Anxiety and cerebral blood flow

Lower cerebrovascular reactivity in prefrontal cortex and weaker negative functional connectivity between prefrontal cortex and insula contribute to white matter hyperintensity-related anxiety or depression

BACKGROUND

White matter hyperintensities (WMHs) are associated with higher anxiety or depression (A/D) incidence. We investigated associations of WMHs with A/D, cerebrovascular reactivity (CVR), and functional connectivity (FC) to identify potential pathomechanisms.

METHODS

Participants with WMH (n = 239) and normal controls (NCs, n = 327) were assessed for A/D using the Hamilton Anxiety Rating Scale (HAMA) and Hamilton Depression Rating Scale (HAMD). The CVR and FC maps were constructed from resting-state functional MRI. Two-way analysis of covariance with fixed factors A/D and WMH was performed to identify regional CVR abnormalities. Seed-based FC analyses were then conducted on regions with WMH × A/D interaction effects on CVR. Logistic regression models were constructed to examine the utility of these measurements for identifying WMH-related A/D.

RESULTS

Participants with WMH related A/D exhibited significantly greater CVR in left insula and lower CVR in right superior frontal gyrus (SFG.R), and HAMA scores were negatively correlated with CVR in SFG.R (r = -0.156, P = 0.016). Insula-SFG.R negative FC was significantly weaker in WMH patients with suspected or definite A/D. A model including CVR plus FC changes identified WMH-associated A/D with highest sensitivity and specificity. In contrast, NCs with A/D exhibited greater CVR in prefrontal cortex and stronger FC within the default mode network (DMN) and between the DMN and executive control network.

LIMITATIONS

This cross-sectional study requires validation by longitudinal and laboratory studies.

CONCLUSIONS

Impaired CVR in SFG.R and weaker negative FC between prefrontal cortex and insula may contribute to WMH-related A/D, providing potential diagnostic imaging markers and therapeutic targets.

Oxytocin modulates hippocampal perfusion in people at clinical high risk for psychosis

Preclinical and human studies suggest that hippocampal dysfunction is a key factor in the onset of psychosis. People at Clinical High Risk for psychosis (CHR-P) present with a clinical syndrome that can include social withdrawal and have a 20-35% risk of developing psychosis in the next 2 years. Recent research shows that resting hippocampal blood flow is altered in CHR-P individuals and predicts adverse clinical outcomes, such as non-remission/transition to frank psychosis. Previous work in healthy males indicates that a single dose of intranasal oxytocin has positive effects on social function and marked effects on resting hippocampal blood flow. The present study examined the effects of intranasal oxytocin on hippocampal blood flow in CHR-P individuals. In a double-blind, placebo-controlled, crossover design, 30 CHR-P males were studied using pseudo-continuous Arterial Spin Labelling on 2 occasions, once after 40IU intranasal oxytocin and once after placebo. The effects of oxytocin on left hippocampal blood flow were examined in a region-of-interest analysis of data acquired at 22-28 and at 30-36 minutes post-intranasal administration. Relative to placebo, administration of oxytocin was associated with increased hippocampal blood flow at both time points (p = .0056; p = .034), although the effect at the second did not survive adjustment for the effect of global blood flow. These data indicate that oxytocin can modulate hippocampal function in CHR-P individuals and therefore merits further investigation as a candidate novel treatment for this group.

Cerebral Blood Flow Volume Using Color Duplex Sonography in Patients With Fibromyalgia Syndrome

Objectives

This study aims to evaluate cerebral blood flow using color duplex Doppler ultrasonography in patients with fibromyalgia syndrome (FMS).

Patients and methods

The study included 30 female patients with FMS (mean age 42.3 years; range 22 to 59 years) and 30 female healthy controls (mean age 39.6 years; range 22 to 56 years). Color duplex Doppler ultrasonography imaging was performed with an EPIQ 5 unit equipped with a multi-frequency linear probe (3-12 MHz) in the supine position. Severity of pain, fatigue, and the patient's and physician's global assessments of disease were evaluated on a visual analog scale. The Symptom Severity Scale, Hamilton Anxiety Rating Scale, Hamilton Depression Evaluation Scale, and Fibromyalgia Impact Questionnaire were also implemented to assess disease severity.

