OCD L5

OCD is an anxiety disorder characterised by intrusive and uncontrollable thoughts – obsessions – coupled with a need to perform specific acts repeatedly – compulsions. 

Common clinical obsessions:  

  • Fear of contamination. 

  • Repetitive thoughts of violence. 

  • Sexual obsessions. 

  • Obsessive doubt.  

Common compulsions: 

  • Cleaning. 

  • Washing. 

  • Counting.  

  • Touching. 

Cognitive themes: 

Obsessive thoughts 

Recognize that it's excessive or unreasonable. 

Emotional: 

Obsessive thoughts lead to anxiety, worry and distress 

Behaviors: 

Compulsions are carried out through their behavior. 

Know that their compulsions are excessive or unreasonable but belive something bad will happen if they don't perform that behavior.  

Weaknesses: 

Don't look at the environment – people aren't born with OCD. Could be learnt through the process of classical (association) and operant (reinforcement/punishment) conditioning. 

Biological factors are reductionist as they focus only on one factor. So, its oversimplified, other factors such as cognition are ignored. 

Biological explanations are deterministic because they ignore the individual's ability to control their own behavior within then may affect their biochemistry levels. 

Strengths: 

Good testability with neuroscience research. 

We have evidence for genetic and neurotransmitter involvement in conditions.  

 

Genetic explanations: 

OCD is thought to be polygenic condition (number of genes are involved in its development).  

Use family and twin studies when studying OCD. If both develop their genetics. 

SERT gene (serotonin) appears to be mutated in individuals with OCD, the mutation causes an increase in transporter proteins at a neuron's membrane. This leads to an increase in the reuptake of serotonin in the neuron which decreases the level of serotonin in the synapse.  

The COMT gene regulates dopamine. It appears that this gene is also mutated in individuals with OCD. However, this mutation causes the opposite effect as the SERT mutation discussed above. The mutated variation of the COMT gene found in OCD individuals decreases COMT activity and thus a higher level of dopamine.  

Evaluation of the genetic explanation of OCD: 

Carey and Gottesman – Found that identical twins showed a concordance rate of OCD for 87% and only 47% in non-identical twins. It suggests it is related to biological factors but shows there are other factors.  

The higher concordance rate found for identical twins may be due to nurture as identical twins are likely to experience a more similar environment than fraternal twins since they tend to be treated the same.   

Genes don't determine who will develop OCD. Could have a genetic predisposition but it may never be triggered.  

OCD could be cultural rather than genetically transmitted as the family members may observe and imitate each other's behavior, as predicted by social learning theory.  

Alternatively, family members might be more vulnerable to OCD because of the stressful environment rather than because of genetic factors.  

Neral explanations: 

How does brain structure relate to OCD. 

Prefrontal cortex – is involved in decision making. If you have overactive prefrontal cortex, you are more likely to develop OCD/if you have OCD prefrontal cortex is likely to be overactive. 

Abnormalities or an imbalance in the neurotransmitter serotonin could also be related to OCD, Reduced serotonin and excessive dopamine may cause OCD. 

Serotonin is the chemical throught to be involved in regulating mood. OCD patients have low levels of serotonin. 

Dopamine is abnormally high in individuals with OCD. 

Evaluation of neural explanations of OCD: 

The brains of OCD patients are structured and function differently from those of other people. (salloway and duffy) 

Whether low serotonin causes OCD is unknown. All is known is that they are related, we don't know which comes first. Just a relationship/correlation but it's not a causation. 

We don't know whether high levels of dopamine cause OCD or whether OCD causes high levels of dopamine.  

The biochemistry hypothesis does not account for individual differences because OCD and another develops different mental disorder because low serotonin levels are also found in other disorders. Serotonin isn't only OCD. 

Psychological therapy can be a very successful treatment, and this is difficult to account for in the serotonin hypothesis.  

 

Biological treatments of OCD: 

SRIs – Serotonin reuptake inhibitors. 

SSRIs – Selective serotonin reuptake inhibitors. 

Drugs that don't focus on serotonin didn't help in treating OCD. Suggests serotonin is a main factor. 

Evaluation of biological treatment: 

Studies have shown a reduction in dopamine levels is positively correlated with a reduction in OCD symptoms.  

Experiments that inject animals with drugs that increase levels of dopamine have caused the animals to demonstrate OCD type behaviors. 

Drugs that increase serotonin (SSRIs) have been shown to reduce OCD symptoms. Soomro et al. Found that SSRIs were significantly better than placebos in reducing symptoms in 17 different clinical trials.  

But in research results relating to serotonin are varied – sometimes symptoms have been made worse. There is a great deal of contradictory research.  

Drugs seem to show only partial alleviation of the symptoms, so the process is not fully understood. The exact function of neurotransmitters in the development of OCD is fat from understood.  

Most SSRIs have side effects that can be unpleasant e.g. dry mouth a slight tremor fast heartbeat constipation sleepiness and weight gain. 

The success of antidepressant drugs as a treatment does not necessarily mean the Biochemicals are the cause of OCD in the first place. This is known as the treatment etiology fallacy and using headaches as an example, aspirin works well as a treatment, but this doesn't mean the headache was due to an absence of aspirin.