthetic intravenous ketamine may prolong the rapid decrease in suicidal ideation (SI) elicited by single infusions. The purpose of this secondary analysis was to evaluate reduction in SI with a single ketamine infusion compared with an active control, and prolonged suppression of SI with repeated and maintenance infusions. Thirty-seven participants with treatment-resistant depression (TRD) and baseline SI first received a single ketamine infusion during a randomized, double-blind crossover with midazolam. Following relapse of depressive symptoms, participants received six open-label ketamine infusions administered thrice-weekly over 2 weeks. Antidepressant responders (≥50% decrease in Montgomery-Åsberg Depression Rating Scale [MADRS] scores) received four further open-label infusions administered once-weekly. Changes in SI were assessed with the suicide items on the MADRS (item 10, MADRS-SI) and the Quick Inventory of Depressive Symptomatology-Self Report (item 12, QIDS-SI). Linear mixed models revealed that compared with midazolam, a single ketamine infusion elicited larger reduction in SI (P = 0.01), with maximal effects measured at 7 days postinfusion (P < 0.001, Cohen's d = 0.83). Participants had cumulative reductions in MADRS-SI scores with repeated infusions (P < 0.001), and no further change with maintenance infusions (P = 0.94). QIDS-SI results were consistent with MADRS-SI. Overall, 69% of participants had a complete alleviation of SI following repeated infusions. In TRD, single and repeated ketamine infusions resulted in decreases in SI which were maintained with once-weekly maintenance infusions. This study adds to the growing body of research suggesting ketamine as a possible novel treatment strategy for SI in mood disorders.

Comparative Neuroprotective Effect of Celosia argentea Linn. and Vitamin E on Mercury-induced Oxidative and Histological Parameters of Rat Brain

Mercury contamination of our environment in Nigeria is increasing as mining activity increases. Its exposure causes human toxicological effects which include neurotoxicity through reactive oxygen species. This study investigated the ameliorative effects of the flavonoid-rich aqueous extract of Celosia argentea (AECA) and vitamin E (VitE) in the brain of rats treated with mercuric chloride (HgCl2). Twenty-five adult male Wistar rats were randomized into five treatment groups (n=5). Group 1- control; Group 2- HgCl2 (4 mg/kg); Group 3- AECA (400 mg/kg); Group 4- HgCl2 (4 mg/kg) + AECA (400 mg/kg); Group 5- HgCl2 (4 mg/kg) + VitE (500 mg/kg). All items were administered using an oral cannula daily for 14 days. Behavioural studies were carried out on the 16th day of experiment after which rats were euthanized. Thereafter, gross, haematological and biochemical parameters [malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT)] were assessed. Mercuric chloride significantly (p<0.05) reduced body weight of rats, SOD activity and GSH level but increased MDA level, CAT activity and the number of degenerated neurons in the cerebral cortex relative to control group. Microscopically, HgCl2 induced degeneration of cerebral cortical neurons and Purkinje neurons of the cerebellum. Treatment of HgCl2 and AECA and VitE caused a reversal of these HgCl2-induced alterations. The behavioural and haematological parameters were not significantly affected through the groups. The results suggest Celosia argentea Linn and vitamin E protected against mercury-induced gross, oxidative, cerebral and cerebellar damage. Both AECA and Vitamin E demonstrated neuroprotection in this experiment.

Raffia hookeri Ethanolic Pulp Extract Ameliorated Neuronal Damage and Brain Oxidative Stress Following Mechanical-Induced Traumatic Brain Injury in Rats