Results

Cerebral blood flow volume and bilateral internal carotid artery (ICA) and vertebral artery (VA) volumes were not significantly higher in FMS patients compared to controls. Bilateral ICA and VA diameters were similar between FMS patients and controls. Bilateral mean peak systolic velocities and end diastolic velocities in the common carotid arteries, ICAs and VAs were similar in both groups. A significant correlation between symptom severity parameter and the cerebral blood flow volume was noted in FMS patients.

Conclusion

Cerebral blood flow volume, ICA flow, and VA flow do not appear to increase, and are correlated with only Symptom Severity Scale among other clinical parameters reflecting disease severity in patients with FMS.

Anxiety, pCO2 and cerebral blood flow

This study examined the effect of anxiety on cerebral blood flow at different levels of pCO2 in healthy participants (N=29). Three types of breathing were used to manipulate pCO2 in a within-subject threat-of-shock paradigm: spontaneous breathing, CO2-inhalation and hyperventilation resulting in normo-, hyper- and hypocapnia. Transcranial Doppler ultrasonography was used to measure CBF velocity (CBFv) in the right middle cerebral artery, while breathing behavior and end-tidal pCO2 were monitored. During normocapnia, elevated anxiety was clearly associated with increased CBFv. Consistent with the cerebral vasoconstrictive and vasodilating effects of, respectively, hypo- and hypercapnia, we observed a positive linear association between CBFv and pCO2. The slope of this association became steeper with increasing anxiety, indicating that anxiety enhances the sensitivity of CBFv to changes in pCO2. The findings may elucidate conflicting findings in the literature and are relevant for brain imaging relying on regional cerebral blood flow.

How does sport psychology actually improve athletic performance? A framework to facilitate athletes' and coaches' understanding

The popularity of sport psychology, both as an academic discipline and an applied practice, has grown substantially over the past two decades. Few within the realm of competitive athletics would argue with the importance of being mentally prepared prior to an athletic competition as well as the need to maintain that particular mindset during a competitive contest. Nevertheless, recent research has shown that many athletes, coaches, and sporting administrators are still quite reluctant to seek out the services of a qualified sport psychologist, even if they believe it could help. One of the primary reasons for this hesitation appears to be a lack of understanding about the process and the mechanisms by which these mental skills affect performance. Unlike the "harder sciences" of sport physiology and biochemistry where athletes can see the tangible results in themselves or other athletes (e.g., he or she lifted weights, developed larger muscles, and is now stronger/faster as a result), the unfamiliar and often esoteric nature of sport psychology appears to be impeding a large number of athletes from soliciting these important services. As such, the purpose of this article is to provide the reader with a simple framework depicting how mental skills training translates into improved within-competition performance. This framework is intended to help bridge the general "understanding gap" that is currently being reported by a large number of athletes and coaches, while also helping sport psychology practitioners sell their valuable services to individual athletes and teams.

Time course of tetrahydrocannabinol-induced changes in regional cerebral blood flow measured with positron emission tomography

While several studies are available on the immediate effects of marijuana and its active ingredient tetrahydrocannabinol (THC) on regional cerebral blood flow (rCBF), we examined the effects of intravenous infusion of THC on rCBF and behavior over a 120-min. period using positron emission tomography. Indices of rCBF, intoxication and physiology were measured at baseline and 30, 60, 90 and 120 min. after a 20-min. intravenous infusion of 0.15 or 0.25 mg/min. of THC, or placebo given to 47 subjects. The rCBF remained increased up to 120 min. after the high-dose THC infusion. Significant increases were seen in global perfusion and in the frontal, insular and anterior cingulate regions. Changes were greater in the right hemisphere. After the high dose, cerebellar flow was increased at both 30 and 60 min. The anterioposterior ratio of cortical rCBF increased in both hemispheres, and remained significantly greater than in the placebo condition until 120 min. in the right hemisphere. Intoxication peaked at 30 min. and remained elevated at 120 min. THC had significant effects on global CBF and rCBF, and feeling intoxicated accounted for changes in rCBF better than plasma level of THC.

