Platelet monoamine oxidase and serum dopamine-beta-hydroxylase activity in chronic alcoholics

Previous independent reports suggest that low platelet monoamine oxidase (MAO) activity and high serum dopamine-beta-hydroxylase (DBH) activity may be associated with alcoholism or vulnerability toward alcoholism. However, there are also contradictory reports in the literature with regard to each of these two enzymes. We measured both platelet MAO and serum DBH activity in alcoholics followed up at periodic intervals for 12 months after hospitalization for acute alcoholism. Platelet MAO activity in the alcoholics was significantly lower compared to that of nonpsychiatric controls throughout the 12-month period, whereas serum DBH activity in the alcoholics was essentially the same as control values. Thus, low platelet MAO activity, previously reported in a spectrum of clinical psychiatric disorders, appears to be a relatively stable phenomenon in chronic alcoholics irrespective of acute intoxication or pathophysiological factors associated with acute decompensation in individuals vulnerable to alcoholism.     

Platelet monoamine oxidase, plasma dopamine beta-hydroxylase activity, dementia and family history of alcoholism in chronic alcoholics

The authors measured platelet monoamine oxidase (MAO) activity and plasma dopamine beta-hydroxylase activity in 36 male chronic alcoholics during a period of non-abstinence, and in 29 normal controls. The influence of family history, dementia, chronicity of drinking and liver injury on the enzyme activities was also examined by multiple regression analysis. Platelet MAO was significantly lower in the alcoholic group. Both enzyme activities were negatively related to the presence of dementia, while low MAO activity was associated with positive family history (parents, sibs) of alcoholism.     

Effect of neuroleptic drugs on platelet monoamine oxidase in psychiatric patients

The authors determined the platelet MAO activity of 57 psychotic patients after a placebo period and after 3-65 days of neuroleptic treatment. Platelet MAO activity significantly decreased in both men and women after neuroleptic treatment. The platelet MAO activity of neuroleptic-treated schizophrenic women was significantly less than that of drug-free schizophrenic women, who did not differ from normal women. There were trends in the same direction for the schizophrenic men. Previous studies that reported lower platelet MAO activity in neuroleptic-treated schizophrenic patients than in normal controls may have been influenced by this neuroleptic effect.     

Familial biochemical and clinical correlates of alcoholics with low platelet monoamine oxidase activity.

This study substantiates previous reports that low platelet MAO activity is associated with alcoholism. The results also indicate that low platelet MAO activity in alcoholic probands is associated with a higher prevalence of psychiatric hospitalization in first-degree family members as well as alcoholism and suicide attempts among alcoholics. Psychiatrically ill family members of the alcoholic probands with low platelet MAO activity also demonstrate low enzyme activity whereas the well family members have normal enzyme activity.     

Platelet and fibroblast monoamine oxidase in alcoholism

Monoamine oxidase (MAO) activity has been reported to be low in platelets (MAO B) and brain (MAO A and B) of some patients with alcoholism compared to control subjects. Whether the decreased platelet MAO activity found in alcoholism is secondary to the effect of alcohol or exists before alcohol abuse is not clear. The hypothesis that altered MAO A activity is determined by an abnormality in the genetic regulation of the enzyme can be tested by measuring MAO A activity in human fibroblasts cultured under controlled conditions. We first studied the kinetic parameters of platelet MAO B activity in patients hospitalized for treatment of alcoholism. Vmax was 38% lower in the patients (n = 14) than in normal controls (n = 22), but the enzyme affinity (Km) for the substrate tyramine was unchanged. Patients with the five lowest levels of platelet MAO activity had MAO activity measured from fibroblasts cultured from skin punch biopsies. Their fibroblast MAO activity was within the normal range, showing a dissociation between platelet MAO B and fibroblast MAO A activities and suggesting that MAO A activity is not low for genetic reasons in alcoholic subjects who do have low platelet MAO B activity.     