Traumatic brain injury (TBI) is a complex process resulting into structural brain damage and functional deficits as a result of an external mechanical force. This study aimed to investigate the possible ameliorative effect of Raphia hookeri ethanol extract (RHEE) on induced acute traumatic brain injury in rats. The choice of the plant was based on its reported anti-oxidative property. Thirty-six female Wistar rats were divided into six groups of six animals each. I: CONTROL - distilled water orally; II: RHEE - 100 mg/kg RHEE; III: Sharp trauma brain injury (STBI); IV: STBI+RHEE; V: Blunt trauma brain injury (BTBI); VI: BTBI+RHEE.  Brain injury was inflicted using modified weight drop technique on experimental day 1 while RHEE was given orally by gavage for 7 days post-injury. Blood was collected serially 24hrs, 72hrs and 7 days post-trauma for full blood count and differentials of the white blood cells. On day nine, rats were euthanized and brain harvested for biochemical and histological analyses. Trauma significantly (p<0.05) reduced the relative brain weight of rats compared with the control. Lymphocyte count increased while neutrophils reduced in all traumatized rats compared with control group. Both BTBI and STBI significantly (p<0.05) elevated MDA and significantly (p<0.05) reduced the level of GSH, the activities of SOD and CAT enzymes compared with control group. Histologically, the extent of haemorrhage into the subarachnoid and brain parenchyma in STBI and BTBI groups was reduced in the BTBI+RHEE and STBI+RHEE groups. Administration of RHEE reduced oxidative damage and ameliorated neuronal damage in sharp and blunt brain injuries.

Single, Repeated, and Maintenance Ketamine Infusions for Treatment-Resistant Depression: A Randomized Controlled Trial

OBJECTIVE

Subanesthetic ketamine doses have been shown to have rapid yet transient antidepressant effects in patients with treatment-resistant depression, which may be prolonged by repeated administration. The purpose of this study was to evaluate the antidepressant effects of a single ketamine infusion, a series of repeated ketamine infusions, and prolongation of response with maintenance infusions.

METHODS

Forty-one participants with treatment-resistant depression completed a single-site randomized double-blind crossover comparison of single infusions of ketamine and midazolam (an active placebo control). After relapse of depressive symptoms, participants received a course of six open-label ketamine infusions administered thrice weekly over 2 weeks. Responders, classified as those participants who had a ≥50% decrease in their scores on the Montgomery-Åsberg Depression Rating Scale (MADRS), received four additional infusions administered once weekly (maintenance phase).

RESULTS

Compared with midazolam, a single ketamine infusion elicited a significantly greater reduction in depressive symptoms at the primary efficacy endpoint (24 hours postinfusion). Linear mixed models revealed cumulative antidepressant effects with repeated infusions and doubling of the antidepressant response rate. Fifty-nine percent of participants met response criteria after repeated infusions, with a median of three infusions required before achieving response. Participants had no further change in MADRS scores during weekly maintenance infusions.

CONCLUSIONS

Repeated ketamine infusions have cumulative and sustained antidepressant effects. Reductions in depressive symptoms were maintained among responders through once-weekly infusions. These findings provide novel data on efficacious administration strategies for ketamine in patients with treatment-resistant depression. Future studies should further expand on optimizing administration to better translate the use of ketamine into clinical settings.

Ameliorative Effects of Raffia hookeri Pulp Extract on Cisplatin-induced Brain Damage and Consequent Neurobehavioural Changes in Wistar Rats

Cisplatin (CIS), a known anticancer drug, has side effects initiated by oxidative damage which hinders its use.Raffia hookeri pulp extract (RHPE), reported to possess antioxidant activity should mitigate cisplatin toxicity. The presentstudy examined the potential of RHPE to reduce brain damage in rats exposed to cisplatin. Forty eight female rats (150 g -220 g) were randomized into four groups (n = 12) viz: Group 1 served as control received distilled water daily, Group 2received 100 mg/kg body weight of RHPE, Group 3 received CIS (7.5 mg/kg body weight, intraperitoneally) as single dose,Group 4 received 100 mg/kg body weight of CIS+RHPE. The RHPE was given orally via gavage for 14 days while the singledose of cisplatin was administered on the eighth day of experiment. Behavioral tests namely: transitions, rearings, groomingsand forelimb grip strength were carried out on 15th day of the experiment after which rats were euthanized followed byhistology and histomorphometry. Cisplatin significantly (p<0.05) reduced the percentage body weight changes, transitions,rearings, groomings and forelimb grip strength compared with the control group, whereas treatment with CIS+RHPEsignificantly (p<0.05) increased these parameters compared with Cisplatin treatment. Cisplatin also caused histologicalalterations of Purkinje neurons, pyramidal neurons of Cornu ammonis3, granule cells and cerebral cortex neurons. Itsignificantly (p<0.05) reduced the diameter of Purkinje (9.1±0.59 µm) compared with control (14.41±0.31 µm) andpyramidal neurons (11.32±0.05 µm) compared with control (17.03±0.54 µm). Rats in the CIS+RHPE had their histologyconsiderably improved compared with those of cisplatin. In conclusion, RHPE reversed the behavioural changes anddemonstrated neuroprotection against CIS-induced behavioural changes and microanatomical alterations of cerebellar,hippocampal and cerebral neurons.

