why does genetics basis of explanation of schizophrenia lack validity

Do you mean the dopamine hypothesis or Gottesman and Shields

For Gottesman and Shields, you can look at the Diathesis-Stress model. Basically, because the concordance rates for the MZ twins was only 75% not 100% schizophrenia is not entirely caused by genetics but also but environment, therefore, it's epigenetic.

For the dopamine hypothesis, you gotta refute it by looking at explanations of serotonin levels for positive and negative symptoms of Sz. Clozapine is a drug that doesn't affect Dopamine or Glutamate.

clozapine is an antipsychotic so it does affect the dopamine levels in the brain

"Clozapine is classified as an atypical antipsychotic drug because it binds to serotonin as well as dopamine receptors. Clozapine is an antagonist at the 5-HT2A subunit of the serotonin receptor, putatively improving depression, anxiety, and the negative cognitive symptoms associated with schizophrenia"

I think it's still valid as a refuting argument because it shows that dopamine is not solely responsible?

Yes i agree with you but you mentioned in your previous post that it doesn’t affect dopamine levels - it was abit unclear what you meant, that’s all

No they didn't, they said it 'mainly affects serotonin instead of just dopamine'.

both

& look what it says below that 🤡 they’ve edited it!

You can specifically talk abt the way the study was conducted that lacked validity- eg -maybe the fact that they conducted Interviews and social desirability might be at play here, which might make the results unreliable

You can also talk abt other factors which are more general: The genetic basis is reductionist- it oversimplifies complex behaviours such as delusions/hallucinations and other symptoms of schizophrenia to just biological processes- wherein it could have been affected by the environment as well (the user above mentioned some statistics which you could use to strengthen your argument) In CIE we don't need to remember the stats for A2, so idk if you're required to

You can also talk about determinism, lack of qualitative data and apply it to the genetic explanations using supporting evidence.
Hope this helps!