Measurement of platelet monoamine oxidase using three different substrates in patients with alcoholism and schizophrenia

The platelet monoamine oxidase (MAO) activities in alcoholism and schizophrenia were investigated by means of simultaneous determination, using beta-phenyl-ethylamine, tryptamine and serotonin as substrates. No significant difference was found between the MAO levels in the alcoholic and schizophrenic groups, when tryptamine was used as a substrate, but both groups showed lower values than the controls. On the other hand, beta-phenylethylamine, a specific substrate for MAO B used as a substrate, showed no significant difference between the alcoholic and control groups in the activities. These two groups showed higher values in MAO activity than the schizophrenic group, whereas when MAO activity was estimated using serotonin, platelet enzyme was found to be inhibited significantly in alcoholism, and the level of activities in the schizophrenics was similar to that of the controls. Moreover, the beta-phenylethylamine inhibition curve obtained serotonin as the substrate in the pooled platelets of 50 normal human subjects, and the MAO activity could not be inhibited by higher concentrations than the Km value of serotonin. These findings suggested that there might be two interacting catabolic sites having different substrate affinities in blood platelet MAO. Thus, it could be speculated that serotonergic catabolic sites of MAO in the platelets are disturbed in the alcoholics, while beta-phenylethylaminergic catabolic sites of platelet MAO are inherently vulnerable in schizophrenia.     

Measurement of Platelet Monoamine Oxidase Using Three Different Substrates in Patients with Alcoholism and Schizophrenia

Abstract: The platelet monoamine oxidase (MAO) activities in alcoholism and schizophrenia were investigated by means of the simultaneous determination, using β-phenyl-ethylamine, tryptamine and serotonin as substrates. No significant difference was found between the MAO levels in the alcoholic and schizophrenic groups, when tryptamine was used as a substrate, but both groups showed lower values than the controls. On the other hand, β-phenylethylamine, a specific substrate for MAO B used as a substrate, showed no significant difference between the alcoholic and control groups in the activities. These two groups showed higher values in MAO activity than the schizophrenic group, whereas when MAO activity was estimated using serotonin, platelet enzyme was found to be inhibited significantly in alcoholism, and the level of activities in the schizophrenics was similar to that of the controls. Moreover, the β-phenylethylamine inhibition curve obtained serotonin as the substrate in the pooled platelets of 50 normal human subjects, and the MAO activity could not be inhibited by higher concentrations than the Km value of serotonin. These findings suggested that there might be two interacting catabolic sites having different substrate affinities in blood platelet MAO. Thus, it could be speculated that serotonergic catabolic sites of MAO in the platelets are disturbed in the alcoholics, while β-phenylethylaminergic catabolic sites of platelet MAO are inherently vulnerable in schizophrenia.     

Platelet MAO in subtypes of alcoholism

A number of investigators have observed low platelet monoamine oxidase (MAO) activity in alcoholism. There is also preliminary evidence suggesting that low enzyme activity is principally associated with one of two putative subtypes of alcohol dependence, i.e., type II (male limited). The results of this study are consistent with two previous reports of reduced platelet MAO activity in type II male alcoholics as compared with type I male alcoholics and normal, healthy male controls. Type I (milieu-limited) alcoholics showed a smaller reduction in enzyme activity. The observed differences do not appear to be related to concurrent use of other psychoactive substances, characteristic differences in age between type I alcoholics and type II alcoholics, antisocial personality disorder, or variation in platelet size. Low platelet MAO activity in alcoholics is possibly related to both state and trait factors and may be a useful biochemical measure to assist with subtyping.     

Platelet MAO activity in anorexia nervosa patients with and without a major depressive disorder

Platelet MAO activity was determined in 33 anorexia nervosa patients. A subgroup of 15 patients who met Research Diagnostic Criteria for a concomitant major depressive disorder were found to have, both initially and after 5 weeks of treatment, significantly lower mean platelet monoamine oxidase (MAO) activity than 28 matched normal control subjects. In contrast, mean platelet MAO activity in the patients who did not meet criteria for major depressive disorder was similar to values in control subjects. The authors found that significantly more depressed patients had low MAO activity compared with nondepressed patients and controls. Platelet MAO activity may be useful in discriminating among subtypes of anorexia nervosa patients.     