Preliminary findings of simultaneous 18F-FDG and 99mTc-HMPAO SPECT in patients with depressive disorders at rest: differential correlates with ratings of anxiety

The assumption of a dynamic coupling between regional cerebral blood flow (rCBF) and cerebral glucose metabolic rates (rCMRGlu) has been challenged by simultaneous measurements of both. Through the use of a dual-headed gamma camera with a 511-keV collimator applying the double isotope 18F-FDG and 99mTc-HMPAO SPECT technique, the uptake rates of these isotopes can be semi-quantitatively evaluated. Sixteen depressed patients, diagnosed by ICD-10 criteria and assessed with the 17-item Hamilton Rating Scale for Depression (HRSD), were studied. Based on the severity of HRSD-rated anxiety (item 10: low=1-21; high=3-4), two eight-patient subgroups were formed and compared with 12 age- and handedness-matched healthy control subjects. As regions of interest, we selected areas implicated in the neuroanatomy of anxiety and depression: hippocampus (hippo), basal ganglia (BG) and gyri temporales superiores (G.t.s.). In the control subjects, a significant statistical coupling between rCBF and rCMRGlu was revealed by the Spearman correlation coefficient only in left hippo and left BG. Patients in the low-anxiety subgroup demonstrated a marked dynamic coupling bilaterally for the G.t.s., while patients in the high-anxiety subgroup showed a significant statistical correlation of rCBF and rCMRGlu only in the left G.t.s. These findings indicate that a dynamic coupling between blood flow and glucose metabolism exists only in distinct brain regions, and that the depressive illness has an uncoupling effect on this correlation in the left BG. Furthermore, our results suggest that the HRSD anxiety score might interact with the underlying depressive illness to influence the relationship of rCBF and rCMRGlu.

Brain activation in PTSD in response to trauma-related stimuli

BACKGROUND

Repetitive recall of traumatic memories and chronic intermittent hyperarousal are characteristic of posttraumatic stress disorder (PTSD). Hyperarousal and memory dysfunction implicates "limbic" brain regions, including the amygdaloid complex, hippocampal formation, and limbic cortex, such as the orbitofrontal and anterior cingulate areas. To investigate the neurobiologic role of these brain regions in PTSD, we measured regional cerebral blood flow in PTSD with single photon emission computerized tomography (SPECT) during a symptom provocation paradigm.

METHODS

Fourteen Vietnam veterans with PTSD, 11 combat control subjects, and 14 normal control subjects were studied with [99mTc]HMPAO in two sessions 48 hours apart: one session after exposure to white noise and the other following exposure to combat sounds. Skin conductance, heart rate, and subjective experience were recorded at the time of the studies.

RESULTS

Activation for all three groups occurred in the anterior cingulate/middle prefrontal gyrus. Activation in the region of the left amygdala/nucleus accumbens was found in PTSD patients only. Deactivation was found in all three groups in the left retrosplenial region.

CONCLUSIONS

These findings implicate regions of the "limbic" brain, which may mediate the response to aversive stimuli in healthy individuals and in patients suffering from PTSD.

Mood state and cerebral metabolism in persons with age-associated memory impairment

People undergoing medical procedures sometimes experience feelings that may influence the results. In this study, we explore the relationship between changes in mood state self-ratings and cerebral glucose metabolism during positron emission tomography (PET) in persons with age-associated memory impairment (mean age 59.4 +/- 9.8 years). Brain regions of interest involved in both mood and memory were examined. Mood ratings of increased boredom correlated significantly with mesial temporal and parietal asymmetry and decreased parietal metabolism. Mood ratings of increased fatigue correlated with basal ganglia asymmetry and the right basal ganglia and left mesial temporal metabolism. These findings suggest that subjective mood state changes during PET may influence metabolism in brain regions implicated in emotion and memory function in people with age-related memory complaints.

