Genetic Explanations

• Genes can be used to explain OCD.

  • Genes are involved in vulnerability to OCD
  • OCD is polygenic
  • Genes cause different types of OCD
• Genes and vulnerability to OCD

  The diathesis-stress model suggests that there are certain genes that make people more vulnerable to the environmental factors that trigger OCD.
• In 1936, Lewis studied OCD patients and found that 37% of them have parents with OCD and 21% have siblings with OCD. This suggests that genes run in families, but it is genetic vulnerability not genetic certainty.
• Candidate genes are genes that create vulnerability to OCD. Some of these genes are involved in regulating serotonin, such as the 5HT1-D Beta
• Polygenic means that a condition is not caused by a single gene, but a combination of various genes that increase vulnerability.
• One group of genes may be present in two people, but only cause OCD in one of these people. This is known as etiologically heterogeneous, meaning that the origins of OCD can vary from one to another. Evidence suggests that different types of OCD may be a result of specific genetic variations, such as hoarding.
• In 2013, Taylor et al investigated whether OCD is polygenic by analysing previous studies and found that there could be 230 genes related to OCD. Some of these genes are neurotransmitters which have a role in regulating mood, such as dopamine and serotonin.