ocd

• ocd is defined by obsessions which are constant intrusive thoughts that cause high anxiety levels
• compulsion that are the behavioural response an attempt to deal with the continuous invasive thought processes
• compulsions are repetitive
• compulsions reduce anxiety
• the three behavioural charachteristics of ocd are:

  • avoidance
  • social impairment
  • compulsions
• the two emotional characteristics of ocd are:

  • anxiety
  • depression
• the three cognitive characteristics of ocd are:

  • obsessions
  • hyper vigilance
  • selective attention
• avoidance - take or resist actions to avoid being in the presence of objects/situations that trigger obsessions
• social impairment - not participating in enjoyable social activities. this social withdrawal is often due to difficulty leaving the hose without triggering obsessions or the need to carry out compulsion becomes time consuming
• compulsions - behaviours performed repeatedly yo reduce anxiety; however any anxiety reduction is only temporary e.g. checking behaviours
• anxiety - an uncomfortably high and persistent state of arousal, making it difficult to relax
• depression - a constant and long-lasting sense of sadness, the result of being unable to control the anxiety-causing thoughts and the OCD symptoms
• obsessions - intrusive, irrational and recurrent thoughts that tend to be unpleasant catastrophic thoughts about potential dangers
• hyper-vigilance - a permanent state of alertness where the sufferer is looking for the source of their obsessive thoughts
• selective attention - this means the individual with OCD is so focused on the object’s connected to the obsession they cannot focus on other things in their environment or concentrate on conversations
• there is no ocd gene, however its thought a vulnerability or predisposition to ocd is inherited from parents
• genetic analysis has revealed around 230 seperatre candidate genes found more frequently in people with ocd, many candidate genes influence the functioning of neutral systems in the brain; e.g. the SERT gene affects the reputake in the serotonin system
• evidence for the heritability of OCD comes from family and twin studies. however with OCD, the more closely genetically related to two people are, the higher the concordance: first-degree relatives have 10% concordance, and non-identical/dizygotic twins have 31% concordance
• neural explanations for OCD: include biochemical causes, an imbalance of neurotransmitters and the large neutral structures in the brain that are made of many neurons
• low serotonin levels are thought to cause obsessive thoughts, and the low level of serotonin is likely due to it being removed too quickly from the synapse before it has been able to transmit its signal/influence the postsynaptic cell
• serotonin and other neurotransmitters are other chemical messengers; presynaptic neurons release neurotransmitters, and receptors on the postsynaptic neuron detect these; if the signal is strong enough
• then the message is passed on the neurotransmitters detach from the receptors and are taken back to the presynaptic neuron through a process called reuptake
• it seems this process happens too quickly in people with ocd, leading to reduced serotonin levels in the synapse
• the SERT gene is the gene responsible for serotonin transportation in the synapse
• the ‘worry circuit’ - a set of brain structures including the OFC, the basal ganglia system, especially the caudate nucleus and the thalamus
• communication between these structures in the worry circuit appears to be overactive in people with ocd
• in normal functioning, the basal ganglia filter out minor worries, coming from the OFC, but if this area is hyperactive, even small worries get to the thalamus, which is then passed back to the OFC forming a loop
• repetitive motor functions are an attempt to break this loop. while carrying out the compulsion may give temporary relief, the hyperactive based ganglia will soon resume the worry circuit