Epidemiological and clinical characterization following a first psychotic episode in major depressive disorder: comparisons with schizophrenia and bipolar I disorder in the Cavan-Monaghan First Episode Psychosis Study (CAMFEPS)

While recent research on psychotic illness has focussed on the nosological, clinical, and biological relationships between schizophrenia and bipolar disorder, little attention has been directed to the most common other psychotic diagnosis, major depressive disorder with psychotic features (MDDP). As this diagnostic category captures the confluence between dimensions of psychotic and affective psychopathology, it is of unappreciated heuristic potential to inform on the nature of psychotic illness. Therefore, the epidemiology and clinical characteristics of MDDP were compared with those of schizophrenia and bipolar disorder within the Cavan-Monaghan First Episode Psychosis Study (n = 370). Epidemiologically, the first psychotic episode of MDDP (n = 77) was uniformly distributed across the adult life span, while schizophrenia (n = 73) and bipolar disorder (n = 73) were primarily disorders of young adulthood; the incidence of MDDP, like bipolar disorder, did not differ between the sexes, while the incidence of schizophrenia was more common in males than in females. Clinically, MDDP was characterized by negative symptoms, executive dysfunction, neurological soft signs (NSS), premorbid intellectual function, premorbid adjustment, and quality of life similar to those for schizophrenia, while bipolar disorder was characterized by less prominent negative symptoms, executive dysfunction and NSS, and better quality of life. These findings suggest that what we currently categorize as MDDP may be more closely aligned with other psychotic diagnoses than has been considered previously. They indicate that differences in how psychosis is manifested vis-à-vis depression and mania may be quantitative rather than qualitative and occur within a dimensional space, rather than validating categorical distinctions.

Effect of adrenaline on glucose uptake in the rabbit small intestine

OBJECTIVES

Previous study had shown that nicotine acts on blood glucose through release of adrenaline. While there are reports on the hyperglyceic effect of adrenaline in rabbits, there is no information on the effect of adrenaline on intestinal glucose uptake of rabbits. The present study was carried out to find out if adrenaline has any effect on glucose uptake in the rabbit small intestine.

MATERIALS AND METHODS

Experiments were carried out on fasted anaesthetized male rabbits. Five groups of rabbits (6 rabbits per group) were studied. A vein draining a segment of the upper jejunum was cannulated for blood flow and venous glucose measurements. The left femoral artery and vein were cannulated for arterial blood sampling and drug infusion respectively. Glucose uptake was calculated as a product of jejunal blood flow and the glucose difference between arterial (A) and venous (V) blood.

RESULTS

The fasting venous blood glucose levels were 151.8 +/- 4.4mg/dl and 164.0 + 2.3mg/dl in Groups I and V that were not given adrenoceptor blockers. The upper jejunum had a resting (or basal) glucose uptake of 38.3 +/- 1.6mg/min in the control group. When adrenaline (2ug/kg) was injected intravenously, arterial blood glucose rose from a basal value of 245.5 +/- 4.6mg/dl to 307.5+4.7mg/dl at the peak of response while venous glucose rose from 151.8+4.4mg/dl to 275.8 +/- 4.2mg/dl at the peak of response. Glucose uptake increased to 107.4 +/- 2.5mg/ min at the peak of response. The hyperglycaemic response to adrenaline injection was abolished by propranolol but not by prazosin indicating that this effect of adrenaline is mediated through beta adrenoceptor. Both prazosin and propranolol reduced considerably adrenaline-induced increase in blood flow and glucose uptake, prazosin being more potent in flow reduction.

