Abstract

JIMENEZ-ARRIERO, M.A. et al. TaqI-A polymorphism linked to the DRD2 gene and P300 in alcoholic patients. Eur. J. Psychiat. [online]. 2006, vol.20, n.1, pp.45-53. ISSN 0213-6163.

BACKGROUND AND OBJECTIVES: Different studies carried out mainly in young non-consuming children of alcoholics show an association of P300 abnormalities with alcoholism and with the TaqI-A1 allele. Since the relationship between P300 and the TaqI-A1 allele has not been specifically studied in alcoholic patients, our objective was to investigate whether the association exits in this population. METHODS: Our sample consisted of 176 recently detoxified male alcohol-dependent patients. These patients had been alcohol dependent from a mean age of 22.6 years and consumed on average 164.63 (± 142.99) cm³ of alcohol daily. P300 was studied using an auditory paradigm. TaqI-A polymorphism genotyping was performed. The association between P300 and TaqI-A, and correlation with age and alcohol consumption, was studied. RESULTS: The TaqI-A1 allele was found in 38.6% of our patients (n = 68). The latency and amplitude of P300 were 361.64 milliseconds and 17.53 microvolts, respectively. P300 wave latency in alcoholic patients was longer than the reference value obtained from a sample of healthy men of the Event-Related Potentials Unit (p < 0.001). Alcoholic patients who carried the TaqI-A1 allele showed more prolonged P300 latency than non-carriers, and these in turn more than the control subjects. P300 characteristics varied according to age, but an association with amount of alcohol or number of years consuming was not found. CONCLUSIONS: There is a relationship between the TaqI-A polymorphism and P300 wave characteristics in alcoholic patients. Further investigations need to be carried out in non-consuming alcoholic patients and in healthy control subjects to confirm this association and to clarify the possible influence of the neurotoxic effects of alcohol on P300 physiology.

Keywords : P300; TaqI-A1; Alcoholism; Evoked Potentials; Addiction; Endophenotype.

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