Platelet monoamine oxidase activity in elderly depressed outpatients

Platelet monoamine oxidase (MAO) activity was assayed in 42 unmedicated, elderly, RDC depressed, unipolar outpatients over 60 years of age, 17 nondepressed controls, and 17 younger volunteers without psychiatric illness. Elderly depressed women (n = 22) had significantly higher MAO activity than sex- and age-comparable controls. No significant relationships between MAO activity and duration of current depressive episode, duration of illness, or family history of affective disorder were obtained. These results extend to elderly female outpatients the finding that depression is associated with increased platelet MAO activity, exceeding the normal age-related increase.     

The alcoholic's self-image: a comparative study between men and women

Self-image is a central problem in alcoholism. Most theories about the relationships between the self-image of alcoholics and their behaviour have been derived from -clinical observations rather than empirical research. Most observations have pointed out that alcoholics are prone to underevaluation of themselves and that low self-image is the basis of much of the problem drinker's behaviour. All the research on self-image has concluded that alcoholics have a lower self-image than non-alcoholics. Some empirical research has been conducted on the self-image of alcoholics; it has, however, been carried out only a few times, restricted to small samples, and concerned with a limited number of aspects of self-image. Moreover, most of these studies are not recent, and it seems that this area of research is not well covered. Even though the hypothesis of a bad self-image in alcoholics was validated by various older studies, the representation of alcoholism has since changed. Because of this evolution, the ways in which the disease has been viewed have changed. One can question to what extent changes in society can influence the self-image of alcoholics. This question seems all the more pertinent for alcoholic women, given the evolution of the female condition since the Seventies. The objectives of this study are to evaluate the self-image of alcoholics and non-alcoholics, and to compare the self-image of male and female alcoholics. Our hypotheses are that: 1) the self-image of an alcoholic is more negative than that of a non-alcoholic, and that: 2) female alcoholics have a more negative self-image than male alcoholics. Two groups of 30 subjects each were made up: a group of alcoholics recruited in an alcohol-dependency unit and a group of non-alcoholics recruited in a public place. The comparison of socio-demographic data between the alcoholic group and the control group does not show a significant difference except for age and level of schooling. The average age of the control group is younger than that of the alcoholic group. The level of schooling of the control group is higher than that of the alcoholic group. These differences can be explained by the mode of recruitment of the participants. The significant differences between the alcoholic men and women are at the level of the number of Years of alcoholism, the age at which the disorder began and the number of detoxification episodes. These differences are probably due to cultural background. Indeed, the age at which alcoholism begins is later in women and they consult more quickly than men. The two groups were assessed using the Tennessee Self Concept Scale and the Self Esteem Inventory. Other tests were used to control factors capable of influencing self-image (depression, socio-demographic data). The results show that the alcoholics have a more negative self-image than the control group. The alcoholics perceived themselves significantly less favourably on the identity (what I am), self-satisfaction (how I feel about myself), and behaviour (what I do) scores than did those in the control group. The alcoholics also saw themselves in a significantly more negative light than did those in the control group on the scores relating to physical self (body, health.), moral-ethical self (moral worth), personal self (evaluation of personality), family self (adequacy and value as a family member) and social self (adequacy and worth in interaction with others). The self-criticism subscale provided further evidence that the alcoholics were more open and self-critical than were those in the control group. Female alcoholics had a lower self-image than male alcoholics, but not in every aspect. There was a significant difference between the scores of alcoholic women and alcoholic men, for three of the subscales measured by the Tennessee Self Concept Scale: "general self-image", "personal self" and "self-criticism". The alcoholic women perceived themselves more negatively when it came to "self-satisfaction", "personal self" and "social self". They were however more positive than the men in the sectors of "identity", "behaviour", "physical self", "moral-ethical self", and "family self". The alcoholic men were more openly self-critical than the alcoholic women. Our results confirm the conclusions of empirical studies and of clinical observations. Alcoholics see themselves as generally inadequate and unworthy of respect. The changes in representations of this disease seem to have influenced the alcoholic's self-image, but it remains however very negative. The alcoholics'negative self-image is generalised and not specific to personality and behaviour. The -representation of alcoholism seems to have contributed to an improvement in the self-esteem and self-image of alcoholics, and in particular of female alcoholics. Even if the self-image of alcoholic women remains more negative than that of alcoholic men, it tends to bring back the self-image of alcoholic women to a level close to that of the men.     

