Do antipsychotic drugs and antihistamines make you gain weight?

Mostly, yes. Antipsychotics all have some antihistaminic properties. Almost all antipsychotics are associated with some weight gain. As with all prescription medication, the benefits and risks are an important part of the discussion between doc and pt. That prescription drugs are now being advertised to pts, in order to manipulate the physicians prescribing practices, is just one more abomination in the fld.
Weight. Yes, several do, especially older generation antipsychotics.