CONCLUSION

This study showed that the resting small intestine of rabbits took up large amounts of glucose. The intestinal glucose uptake was markedly increased by adrenaline injection. The response to adrenaline was mediated through alpha and beta adrenoceptors. The responses to adrenaline are different in many respects from those induced by nicotine in rabbits in our earlier study. The reason for the differences is obscure.

Gross morphometric reduction of rats' cerebellum by gamma irradiation was mitigated by pretreatment with Vernonia amygdalina leaf extract

The methanolic extract of Vernonia amygdalina (M) or "bitter leaf" is known for its antioxidant activity, and antioxidants are noted to mitigate radiation damage in tissues. The aim of the present study was to observe the radioprotective effect of M on the cerebellum of gamma irradiated rats using alpha-tocopherol (TOCO) as a reference antioxidant. Forty-two male Wistar rats (n=42) weighing 200-240 g were taken for the study. The study comprised of seven groups, with each group comprising of six (n=6) rats i.e. control, M at 250, and 500 mg/kg/day, radiation only, radiation plus M at 250, and 500 mg/kg/day, and TOCO. After 14 days of treatment administered via oral gavage, rats were irradiated with a single dose of 2.0 Gy of gamma rays on the 15-th day and euthanized the next day. Rats cerebella were removed, fixed in 10% formalin saline, weighed and vernier caliper used to obtain cerebellar dimensions as follows: (i) maximum width, (ii) rostrocaudal dimension, and (iii) dorsoventral extent. Data were analyzed using ANOVA with post-test. Gamma radiation caused a statistically significant reduction of the relative weight of the rats' whole brain, relative weight of the cerebellum, the maximum width, rostrocaudal dimension, and dorsoventral extent of the cerebellum. However, pretreatment with M and TOCO significantly mitigated these effects. This study demonstrated that administration of M and TOCO before 2.0 Gy gamma irradiation reduced significantly the radiation induced gross morphometry changes in rats' cerebellum, suggesting that M may qualify for consideration as a medicinal radioprotector.

Effect of nicotine on glucose uptake in the rabbit small intestine

A technique for measuring glucose uptake in the small intestine of rabbits was developed. Using this technique, the glucose uptake in the resting jejunum of rabbits and the effect of nicotine infusion on glucose uptake were studied. Experiments were carried out on fasted anaesthetized male rabbits. Four groups of rabbits (6 per group) were studied. A vein draining segment of the upper jejunum was cannulated for blood flow and venous glucose measurements. The left femoral artery and vein were cannulated for arterial blood sampling and drug infusion respectively. Glucose uptake was calculated as a product of jejunal blood flow and the (A-V) glucose difference. The fasting blood glucose levels were 101.0 +/- 8.4 mg/dl and 127.0 +/- 11.3 mg/dl before and after anaesthesia respectively. Basal blood glucose was much higher than this following surgery. The upper jejunum had a resting glucose uptake of 24.1 +/- 7.0 mg/min. When nicotine (50 ug/kg) was infused intravenously, blood glucose rose from a basal value of 253.8 +/- 9.5 mg/dl to 379.8 +/- 20.3 mg/dl at the peak of response. Glucose uptake increased to 73.1 +/- 11.3 mg/min at the peak of response. These effects of nicotine are mediated through both beta and alpha adrenoceptors. Comparison with previous studies in dogs and rats showed that different adrenoceptors are involved in nicotine hyperglycaemia in fasted dogs, rats and rabbits.

