Antipsychotics are a group of rugs commonly but not exclusively used to treat psychosis. Conditions for which antipsychotic drugs might be used include schizophrenia, bipolar disorder, mania, and delusional disorder. Over time different classes of antipsychotics have been developed. A first generation of antipsychotics, known as typical antipsychotics, were discovered in the 1950s. Most of the drugs in the second generation of antipsychotics, known as atypical antipsychotics, have more recently been developed and come into use. Both classes of medication tend to block receptors in dopamine pathways in the brain. A number of side effects have been observed in relation to specific medications, including weight gain, agranulocytosis, tardive dyskinesia, tardive akathisia and tardive psychoses. The relative efficacy of typical versus atypical antipsychotics along various dimensions has recently been a subject of study and to a certain extent remains to be understood.