Cerebral glucose utilization is reduced in second test session

Cerebral glucose utilization was higher during the first positron emission tomography (PET) session than during the second session, as assayed using the PET [18F]fluorodeoxyglucose method in male human volunteers. This difference was due largely to data from subjects with low-trait anxiety, since subjects with high anxiety showed similar metabolism in both PET sessions. High-anxiety subjects showed greater right/ left ratios of cerebral metabolism than low-anxiety subjects, particularly during the second PET session. These findings suggest that the level of anxiety may be an important variable to consider in PET studies using multiple sessions.

Intracranial and extracranial blood flow during acute anxiety

While large numbers of studies are available on anxiety and cerebral blood flow (CBF), little is known about their relationship to extracranial (forehead) flow. The participants were 24 generalized anxiety disorder (GAD) patients and 26 normal volunteers. A randomized, between groups, repeated measures design was used to evaluate changes in cerebral blood flow. Measurements of CBF, forehead skin perfusion and ratings of anxiety and physiologic indices were made under resting conditions and during anxiety induction with epinephrine or saline infusions, given under double-blind conditions while subjects inhaled room air or 5% CO2. These subjects were divided into three groups; those with decreased anxiety, those with mild anxiety, and those with more severe anxiety increase. Subjects with severe anxiety showed least hypercarbic CBF increase (indicating cerebral vasoconstriction) and maximal increase in forehead skin perfusion. Those with minimal anxiety had most hypercarbic cerebral vasodilation and least increase in forehead skin perfusion. Forehead skin perfusion correlated positively with anxiety levels, and negatively with hypercarbic cerebral vasodilation. In animals, sympathetic activation limits hypercapnic cerebral vasodilation. Thus, the restricted hypercapnic cerebral vasodilation during severe anxiety may be mediated through cervical sympathetic fibers which innervate cerebral vessels.

Cerebral vasodilation and vasoconstriction associated with acute anxiety

A randomized, between-groups, repeated measures design was used to evaluate changes in cerebral blood flow (CBF), rating scales, and physiologic indices under resting conditions, during 5% CO2 inhalation in combination with epinephrine or saline infusions, in generalized anxiety disorder patients and controls. Subjects were divided into those with decreased anxiety and mild and more severe anxiety increase. The first group was found to have most pronounced CBF increase during CO2 inhalation, with the second group showing less marked increase, and the last group the least increase. In animals, sympathetic activation limits hypercapnic cerebral vasodilation. Thus, the restricted hypercapnic cerebral vasodilation during severe anxiety may be mediated through cervical sympathetic fibers, which innervate cerebral vessels.

Acute changes in cranial blood flow after cocaine hydrochloride

Cerebral blood flow (CBF) was measured with the 133Xenon inhalation technique and forehead skin flow with laser Doppler, before and twice after 0.3 milligram/kilogram of cocaine hydrochloride and a placebo given intravenously to six cocaine abusers, during two visits, separated by a minimum of one week. After cocaine, subjects showed significant increases in intoxication and tension. Systolic blood pressure and pulse rate also increased significantly after the drug but not after the placebo. CBF, with and without correction for end-tidal CO2, showed increases in left and right hemisphere after cocaine. The CBF increase was maximal in frontal, central and parietal regions. CBF changes correlated only with changes in a rated level of intoxication. Forehead skin flow did not change after cocaine or placebo. In habitual cocaine abusers, 0.3 mg/kg of cocaine, given intravenously produced increased CBF and no changes in forehead skin flow.

Mood effects on limbic blood flow correlate with emotional self-rating: a PET study with oxygen-15 labeled water

Positron emission tomography was used to study the effects of experimentally controlled mood states on cerebral blood flow (CBF), measured with the quantitative equilibrium infusion method and 15O-labeled water. Twenty-seven brain regions in each hemisphere were assessed in 16 normal subjects. CBF and heart rate were measured during happy and sad mood induction, and during two nonemotional control conditions: sex differentiation and resting baseline. Valence-specific effects of mood on CBF were obtained for subcortical, but not for frontal-temporal or control regions. CBF increased in left amygdala and decreased in right amygdala during sad mood relative to the averaged control conditions. These changes correlated with shifts toward negative affect. Correlations were opposite for subcortical (negative affect associated with lower left hemispheric CBF) compared with frontal-temporal cortical regions. Results support limbic involvement in regulating emotional states and suggest some reciprocity between subcortical and frontal-temporal regulation of emotional experience.

