<prompt> Biological marker for antisocial behaviour in boys:Low serum testosteroneLow resting pulse rateIncreased urinary dopamine levelsShortened REM latency  <response>: Ans: b Low resting pulse rateRef. 1.Valencia M, Arias JMC, Potential Biomarkers in Personality Disorders: Current State and Future Research, International Journal of Psychological Research 2016; 91: 98-1122. Sjoberg, R.L., et at. A Non-additive Interaction of a Functional MAO-A VNTR and Testosterone Predicts Antisocial Behavior, Neuropsychopharmacology 2007; 33: 425-4303. Todd A, et al. Low Resting Heart Rate and Antisocial Behavior: A Brief Review of Evidence and Preliminary Results from a New Test, Criminal Justice and Behavior 2009; 3611: 1125-11404. Herbert C. Quay, Anne E. Hogan, Handbook of Disruptive Behavior Disorders, 1st edition, 1999A biological marker or simply biomarker is a measurable indicator of any biological state or condition. Biomarkers are useful to examine normal biological processes, pathological processes, or responses to any intervention.Human behavior is due to neuro-humoral mechanism Neurological and Endocrine. Hence, chemicals neurotransmitters, hormones, neurological responses, anatomical changes of brain can be used as biomarkers of behavior.Antisocial BehaviorAntisocial behavior is any behavior which is harmful to others. This may range from lying to killing. The harm may be directed towards an individual or group of individuals or an institution or property. A person or a group of people gang can indulge in anti-social behavior.It is seen in following disorders:Its characteristic of antisocial personality disorder ASPDDisruptive behavior disorders ADHD, Oppositional defiant disorder, Conduct disorder. Note, some of them may go on to develop ASPD in futureHarm to others can occur in delirium altered consciousness; dementia memory impairment; substance intoxication withdrawal; maniahypomania irritable moodBiomarkers of antisocial behavior are divided into:Positive correlation: Testosterone well proven markerNegative correlation: Pulse rate restingUnclear: Dopamine and Serotonin and their metabolites levelCurrently, hyperdopaminergia and hyposerotonin in brain are implicated with higher level of aggression and antisocial behavior. This is reflected in level of metabolites in CSFurine of these neurotransmitters High HVA - for Dopamine; Low 5-HIAA-for SerotoninFrom a common sense point of view, antisocial behavior people have nolow empathysympathy; hence they sleep well even after crime no shortening of REM latency dont feel anxiousremorse no sympathetic stimulation while doing crimepost crime - low pulse rate. 