Neurological signs and involuntary movements in schizophrenia: intrinsic to and informative on systems pathobiology

While it has long been considered whether the pathobiology of schizophrenia extends beyond its defining symptoms to involve diverse domains of abnormality, in the manner of a systemic disease, studies of neuromotor dysfunction have been confounded by treatment with antipsychotic drugs. This challenge has been illuminated by a new generation of studies on first-episode schizophrenia before initiation of antipsychotic treatment and by opportunities in developing countries to study chronically ill patients who have remained antipsychotic naive due to limitations in provision of psychiatric care. Building from studies in antipsychotic-naive patients, this article reviews 2 domains of neuromotor dysfunction in schizophrenia: neurological signs and involuntary movements. The presence and characteristics of neurological signs in untreated vis-à-vis treated psychosis indicate a vulnerability marker for schizophrenia and implicate disruption to neuronal circuits linking the basal ganglia, cerebral cortex, and cerebellum. The presence and characteristics of involuntary movements in untreated vis-à-vis treated psychosis indicate an intrinsic feature of the disease process and implicate dysfunction in cortical-basal ganglia-cortical circuitry. These neuromotor disorders of schizophrenia join other markers of subtle but pervasive cerebral and extracerebral, systemic dysfunction, and complement current concepts of schizophrenia as a disorder of developmentally determined cortical-basal ganglia-thalamo-cortical/cerebellar network disconnectivity.

Reduction of hippocampal CA 1 neurons in Wistar rats following the administration of phenytoin for seven days

This study evaluated the neurotoxic effect of parenteral Phenytoin on the Cornu Ammonis 1 (CA 1) region of the Hippocampus in Wistar rats.Twenty wistar rats were randomized into two groups of ten animals each with the experimental group receiving intraperitoneal Phenytoin at a dose of 25 mg/kg body weight per day for seven days while the control group had sham injection of normal saline at equivalent volume for the same period. Hippocampal sections were processed for histology using routine paraffin sectioning followed by Heamatoxylin and Eosin staining. There was a statistically significant reduction in the mean body weight of the experimental group compared to the control group. The cell density in the stratum pyramidale (per 0.11 mm2 area of the CA 1 region of the Hippocampus) was reduced in the experimental group when compared to the control group. (P<0.05). The mean brain weight in both groups did not differ significantly. Our findings reveal that the administration of parenteral phenytoin at a dose of 25mg/kg body weight per day for seven days in Wistar rats resulted in reduction of the cell density in the stratum pyramidale of the CA 1 subfield of the Hippocampus in Wistar rats and a reduction in the mean body weight.

The effect of dexamethasone, metronidazole and ascorbic acid on the morphological changes induced by gamma rays on the spinal cord of Wistar rats

We studied the effects of dexamethasone, ascorbic acid, and metronidazole on the irradiated spinal cord of Wistar rats. Thirty adult Wistar rats were randomly assigned into 3 groups. Five rats served as the control group. Another group of 5 rats were irradiated in the neural axis with 2.5 Gy of gamma rays. The last group of 20 rats were irradiated and then divided into four subgroups of 5 rats each: one subgroup was administered dexamethasone alone, a second subgroup had metronidazole alone, a third subgroup was treated with dexamethasone and metronidazole combined, and a fourth subgroup had ascorbic acid alone, given intraperitoneally for 7 days before exposure to radiation, and also for 5 days after-irradiation. All irradiated animals demonstrated similar vascular changes in form of splitting of the smooth muscle layers of the arterioles of the anterior spinal arteries. Similarly, all the irradiated spinal cord demonstrated shrinkages as noted in the diminution of the neuronal sizes measured by a microscope with a micrometer embedded in the eye-piece objective. The drugs did not individually protect neurons from damage at the level of our investigation. However, the combination of dexamethasone and metronidazole produced a reduction of the degenerative effect of radiation on the neurons when the post-irradiation diameters of the neurons were compared with the control and those of the other experimental groups. We conclude that gamma ray induced damage in the spinal cord may be ameliorated by combining dexamethasone with metronidazole but not by individual treatment with any of the three drugs.