Regional cerebral blood flow in mood disorders: IV. Comparison of mania and depression

Cortical regional cerebral blood flow (rCBF) was assessed in minimally medicated, relatively young adults in episodes of either acute mania (n = 11) or major depression (n = 11) and in matched normal control subjects (n = 11), using the 133xenon inhalation method, under eyes-closed, resting conditions. The three groups were equivalent in global CBF. Both patient groups showed significant reductions of rCBF in anterior cortical areas and reduction of the normal anteroposterior gradient. In addition, there was evidence of abnormal, albeit similar, patterns of flow lateralization on a regional basis in both clinical groups compared with normal subjects. An exploratory analysis revealed preliminary evidence of rCBF differences between the clinical groups, localized to the inferior frontal cortex. Otherwise, the evidence in this study suggests that young adult manic and depressed patients are predominantly similar in cortical rCBF parameters.

Differential effects of mood on cortical cerebral blood flow: a 133xenon clearance study

Studies of healthy and clinical populations have suggested valence-specific cortical and subcortical neural systems regulating emotions. In a study of 12 normal volunteers, the 133xenon clearance method for measuring regional cerebral blood flow (CBF) was used to study the effects of experimentally controlled mood states on regional brain activity within superficial cortex. CBF was measured with 254 detectors and bolus infusion during a happy mood induction task, a sad mood induction task, a sex differentiation task, and a resting baseline condition. CBF increased during sad and decreased during happy mood induction, relative to the activated (sex differentiation) and the nonactivated (resting) nonemotional control conditions. Increased CBF during sad mood induction was correlated with greater negative mood changes. Conversely, increased CBF was associated with a stronger subjective experience of positive affect during happy mood induction. This suggests that cortical arousal may serve to intensify the conscious experience of emotion. Heart rate accelerated during happy and sad mood induction and during sex differentiation relative to a pretask baseline condition. Some regional specificity of effects was also observed. The occipital temporal region showed higher overall CBF during sad mood induction than during happy mood induction. The only region that showed specific lateralized changes in CBF which differentiated sad from happy states was the frontal pole, with left CBF being higher during sad and lower during happy mood induction relative to right CBF. For sad mood induction, there were significant regional differences among correlations between CBF and self-ratings. These were attributable to higher negative correlations (i.e., higher CBF correlates with negative self-rating) in midtemporal, occipital temporal, and postcentral regions. These correlations did not vary across the 15 regions for happy mood induction. For sad mood induction, heart rate correlated positively with CBF increase and with negative affect. Correlations were opposite for happy mood induction. The results suggest high cortical and autonomic arousal during negative/sad mood and low cortical and high autonomic arousal during positive/happy mood. They underscore the value of integrating emotional experience with physiologic measures in neuroimaging activation studies.

Standardized mood induction with happy and sad facial expressions

The feasibility of applying ecologically valid and socially relevant emotional stimuli in a standardized fashion to obtain reliable mood changes in healthy subjects was examined. The stimuli consisted of happy and sad facial expressions varying in intensity. Two mood-induction procedures (happy and sad, each consisting of 40 slides) were administered to 24 young healthy subjects, who were instructed to look at each slide (self-paced) and try to feel the happy or sad mood expressed by the person in the picture. On an emotional self-rating scale, subjects rated themselves as relatively happier during the happy mood-induction condition and as relatively sadder during the sad mood-induction condition. Conversely, they reported that they were less happy during the sad mood-induction condition and less sad during the happy mood-induction condition. The effects were generalized to positive and negative affect as measured by the Positive and Negative Affect Scale. The intraindividual variability in the effect was very small. In a retest study after 1 month, the mood-induction effects showed good stability over time. The results encourage the use of this mood-induction procedure as a neurobehavioral probe in physiologic neuroimaging studies for investigating the neural substrates of emotional experience.

