DRD2 and schizophrenia: Schizophrenia treatment is challenging because existing antipsychotics are antidopaminergic drugs that improve only positive symptoms such as agitation and aggression but have limited efficacy for negative and cognitive symptoms.385 Globally marketed antipsychotic drugs include typical antipsychotic drugs (mostly specific dopamine D2 receptor antagonists) and atypical antipsychotic drugs (such as dopamine D2 and 5-HT2A dual antagonists and D2/D3 partial agonists).