BIOLOGICAL APPROACH EXPLAINING OCD

ONE GROUP GENES CAUSE OCD ONE PERSON BUT DIFFERENT GROUP IN ANOTHER

AETIOLOGICALLY HETEROGENEOUS MEANING ORIGIN HAS DIFFERENT CAUSES

EVIDENCE REUSLT GENETIC VARIATIONS SUCH AS HOARDING DISORDER & RELIGIOUS OBSESSIONS

OCD POLYGENIC

NOT CAUSED SINGLE GENE - BUT SEVERAL

TAYLOR ANALYSED FINDINGS PREVIOUS STUDIES EVIDENCE 230 GENES MAY BE INVOLVED

GENES STUDIES - ASSOCIATED DOPAMINE & SEROTONIN - NEUROTRANSMITTERS - ROLE REGULATING MOOD

NEURAL MECHANISMS E.G. ANTIDEPRESSANTS WORK PURELY SEROTONIN SYSTEM INCREASING LEVELS NEUROTRANSMITERS

DRUGS EFFECTIVE REDUCING SYMPTOMS - SUGGEST SEROTONIN INVOLVED

SYMPTOMS FORM PART NUMBER CONDITIONS - BIOLOGICAL ORIGIN E.G. PARKINSONS (NETSADT)

SUGGEST BIOLOGICAL PROCESS CAUSE SYMPTOMS CONDITIONS RESPONSIBLE OCD

STUDIES DECISION MAKING SHOWN NEURAL SYSTEMS SAME SYSTEMS FUNCTION ABNORMALLY OCD - CAVEDINI

RESEARCHER IDENTIFIED BRAIN SYSTSEMS INVOLVED SOMETIMES - NO SYSTEM BEEN FOUND ALWAYS PLAYS PART

TEHREORE CANT CLAIM UNDERSTAND NERUAL MECHANISMS

EVIDENCE SUGGEST VARIOUS NEUROTRANSMITTERS DONT FUNCTION NOMRALLY IN PATIENTS

NOT SAME SAYING ABNORMAL FUNCTIONING CAUSES OCD

BIOLOGICAL ABNOMALITIES RESULT OCD RATHER CAUSE

GENES INVOLVED VULNERABILITY

LEWIS OBSERVED 37% PATIENTS HAD PARENTS WITH OCD AND 21% AND SIBLINGS WITH OCD

SUGGESTS VULNERABILITY PASSED ON THROUGH FAMILIES

DAITHESIS-STRESS MODEL CERTAIN GENES LEACE PEOPLE MORE LIKELY SUFFER MENTAL DISORDER 

SOME ENVIORNMENTAL STRESS TRIGGER

IDENTIFIED CANDIDATE GENES CREATE VULNERABILITY

INVOLVED REGULATING DEVELOPMENT SEROTONIN SYSTEM

GENE 5HT1-D BETA IMPLICATED EFFICENCY TRANSPORT SEROTONIN ACCROSS SYNAPSES

TWIN STUDIES STRONGLY SUGGEST OCD GENETIC CONTROL

PSYCHOLOGISTS LESS SUCCESSFUL PINNING DOWN GENES INVOLVED

SEVERAL GENES INVOLVED - GENETIC VARIATION INCREASES RISK OCD BY FRACTION

UNLIKELY USEFUL PROVIDES LITTLE PREDICTIVE VALUE

TRIGGER / INCREASE RISK DEVELOPING OCD

CROMER ET AL FOUND OVER HALF PATIENTS HAD TRAUMATIC EVENT PAST

OCD MORE SEVERE MULTIPLE TRAUMAS

OCD CANT BE ENTIRELY GENETIC ORIGIN - MORE PRODUCTIVE FOCUS ENVIORNMENTAL CAUSES - MORE ABLE TO DO SOMETHING ABOUT THESE

SOME CASES ASSOCIATED IMPARIED DECISION MAKING

ASSOCIATED ABNORMAL FUNCTIONING LATERAL OF FRONTAL LOBES OF BRAIN

FRONTAL LOBES FRONT PART OF BRAIN RESPONSIBLE LOGICAL THINKING

EVIDENCE SUGGEST PARAHIPPOCAMPAL GYRUS ASSOCIATED PROCESSING UNPLEASENT EMOTIONS FUNCTIONS ABNORMALLY OCD

NEURTOTRANSMITTERS RESPONSIBLE RELAYING INFO ONE NEURON TO ANOTHER

LOW LEVELS SEROTONIN NORMAL TRANSMISSION MOOD-RELEVANT INFO DOESNT TAKE PLACE

SOME CASES OCD EXPLAINED REDUCTION FUNCTIONING SEROTONIN SYSTEM IN BRAIN

EVIDENCE VARIETY SOURCES PEOPLE VULNERABLE DUE GENETIC MAKE UP

TWIN STUDIES

NESTADT ET AL REVIEWD PREVIOUS STUDIES 68% IDENTICAL TWINS SHARED OCD OPPOSED 31% NON-IDENTICAL 

STRONGLY SUGGEST GENETIC INFLUENCE