The effect of anxiety induction on the regional uptake of 99mTc-exametazime in simple phobia as shown by single photon emission tomography (SPET)

Ten patients suffering from DSM-III-R simple phobia were studied under two conditions: (a) while listening to a 4 min relaxation tape, and (b) while listening to a 4 min audio tape describing exposure to the phobic stimulus. During each condition, subjects were injected with 99mTc-Exametazime, a marker of regional cerebral blood flow. Subjective and psychophysiological measures indicated a marked effect of the anxiety induction procedure. Ratio analysis of the SPET data revealed reductions in tracer uptake largely confined to posterior cerebral regions bilaterally. Analysis of brain regions of interest normalised to the whole brain slice showed reductions confined to right temporal/occipital regions. In general there was no clear association between subjective and physiological variables and changes in regional uptake of tracer as a consequence of the anxiety induction procedure. The changes in tracer uptake were dissimilar to those previously reported for other cognitive activation paradigms, providing some reassurance that those functional brain changes were not artefacts of non-specific changes in state anxiety. These posterior brain changes may reflect alterations in activation of the GABA/benzodiazepine complex.

Depersonalization after marijuana smoking

Depersonalization and other behavioral and physiological indices were monitored before and after the administration of high- and low-potency marijuana cigarettes and a placebo cigarette in 35 physically and mentally healthy normal volunteers. The cigarettes were administered under double-blind conditions during three visits to the laboratory separated by a minimum of 1 week. Marijuana smoking, but not placebo smoking, was associated with significant depersonalization that was maximal 30 min after smoking the high-potency cigarettes. Other behavioral changes induced by marijuana included disintegration of time sense, sensation of "high," increased state anxiety, tension, anger, and confusion. Respiration, pulse rate, and systolic blood pressure also increased after marijuana smoking. Multiple regression identified temporal disintegration as the most significant predictor of depersonalization.

Regional cerebral blood flow after marijuana smoking

Regional CBF was measured with the 133Xe inhalation technique before and thrice after smoking marijuana of two strengths and placebo in 20 physically and mentally healthy male volunteers with a previous history of exposure to marijuana. They were drug-free at the time of the study. Blood pressure, pulse rate, end-tidal carbon dioxide, end-tidal carbon monoxide, and forehead skin perfusion were quantified during the CBF measurements. Blood samples were drawn for quantification of plasma levels of delta 9-tetrahydrocannabinol (THC) before and during the 2 h after smoking marijuana or placebo. Drug-induced intoxication and changes in mood were quantified with rating scales. Marijuana smoking was associated with bilateral CBF increase, which was maximal 30 min later. Greater CBF increases were seen in the frontal region and right hemisphere. No significant CBF changes were seen after placebo. Pulse rate and respiration increased significantly after marijuana but not placebo. Both marijuana and placebo smoking were associated with increased end-tidal carbon monoxide. CBF increase in both hemispheres correlated significantly with degree of intoxication, plasma levels of THC, and pulse rate.

SPECT imaging in psychiatry. A review

In the last two decades, brain imaging has become an integral part of clinical and research psychiatry. Single photon computed emission tomography (SPECT) is rapidly gaining acceptance as one of the major imaging techniques available, along with computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET). Each of these techniques has its assets and drawbacks. This review concerns SPECT, a highly prevalent imaging technique whose potential value in brain imaging has not been appreciated until recently. Its purpose is to expose practicing clinicians and research psychiatrists alike to the attributes of this instrument, which is available in most nuclear medicine departments today. An effort is made to provide a comprehensive account of this technique, including a brief summary of the basic principles, the various methods of its application, and recent findings in most psychiatric disorders. Analogies to its "aristocratic cousin," PET, are presented to emphasize similarities and differences. Finally, directions for future development and implementation of SPECT are suggested.

Effect of the 5-HT1A partial agonist buspirone on regional cerebral blood flow in man

Repeated measurements of regional cerebral blood flow (rCBF) were made in normal volunteers before, and after, the administration of the 5-HT1A partial agonist, buspirone, or placebo. The difference in rCBF, before and after drug, (buspirone versus placebo) was used to identify brain areas affected by buspirone. Buspirone-induced changes in rCBF were studied under two behavioural conditions (5 word-list learning and 15 word-list learning). Compared to placebo, buspirone increased blood flow in the cuneus during both behavioural states. However, decreases in blood flow, centred in the left dorso-lateral prefrontal cortex and posterior cingulate cortex, were only observed under one of the two behavioural conditions. It is concluded that buspirone-induced alterations in regional cerebral blood flow are better understood, not in relation to the known distribution of monoamine neurotransmitter systems (particularly ascending 5-HT projections), but rather in relation to putative neuronal circuits possibly many synapses "downstream" of buspirone's pharmacological site of action.

