The biochemical basis of relapse and drug response in schizophrenia: review and hypothesis

A Neurophysiological and Neuropsychological Consideration of Mindful Movement: Clinical and Research Implications

In this article, we present ideas related to three key aspects of mindfulness training: the regulation of attention via noradrenaline, the importance of working memory and its various components (particularly the central executive and episodic buffer), and the relationship of both of these to mind-wandering. These same aspects of mindfulness training are also involved in the preparation and execution of movement and implicated in the pathophysiology of psychosis. We argue that by moving in a mindful way, there may be an additive effect of training as the two elements of the practice (mindfulness and movement) independently, and perhaps synergistically, engage common underlying systems (the default mode network). We discuss how working with mindful movement may be one route to mindfulness training for individuals who would struggle to sit still to complete the more commonly taught mindfulness practices. Drawing on our clinical experience working with individuals with severe and enduring mental health conditions, we show the real world application of these ideas and how they can be used to help those who are suffering and for whom current treatments are still far from adequate.

Stimulant drug treatment in childhood-onset schizophrenia with comorbid ADHD: an open-label case series

The administration of psychostimulants to children with psychotic symptoms is controversial. This study reports the stimulant drug response of 5 children, aged 8-15 years, with childhood-onset schizophrenia (COS) and comorbid attention deficit hyperactivity disorder (ADHD). Four COS inpatients were given stimulants for comorbid ADHD after stabilization of psychosis on antipsychotic medication. A fifth COS inpatient received stimulants while still actively psychotic, despite concurrent neuroleptic treatment. Data from the 10-item Brief Conners Teachers Ratings Scale (BCTRS) were examined the week before, and the week after, stimulant addition. A paired t test, conducted using Conners Teachers data from these 4 subjects, indicated significant improvement in ADHD symptoms (p = 0.02). Data obtained from a retrospective chart review indicated no significant worsening of psychosis. The 2 subjects treated with mixed salts of dextroamphetamine sulfate and amphetamine sulfate remained on that medication at 6 months and at the 2-year follow-up. Our results suggest that ADHD comorbid with COS may be safely treated with a stimulant, once the psychosis is stabilized. A systematic investigation of this question may be warranted.

Blood biogenic amines during clozapine treatment of early-onset schizophrenia

The aims of this investigation were to evaluate long-term and short-term effects of clozapine-treatment on plasma biogenic amines and psychopathology measures in adolescents with schizophrenia (DSM-III-R criteria). The long-term study was conducted in a study sample of 40 young patients (age 14-22 years) following a mean of 3.4 years of neuroleptic treatment. During the study, 20 patients received clozapine, and the other 20 patients were treated with standard neuroleptic medications. At the beginning of the open clinical trials, the patients had already been receiving clozapine treatment for 24 +/- 15 months. Assessment of the biochemical and psychopathological measures was performed on six occasions at consecutive 6-week intervals during maintenance treatment with clozapine or conventional neuroleptics. Blood levels of serotonin, 3-methoxy-4-hydroxy-phenylglycol (MHPG), norepinephrine, and epinephrine were significantly higher in clozapine-treated patients than in conventionally treated patients. During long-term treatment, higher serotonin levels were associated with significantly fewer negative symptoms of schizophrenia, whereas higher MHPG levels were correlated with less depression. The short-term effects of clozapine were assessed in a second and independent study sample. After failing on conventional neuroleptics in clinical trials lasting a mean of 1.6 years, 15 inpatients (aged 11-20 years) received clozapine. Weekly ratings of psychopathological symptoms using standard rating scales were performed in parallel to blood samplings for measurements of biogenic amines and serum levels of clozapine. These measures were obtained for 6 weeks during conventional neuroleptic treatment and for 6 weeks during the open-label clozapine trial. Serum levels of serotonin and plasma norepinephrine levels were significantly higher during treatment with clozapine than during pretreatment with typical neuroleptics. A comparison of plasma epinephrine levels in responders (n = 7) and nonresponders (n = 8) to clozapine revealed that response to clozapine can be predicted by epinephrine levels prior to initiation of treatment with clozapine (responders ranging from 32.2 to 90.3 pg/ml; nonresponders ranging from 92.5 to 473.5 pg/ml). Additionally, subjects who responded to clozapine showed increased mean plasma concentrations of MHPG and epinephrine during treatment with this drug in comparison to the levels measured during pretreatment with typical neuroleptic medication. Nonresponders to clozapine failed to show this increase. Finally, in responders to clozapine a negative linear relationship between negative symptoms of schizophrenia and the concentrations of plasma norepinephrine and serum serotonin were observed. In conclusion, our results demonstrate that plasma epinephrine levels prior to initiation of clozapine therapy predict response to this atypical neuroleptic. Our findings derived from short-term and maintenance treatment with clozapine suggest involvement of norepinephrine, epinephrine and serotonin in the therapeutic actions of the atypical neuroleptic clozapine.

Predicting haloperidol treatment response in chronic schizophrenia

The study attempted to identify pretreatment characteristics of chronic schizophrenic patients that would predict remission in psychosis and amount of clinical improvement after treatment with haloperidol. Thirty-five acutely relapsed schizophrenic patients were entered into a blind 6-week treatment protocol. Pretreatment measures were assessed for prediction of both remission status (dichotomous) and for correlations with change in psychopathology (continuous). Later age of onset and higher plasma homovanillic acid values were significant predictors of remission status (model 1). However, higher cerebrospinal fluid levels of 3-methoxy-4-hydroxyphenylglycol, as well as indices of normal neurodevelopment, predicted larger changes in psychopathology. The results indicate that the definition of drug response determines the predictive variables. Dopaminergic activity seems to relate to the ability to reach remission, while noradrenergic activity relates to symptom intensity and reduction. In addition to catecholamine activity, neurodevelopmental changes determine response to haloperidol.