Platelet monoamine oxidase activity in obsessive-compulsive disorder

Response to SSRIs suggests the implication of the serotonergic system in obsessive-compulsive disorder (OCD). However, biological studies on serotonergic function in OCD have yielded contradictory results. Platelet monoamine oxidase (MAO) activity has been proposed as an index of cerebral serotonin activity. The aim of this study was to examine platelet MAO activity in 29 OCD patients and 29 healthy controls matched by age, sex and tobacco use. We also explored the relationship between platelet MAO activity and aggressive obsessions in OCD patients. There were no differences in platelet MAO activity between OCD patients and healthy controls. We found a significant correlation between platelet MAO activity and Y-BOCS scores in the group of patients with Y-BOCS scores >15. OCD patients with aggressive obsessions had significantly lower levels of platelet MAO activity than patients without aggressive obsessions. Our results suggest that platelet MAO activity may be a marker of OCD severity, and that low platelet MAO activity may be associated with aggressive obsessions in OCD patients.     

Platelet monoamine oxidase: low activity in cigarette smokers

Platelet monoamine oxidase (MAO) activity and plasma thiocyanate concentration (an index of smoking behavior) were measured in 109 normal male and female volunteers. MAO activity was significantly lower and plasma thiocyanate concentration significantly higher in smoking volunteers than in nonsmoking volunteers. A significant negative correlation between MAO activity and thiocyanate concentration was observed in female smokers (rs = 0.43, n = 36) but not for male smokers (rs = 0.02, n = 31). In nine smokers who gave up smoking, mean (+/- SD) platelet MAO activity increased significantly (17.5 +/- 4.1 nmole/mg/hour to 24.6 +/- 4.2 nmole/mg/hour). At the same time, mean (+/- SD) plasma thiocyanate concentrations decreased significantly (144 +/- 41 microM to 50 +/- 12 microM). These data suggest that smoking directly or indirectly reduced platelet MAO activity.     

Platelet monoamine oxidase and clinical phenomenology of schizophrenia

Platelet monoamine oxidase activity (MAO) was determined in 39 unmedicated chronic schizophrenic patients and 88 normal control subjects. Platelet MAO activity did not distinguish paranoid from nonparanoid patients or patients who met Taylor and Abrams criteria for narrowly defined schizophrenia from other schizophrenics. Enzyme activity was not related to either prognostic scores or age at onset of illness. MAO activity was decreased in patients compared to controls, and was lower in males than in females. Our findings indicate that clinical phenomenology, as defined in the present study, is of limited use in identifying biological subtypes of schizophrenia with deviant platelet MAO activity.     

Vitamin B12-induced reduction of platelet monoamine oxidase activity in patients with dementia and pernicious anaemia

Platelet monoamine oxidase (MAO) activity has previously been shown to be increased in patients with senile dementia of Alzheimer type (SDAT) and in patients with megaloblastic anaemia. Moreover, low serum B12 levels were found to be 4-5 times more frequent in SDAT compared with an unselected population of similar age. In the present investigation, platelet MAO activity was estimated in 14 SDAT patients with relatively low serum B12 levels and in 4 patients with pernicious anaemia. Before B12 therapy, platelet MAO activity was significantly increased in both patient groups compared with a control group. After B12 therapy, platelet MAO activity was significantly reduced in both patient groups to apparently normal levels. The present results show that B12 status is a controlling factor of platelet MAO activity and confirm that a significant connection exists between vitamin B12 deficiency and primary degenerative dementia disorders, such as SDAT.     

Platelet MAO activity as a biological marker in subgroups of alcoholism

In the Stockholm Adoption Study, two types of alcoholism, "Type I" and "Type II", have been identified on the basis of genetic predisposition. In the present study, this classification has been applied to a clinical sample. The two types of alcoholism were clinically clearly identifiable. Type I alcoholism was characterized by late onset and few social complications. Type II alcoholism was characterized by early onset, use and abuse not only of alcohol, but also of glue, cannabis, amphetamine and opioids, together with several social complications. The subjects with Type II alcoholism had also more alcoholism and depression among their first-degree relatives than the subjects with Type I alcoholism. Furthermore, the two types of alcoholism were separable by means of the biological marker - platelet MAO activity. While platelet MAO activity was normal in Type I alcoholics, as compared with healthy controls, it was clearly low in the Type II alcoholics. This subclassification of alcoholism seems to be of value in future studies concerning the etiology, epidemiology and treatment of alcoholism.     

