Personality profile in type I alcoholism: long duration of alcohol intake and low serotonergic activity are predictive factors of anxiety proneness

The association between HTR1B gene rs13212041 polymorphism and onset of alcohol abuse

BACKGROUND

Alcohol dependence displays a wide variety of clinical phenotypes. Various typology classifications of alcoholism include age of onset of alcohol abuse as one of the major phenotypic features. Serotonergic changes have been associated with alcoholism, while serotonin receptors type 1B (5-HT1B) play an important role in regulating serotonergic neurotransmission. The rs13212041 polymorphism modulates the expression of HTR1B gene coding for 5-HT1B receptor. This study examined the association of platelet serotonin (5-HT) and HTR1B gene with the onset of alcohol abuse in alcohol-dependent subjects.

MATERIALS AND METHODS

Determination of platelet 5-HT concentration and genotyping of rs13212041 HTR1B gene polymorphism were performed in 613 alcohol-dependent patients, subdivided according to early/late onset (before/after 25 years of age) of alcohol abuse.

RESULTS

Alcohol-dependent individuals with CC genotype were more frequent in the group with early onset of alcohol abuse compared to carriers of T allele. Besides HTR1B genotype, age and gender, but not platelet 5-HT, were major variables associated with the onset of alcohol abuse. Platelet 5-HT concentration was not significantly different between patients with early and late onset of alcohol abuse, or patients carrying various HTR1B genotypes. Although we observed no influence of co-variables such as age, gender, or somatic and psychiatric comorbidities, platelet 5-HT concentration was significantly affected by smoking.

CONCLUSION

These findings support potential involvement of 5-HT1B receptors in the onset of alcohol abuse and development of alcohol dependence. Additionally, the results of our study emphasize the importance of controlling for smoking status, as one of the significant confounding factors influencing platelet 5-HT concentration.

Variation of types of alcoholism: review and subtypes identified in Han Chinese

Alcoholism, as it has been hypothesized, is caused by a highly heterogeneous genetic load. Since 1960, many reports have used the bio-psycho-social approach to subtype alcoholism; however, no subtypes have been genetically validated. We reviewed and compared the major single-gene, multiple-gene, and gene-to-gene interaction studies on alcoholism published during the past quarter-century, including many recent studies that have made contributions to the subtyping of alcoholism. Four subtypes of alcoholism have been reported: [1] pure alcoholism, [2] anxiety/depression alcoholism, [3] antisocial alcoholism, and [4] mixed alcoholism. Most of the important studies focused on three genes: DRD2, MAOA, and ALDH2. Therefore, our review focuses on these three genes.

Overexpression of 5-HT(1B) mRNA in nucleus accumbens shell projection neurons differentially affects microarchitecture of initiation and maintenance of ethanol consumption

Serotonin 1B (5-HT(1B)) heteroreceptors on nucleus accumbens shell (NAcSh) projection neurons have been shown to enhance the voluntary consumption of alcohol by rats, presumably by modulating the activity of the mesolimbic reward pathway. The present study examined whether increasing 5-HT(1B) receptors expressed on NAcSh projection neurons by means of virus-mediated gene transfer enhances ethanol consumption during the initiation or maintenance phase of drinking and alters the temporal pattern of drinking behavior. Animals received stereotaxic injections of viral vectors expressing either 5-HT(1B) receptor and green fluorescent protein (GFP) or GFP alone. Home cages equipped with a three-bottle (water and 6 and 12% ethanol) lickometer system recorded animals' drinking behaviors continuously, capturing either initiation or maintenance of drinking behavior patterns. Overexpression of 5-HT(1B) receptors during initiation increased consumption of 12% ethanol during both forced-access and free-choice consumption. There was a shift in drinking pattern for 6% ethanol with an increase in number of drinking bouts per day, although the total number of drinking bouts for 12% ethanol was not different. Finally, increased 5-HT(1B) expression induced more bouts with very high-frequency licking from the ethanol bottle sippers. During the maintenance phase of drinking, there were no differences between groups in total volume of ethanol consumed; however, there was a shift toward drinking bouts of longer duration, especially for 12% ethanol. This suggests that during maintenance drinking, increased 5-HT(1B) receptors facilitate longer drinking bouts of more modest volumes. Taken together, these results indicate that 5-HT(1B) receptors expressed on NAcSh projection neurons facilitate ethanol drinking, with different effects during initiation and maintenance of ethanol-drinking behavior.

