3.3.1 Bio exp.1: Dopamine Hypothesis Evaluation

Question 1

What role might genes play in dopamine imbalances?

Answer 1

• Genes may influence dopamine imbalances
• Twin and family studies, like Gottesman et al. (1991), show that the more genetically similar two people are, the more likely both are to develop schizophrenia

Question 2

Is schizophrenia caused by just a few dopamine-related genes?

Answer 2

No.

A 2014 study by the Psychiatric Genomics Consortium found 108 genetic loci linked to schizophrenia, showing it is genetically complex, not caused by just a few dopamine-related genes.

Question 3

How are dopamine levels typically measured in research?

Answer 3

• By analysing metabolites like HVA (homovanillic acid) in cerebrospinal fluid, collected through a lumbar puncture
• This process is invasive and results can be influenced by diet and drug use

Question 4

What are some problems with using metabolites to measure dopamine levels?

Answer 4

• Results can vary widely between people and are affected by outside factors
• This makes it hard to draw solid conclusions, so caution is needed when interpreting the data

Question 5

Is dopamine the only neurotransmitter involved in schizophrenia?

Answer 5

No.
- Serotonin is also involved
- Atypical antipsychotics like clozapine block both dopamine (D2) and serotonin (5-HT2A) receptors, suggesting that dopamine alone doesn’t fully explain schizophrenia

Question 6

Could schizophrenia cause dopamine imbalances instead of the other way around?

Answer 6

Yes, it’s possible.

Dopamine imbalances might be a symptom of schizophrenia rather than a cause. Research hasn’t yet proven which comes first

Question 7

What have brain scans like PET scans shown about dopamine activity in schizophrenia?

Answer 7

PET scans (e.g., Copolov & Crook, 2000) haven’t clearly detected dopamine differences between people with and without schizophrenia, so we still don’t know the direction of the relationship