Selected quantitative EEG (QEEG) and event-related potential (ERP) variables as discriminators for positive and negative schizophrenia

Heterogeneity is a major obstacle in the search for biological substrates in schizophrenia. The positive and negative distinction, even if too simplistic, may improve our understanding of underlying processes. Frontostriatal deficits have been related to negative symptoms, while dysfunction of the dominant temporal lobe appears more relevant to the generation of positive symptoms. Despite interactions between the subsystems, different neurophysiological profiles could be expected for patients predominantly affected at each of those levels. We performed discriminant analysis on 10 neurophysiological variables (hypothesis-related) in schizophrenic patients grouped by positive or negative symptoms (PANSS), obtaining a discriminant that correctly classified the sample. The function was then tested in a new sample of patients with schizophrenia, affective psychoses, and controls, classifying subjects with 78% sensitivity and 85% specificity. Our findings suggest that predominantly negative and positive schizophrenics have different neurophysiological profiles, which are consistent with the hypotheses of hypofrontality and temporal lobe dysfunction, respectively. A linear relation between discriminant scores and PANSS ratings might reflect coexisting pathologies or compensatory interactions in the mixed subgroup.

An integrative psychophysiological approach to brain hemisphere functions in schizophrenia

The present paper proposes a new psychophysiological approach to the genesis of positive and negative schizophrenic symptoms. According to this approach, the initial factor in schizophrenic disorders is a functional insufficiency of the right hemisphere which can be determined by early emotional experience in combination with subtle brain damage. This functional insufficiency causes (a) the inability to grasp and select information before its realization; and (b) the inability to produce a polysemantic context which is crucial for creativity, psychological defense, and the restoration of search activity, all of which determine psychophysiological adaptation to the environment. Right hemisphere insufficiency causes left hemisphere hyperactivity as an ineffective attempt to compensate for this functional deficiency. As a result, normal search activity is replaced by artificial search activity which is represented by "positive" symptoms, and which uses the predisposition of the left hemisphere's catecholamine system for its increased activity. The suggestion is made that cognitive impairment in schizophrenia (the inability to use appropriate previous information in relation to current perceptual input) is related to the competition between information processing which requires left hemisphere activity, and the formation of positive symptoms, also based on left hemisphere activity.

Pharmacological manipulations of the alpha 2-noradrenergic system. Effects on cognition

Electrophysiological and neurosurgical lesion studies with experimental animals have implicated the ascending dorsal noradrenergic bundle of the locus coeruleus system in cognitive process such as memory, learning and selective attention. However, it has also been suggested that noradrenaline (norepinephrine) is crucial in certain cognitive functions associated with the frontal lobes, particularly the prevention of distractibility by irrelevant stimuli. The alpha 2-receptors of the prefrontal cortex appear to be of particular importance in this respect. Studies with humans and experimental primates provide substantial support for this view. The aged primate brain is prone to degeneration of the locus coeruleus, as well as profound catecholamine depletion in the prefrontal cortex, and so is ideal for psychopharmacological investigation of the role of noradrenaline in frontal lobe function. Elderly monkeys show deficits in performance of the delayed response task, which can be reversed directly by both the mixed alpha 1/alpha 2-agonist clonidine, the more specific alpha 2-agonist guanfacine and also, indirectly, by the alpha 2-antagonist yohimbine. It is suggested that these results can be explained by an attenuation of the distracting properties of irrelevant stimuli following stimulation of noradrenergic activity. Conversely, distractibility is magnified whenever noradrenergic activity is reduced. This is supported by similar findings in psychopharmacological studies of healthy humans. The exception to this is when the locus coeruleus is likely to be firing, e.g. in times of stress or when novel stimuli are encountered. Clonidine attenuates locus coeruleus firing on such occasions, and so counteracts any beneficial (or deleterious) effects of stress on task performance. alpha 2-Adrenoceptor agents have little therapeutic value in patients with dementia of the Alzheimer's type. However, they may have some clinical use in patients who have a cognitive symptomatology similar to that of patients who have received neurosurgical excisions to the frontal lobes, e.g. deficits in working memory, executive function or focused attention, with relative sparing of episodic short term memory. Patients with Korsakoff's disease, attention deficit disorder or schizophrenia may benefit from treatment with alpha 2-agents. In particular, idazoxan has putative therapeutic effects in patients with a neurodegenerative disorder, namely dementia of frontal type.

Facilins, a novel class of biological factors that facilitate the aortic response to dopamine and other biogenic amines

Biological fluids and tissues extracts were shown to contain biological factors, termed facilins, that facilitate the dopamine-, adrenaline-, and serotonin-mediated aortic contraction at concentrations devoid of any direct effect. Cyproheptadine and phentolamine antagonized the direct contracting effect of biogenic amines, but not the facilitated component of the aortic response thus indicating that the mechanism of action of facilins was unlike that of biogenic amines. Fresh schizophrenics' CSF displayed a stronger facilitating effect than normal CSF on the dopamine-mediated aortic response. This finding, however, was not confirmed with samples kept frozen for prolonged periods of time. Multiple molecular forms of facilins were detected in rabbit serum. Those with a high apparent molecular weight were proteinous and were neither insulin nor other factors known for their contracting effects on the aorta such as epidermal growth factor, transforming growth factor-beta, and platelet-derived growth factor.