Criminality and platelet monoamine oxidase activity in former juvenile delinquents as adults

Platelet monoamine oxidase (MAO) activity was estimated in 70 former delinquent boys and 40 controls now aged 38–46 years. Platelet MAO activity was compared with their early criminal behaviour (before the age of 15) and their late registered criminality from the age of 15). Mean platelet MAO activity in subjects with both early and late criminality was significantly lower than that in former delinquents without late criminality. There was no significant difference in mean platelet MAO activity between controls and delinquents with early but no late criminality. When delinquents with early criminality were divided into a low and a high MAO group, the relative risk to be registered for late criminality was about 3.1 times higher for the subjects in the low MAO group. Thus, individuals with low platelet MAO activity run an increased risk of continued criminal behaviour.     

Platelet monoamine oxidase and sex hormones in a population of depressed patients

The association between changes in platelet MAO activity and Major Depressive Episode have been demonstrated. Cyclical changes in sex hormones serum levels had never been related with changes of MAO activity in depressed patients. Platelet MAO activity, oestrogen serum levels, progesterone serum levels and testosterone serum levels, have been measured in drug free depressed patients: 22 men and 42 women. This study demonstrates no relationship between serum levels hormons and platelet MAO activity, measured in men and in women. If young women are separated from menopaused women, platelet MAO activity is negatively correlated with oestrogen serum levels, in non menopaused women. Significance of this variation in studies about the use of MAO as a biochemical marker in depression is discussed.     

Psychobiology of borderline personality traits related to subtypes of eating disorders: a study of platelet MAO activity

Increased and decreased levers of platelet monoamine oxidase (MAO) activity have been reported in patients with eating disorders, indicating abnormalities of the serotonin turnover. However, whether these findings are related to eating disorders or are rather reflecting the pathophysiology of borderline personality traits in these patients is still unknown. Platelet MAO activity and comorbid personality disorders were investigated in 72 patients with different subtypes of eating disorders (ED) and in a group of 28 healthy controls. ED patients comprised the following subtypes: 25 anorexia nervosa (AN) restrictive, 14 AN binge eating-purging (AN b-p), 3 anorexia nervosa not otherwise specified (AN NOS) and 30 bulimia nervosa (BN). Personality disorders and traits were assessed with the Structured Interview for Personality Disorders (SCID-II), the Zanarini Rating Scale for Borderline Personality Disorder, and the Barrat Impulsiveness Scale. Platelet MAO activity was significantly lower in ED patients with comorbid borderline personality disorder (BPD) than in ED without Borderline personality disorder (BDP). Platelet MAO activity was significantly and inversely correlated with the number and severity of BPD clinical features. In the subsample of patients with binge eating-purging symptoms (AN b-p, AN NOS and BN), platelet MAO activity was significantly lower in binge-purge patients with comorbid BPD than in binge-purge patients without BPD. The whole group of eating disorders had a significantly reduced lever of platelet MAO activity compared with the control group. The results suggest that low platelet MAO activity might characterize eating disorders with comorbid borderline personality traits, reflecting greater serotonin dysfunction in these patients. The role of decreased platelet MAO as an endophenotype with specific clinical manifestations should be explored in future studies.     

Platelet monoamine oxidase and plasma dopamine-beta-hydroxylase activities in patients with multiple sclerosis

Platelet monoamine oxidase (MAO) and plasma dopamine-beta-hydroxylase (DBH) activities were determined in a large group of multiple sclerose patients in relapse (49 patients) and in remission (28 patients), and compared with an age- and sex-matched control group (52 normal subjects). The activities of both enzymes did not differ from normal in both patient groups. Women had higher MAO activities both in normal and in patient groups. Multiple linear regression analysis revealed an association of low platelet MAO to the score in the mental subscale in the Kurtzke Disability Status Scale. Both male and female patients with mental symptomatology had significantly (p = 0.02) lower platelet MAO activities compared to the patients without. The possibility of a relationship between MAO activity and psychiatric vulnerability in MS is considered.