Neuroleptic Induced Deficit Syndrome is a clinical syndrome that develops in some patients taking too high dose of an antipsychotic for too long time [1] It is most often caused by high-potency typical_antipsychotics, but can also be caused by high doses of many atypicals, especially those which are closer in profile to typical ones (i.e. have higher D2 dopamine receptor affinity and relatively low 5-HT2 serotonin receptor binding affinity), like risperidone and amisulpride.
Neuroleptic induced deficit syndrome is characterized by principally the same symptoms that constitute the negative symptoms of schizofrenia - emotional blunting, apathy, hypobulia, difficulty in thinking, difficulty or total inability in concentrating attention, autism, desocialization. This can easily lead to misdiagnosis and mistreatment - instead of decreasing the antipsychotic, the doctor may try to increase their dose in order to try to "improve" what he perceives to be negative symptoms of schizofrenia, rather than antipsychotic side effects.