<prompt> Increased suicidal tendency is associated with:Increased noradrenalineDecreased serotoninDecreased dopamineIncreased GABA  <response>: Decreased levels of 5 HIAA which is a metabolite of serotonin are related to increased risk of suicide. 5-HIAA 5-hydroxyindoleacetic acid MHPG 3-methoxy-4-hydroxyphenylglycol Increased risk of suicide. HVA homovanillic acid Schizophrenia and other conditions involvingpsychosis HVA Parkinsons diseaseTreatment with antipsychotic agentsDepression Two alleles, U and L are involved in the gene polymorphism for the enzyme tryptophan hydroxylase involved in serotonin synthesis. Of the two alleles,presence of L allele increases suicidal riskmore than U allele. For example, multiple suicide attempts was found most often in subjects with the LL genotype and to a lesser extent among those with the UL genotype. 