Relationship of alexithymia and temperament and character dimensions with lifetime post-traumatic stress disorder in male alcohol-dependent inpatients

AIMS

The purpose of the present study was to evaluate the prevalence of lifetime post-traumatic stress disorder (PTSD) in male alcohol-dependent inpatients and to investigate the relationship of PTSD with alexithymia and temperament and character dimensions.

METHODS

Participants were 156 consecutively admitted male alcohol-dependent subjects. Patients were investigated using the Clinician-Administered PTSD Scale (CAPS), the Toronto Alexithymia Scale (TAS-20) and the Temperament and Character Inventory (TCI).

RESULTS

Among alcohol-dependent inpatients 32.1% were considered as having lifetime PTSD. Mean scores of alexithymia, novelty seeking (NS), harm avoidance (HA) and self-transcendence (ST) were higher in the PTSD group, whereas age and self-directedness (S) were lower. Among age and other factors of TAS-20, 'difficulty in identifying feelings (DIF)' predicted PTSD in a logistic regression model. When age and personality dimensions of TCI were taken as independent variables, S predicted PTSD in the logistic regression model. Finally, among subscales of TCI, 'impulsiveness versus reflection' (NS2) and 'congruent second nature versus bad habits' (S5) predicted PTSD.

CONCLUSIONS

Alexithymia and personality traits, particularly high DIF and S scores are related with lifetime PTSD diagnosis, even when controlling for age among alcohol-dependent inpatients. Causal relationships between alexithymia, personality dimensions and PTSD, and their implications on treatment are not clear and should be evaluated in longitudinal studies.

Alexithymia and personality dimensions in relation to depression and anxiety in male alcohol-dependent inpatients

Objective. The aim of this study was to determine the relationship of alexithymia and temperament and character model of personality with depression and anxiety symptoms in detoxified male alcohol-dependent inpatients. Method. The subjects consisted of 176 male alcohol-dependent inpatients according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition. Patients were investigated with the Beck Depression Inventory, Beck Anxiety Inventory, State and Trait Anxiety Inventory, Michigan Alcoholism Screening Test (MAST), Toronto Alexithymia Scale (TAS-20) and Temperament and Character Inventory (TCI). Results. MAST score and scores of all three factors of the TAS-20 significantly predicted depression scale and anxiety scales. Difficulty in identifying feelings and difficulty in describing feelings factors were particularly effective, relative to the externally orientated thinking factor of the TAS-20 for prediction depression and anxiety. The TCI dimensions emerged as distinct and conceptually meaningful predictors for the depression scale and anxiety scales. Conclusion. Depression and anxiety symptoms among detoxified male alcohol dependents are associated with alexithymia, a broad range of personality dimensions and higher severity of alcohol-related problems, which make these related factors highly relevant for clinical practice.

Modulation of high alcohol drinking in the inbred Fawn-Hooded (FH/Wjd) rat strain: implications for treatment

The Fawn-Hooded rat (FH/Wjd) is an inbred alcohol-preferring rat strain, unlike most of the other strains that were selectively bred for high alcohol intake and preference. It was chosen for study some 16 years ago because of a reported mutation that disrupted platelet serotonin function. Although the FH/Wjd rat has high alcohol intake (>5 g/kg/day) and preference (>65%), interbreeding with an alcohol-non-preferring inbred strain suggested that these measures are unrelated to the serotonin abnormality. Similarly, the exaggerated immobility of the FH/Wjd rats in the forced swim test did not correlate with the high alcohol intake. Many compounds have been tested in the FH/Wjd rats after both acute and chronic treatment and a substantial number of them have proved effective. However, as the case with opiate antagonists, tolerance to the effects of the drug can develop. An up-regulation of opioid receptors accompanied the chronic treatment and this mechanism may account for the development of tolerance. Tolerance to opiate antagonists has also been demonstrated in two of the selectively bred alcohol-preferring rat lines, but it is unknown whether this process may contribute to the relapses seen in individuals being treated with naltrexone. Other drugs that reliably decrease alcohol intake in the FH/Wjd rats include the 5-hydroxytryptamine-2A receptor antagonist, amperozide, the mGlu5 receptor antagonist 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]pyridine (MTEP) and herbal derivatives such as ibogaine, St. John's wort and kudzu extract. Thus, studies in the FH/Wjd rat have led to the discovery of a wide variety of targets for the development of novel agents to treat alcoholism. The fact that several of these drugs were shown to reduce alcohol intake in some of the selectively bred alcohol-preferring rat lines and/or alcohol-preferring vervet monkeys increases our confidence that they are good candidates for further development.