Antipsychotic drugs targeting dopamine D2 receptors may affect the positive symptoms of schizophrenia; however, drugs targeting non-DA D2 receptors (DA D1, D3 and D4), serotonin receptors (5-HT2A, 5-HT1A, 5-HT3, 5-HT6, 5-HT7), alpha-adrenergic receptors and other neurotransmitters are considered effective treatments for the negative symptoms of schizophrenia20,21. This evidence concerns the gene HTR1A and schizophrenia.