Marchiafava-Bignami disease. A case studied by structural and functional brain imaging

Marchiafava-Bignami disease (MBD) is a rare complication of chronic alcoholism. The clinical features, X-ray, CT and MRI findings are well documented. However, functional brain imaging has not been used in cases of MBD. We used single-photon emission computed tomography (SPECT) to monitor the regional cerebral blood flow in a patient suffering from a acute form of MBD, from which he subsequently recovered. Several abnormalities were found. A more frequent use of functional brain imaging in MBD could improve our knowledge of pathogenesis and prognosis for MBD.

Evaluation of the effects of diazepam and an experimental anti-anxiety drug on regional cerebral blood flow

In the normal brain, cerebral blood flow (CBF) and function are closely coupled. Thus, changes in brain function associated with drug-induced anxiety reduction should be accompanied by parallel CBF changes. Benzodiazepines such as diazepam have been reported to reduce CBF. It is unclear, however, if this CBF decrease is specifically a function of the anti-anxiety property of the drug. To examine the relationship between drug-induced anxiety reduction and CBF changes more closely, i.v. injections of an established anxiolytic agent and an experimental anti-anxiety drug were given to patients with generalized anxiety disorder. CBF and anxiety levels were measured before and 30 min after i.v. administration of diazepam (0.12 mg/kg), ondansetron (0.24 mg/kg), and normal saline during separate visits to the laboratory. The order of drug administration was randomized, and the injections were given under double-blind conditions. Diazepam but not ondansetron or saline reduced anxiety. Global CBF reduction was seen after diazepam, but no changes were found following the other two experimental conditions. The CBF values were adjusted for test-retest changes in carbon dioxide levels. Postdiazepam decreases in CBF and anxiety levels did not correlate.

Relative protection from cerebral atherosclerosis of young patients with homozygous familial hypercholesterolemia

It is well known that hypercholesterolemia is correlated with coronary atherosclerosis, but no definite information is available on its association with cerebrovascular atherosclerosis. We studied 10 young patients (age 3-32 years) with homozygous familial hypercholesterolemia (FH), together with 3 normal relatives as healthy controls. Extra- and intracranial Doppler examination, MRI and cerebral blood flow by SPECT and 99mTc-HM-PAO were performed on all. Six out of 10 patients already had signs and symptoms of coronary heart disease, but all patients were free from ischemic brain lesions, as small as detectable at MRI, and had normal cerebral blood flow. Two patients presented significant stenosis of the carotid arteries at Doppler examination. Young patients with homozygous FH have early and clinically evident coronary atherosclerosis, while overt disease in the cerebral district is delayed despite the extremely elevated plasma cholesterol concentration. This was also confirmed by the autopsy of two patients, who died after the study and whose cerebral arteries were totally free from atherosclerotic lesions. The age, at which flow-reducing atherosclerotic lesions develop in hypercholesterolemic patients, differs with regard to the arterial district involved.

Mania: sympathoadrenal function and clinical state

We investigated sympathoadrenal and sympathetic nervous system activity, catecholamine disposition, and clinical state in 19 hospitalized manic patients. Severity of the core manic syndrome, anxiety, and hostility correlated with 24-hour urinary excretion of epinephrine relative to its metabolites, but only weakly with norepinephrine. Agitation, however, correlated most strongly and significantly with norepinephrine. Eight of the patients had mixed states: concurrent manic and depressive syndromes. There were no differences between mixed and pure manic patients with respect to catecholamine or metabolite excretion or precursor/product ratios, but mixed manic patients tended to have higher excretion of norepinephrine and had increased variance with respect to catecholamine measures. These data suggest that the function of the adrenal medulla, whether directly or indirectly, is important in the symptoms of both mixed and pure mania.