biological approach to explaining OCD: neural explanations

Question 1

what are neural explanations?

Answer 1

the view that physical and psychological characteristics are determined by the behaviour of the nervous system, particularly in the brain as well as the nervous system

Question 2

how can OCD be explained because of the role of the neurotransmitter serotonin?

Answer 2

• serotonin is believed to help regulate mood
• neurotransmitters are responsible for relaying information from one neuron to another
• if a person has low levels of serotonin then normal transmission of mood-relevant information does not take place and a person may experience low moods
• a reduction in serotonin can explain some cases of OCD

Question 3

what is the SERT gene?

Answer 3

• the serotonin transporter gene, which codes for a protein called the serotonin transporter (SERT)
• this protein is responsible for regulating the levels of serotonin
• variations in the SERT gene can impact the functioning of the serotonin transporter protein, leading to differences in serotonin reuptake and availability in the synaptic cleft

Question 4

what is the role of the parahippocampal gyrus in OCD?

Answer 4

• it is interconnected with other brain regions implicated in OCD eg. orbitofrontal cortex (decision-making) and basal ganglia (motor control)
• disregulation in the connections between these regions may underlie the obsessive thoughts and compulsive behaviours seen in OCD
• abnormal functioning of the parahippocampal gyrus is related to regulation of unpleasant emotions

Question 5

how can the the orbitofrontal cortex (OFC) and the thalamus explain OCD?

Answer 5

• the OFC is involved in decision making and worry about social and other behaviour
• in OCD, the OFC and the thalamus are believed to be overactive

Question 6

what would an overactive thalamus or OFC result in?

Answer 6

• overactive thalamus: increased motivation to clean or check for safety
• if the thalamus was overactive, the OFC would become overactive as a result
• overactive OFC: increased anxiety and increased planning to avoid anxiety

Question 7

what is the basal ganglia involved in?

Answer 7

• area of the brain responsible for innate psychomotor functions
• its main job is to control how we move, from starting a movement to stopping it, and everything in between

Question 8

what did rapport and wise propose about the basal ganglia’s connection to OCD?

Answer 8

the hypersensitivity of the basal ganglia gives rise to the repetitive motor behaviours seen in OCD eg. repetitive washing / cleaning / checking

Question 9

how is OCD associated with impaired decision-making?

Answer 9

• associated with abnormal functioning of the lateral frontal lobes of the brain
• the frontal lobes are the front part of the brain that are responsible for logical thinking and making decisions

Question 10

how is the parahippocampal gryus associated with OCD?

Answer 10

there is some evidence to suggest that the parahippocampal gryus, associated with processing unpleasant emotions, functions abnormally in OCD

Question 11

evaluation: research support

Answer 11

• antidepressant that work purely on serotonin are effective in reducing OCD symptoms, which suggests that serotonin may be involved in OCD
• hibar et al (2018) found evidence of a significant positive concordance between OCD risk variants and variants associated with greater nucleus accumbens and putamen volumes
• this suggests that biological factors may be responsible for OCD

Question 12

evaluation: serotonin-OCD link may not be unique to OCD

Answer 12

• many people with OCD also experience clinical depression
• having two disorders together is called co-morbidity
• this depression involves, though is not necessarily caused by, disruption to the action of serotonin
• therefore, serotonin activity could be disrupted in many people with OCD because they are depressed as well

Question 13

evaluation: correlation and causality

Answer 13

• according to the biological model of mental disorder, brain dysfunction is explained to cause the OCD
• however, this is simply a correlation between neural abnormality and OCD, and such correlations do not necessarily indicate a causal relationship
• it is quite possible that the OCD (or its accompanying depression) causes the abnormal brain function or both are influenced by a third factor

Question 14

evaluation: research into areas of the brain

Answer 14

• advances in technology have allowed researchers to investigate specific areas of the brain more accurately, and OCD sufferers do seem to have excessive activity in the OFC and other key areas
• the repetitive acts (compulsions) may be explained by the structural abnormality of the basal ganglia, but not necessarily the obsessional thoughts
• there are inconsistencies found in the research as no system has been found that always plays a role in OCD; multiple areas and structures are implicated and the role will vary from person to person
• these neural changes could be as a result of suffering from the disorder, not necessarily the cause of it