Religion and Spirituality in Psychiatry

54 Nader Perroudmost studied. These receptors are located bothpost- and presynaptically. Presynaptic 5-HT1Aautoreceptors are highly concentrated on cellbodies in the raphe and modulate the cell firingand release of several neurotransmitters in allbrain areas. Thus, the 5-HT1A receptor may havea role as general regulator of neurotransmitteractivity such as 5-HT and dopamine.In a recent positron emission tomography(PET) study, Borg et al.(20 ) found an associationbetween 5-HT1A receptor binding potentialand self-transcendence scores (a personalitytrait associated with spirituality, see previously)in healthy, male subjects. This association, however,depended completely on the subscalespiritual acceptance, which measures an individual’sapprehension of phenomena that cannot beexplained by objective demonstration. Whetherthe low 5-HT1A receptor density observed insubjects scoring high on a measure of spiritualityreflects low or high activity in 5-HT cortical projectionareas is not clear, and literature providessupport for both interpretations. Interestingly,several studies have found an abnormal densityof brain and platelet 5-HT2A and 5-HT1Areceptors in subjects suffering from some psychiatricdisorders. For example, it has been proposedthat 5-HT receptors may be up-regulatedin depressive disorder or in subjects displayingsuicidal behaviors as a compensatory responseto chronic low levels of 5-HT.(38 ) Followingthis hypothesis, low 5-HT1A receptor densityshould reflect higher 5-HT activity in the brainof subjects with high spirituality or at least ahigh efficiency of the 5-HT system. The resultscould be linked to the observed higher activityof 5-HT system during meditation and relatedexperiences. These findings could have importantimplications for the pathophysiology ofmany psychiatric disorders and the role of spiritualityin these conditions. However, it also hasto be stated that lower 5-HT1A receptor densityhas been linked to greater anxiety and chronicstress. The findings of Borg et al. are thereforealso consistent with the notion that those whoare more spiritual are biologically more prone toanxiety.(39 , 40 ) Understanding the complex linkbetween spirituality, the 5-HT system, environmentalfactors, and symptoms such as psychoticfeatures could help to find new ways to reducethe morbidity associated with several neuropsychiatricconditions. For example, activationof 5-HT1A receptors (by eltoprazine and other5-HT1A-receptor agonists) reduces aggressivebehavior.(41 ) Globally this observation adds tothe possible effect of religious practice on aggression.This should be taken into account in clinicalpractice.4.3. A Genetic PolymorphismA polymorphism is a genetic variant that appearsin at least 1 percent of a population, but in genetics,the term is reserved for variation in a population’sDNA. Genetic polymorphisms provide us with thepossibility to predict interindividual differencesin susceptibility to clinical disease. There are severaldifferent types of polymorphisms. The singlenucleotide polymorphism (SNP) refers to a variationof a single nucleotide (A, T, C, or G) within theDNA sequence between members of a species. Forexample, the following two DNA sequences fromdifferent individuals, AT T AGCC and AT CAGCC,differed by a single nucleotide, a C allele in place ofa T allele. The other polymorphism we shall consideris the insertion-deletion polymorphism. Aninsertion-deletion polymorphism is an insertion ordeletion of a part of the DNA that is found in somepeople but not in others. The sequence with theinsertion is normally called the long allele, whereasthe one with the deletion is called the short allele.Finally, short tandem repeat polymorphisms and/or variable numbers of tandem polymorphisms(VNTR) are short sequences of DNA that arerepeated numerous times in a gene.Polymorphisms may fall either within a codingregion or in a non-coding region. In the sameway they can change the amino acid sequenceof the protein. However, even if these polymorphismsare located in a non-coding region ordon’t change the amino acid sequence, they couldstill have great impact on the expression of theprotein. Given that, these variations in the DNAsequences can affect a number of diseases.