What kind of medical treatment existed for schizophrenia in the 1960s and 1970s?

As there was no known cure, sufferers were subject to trial and error treatments - these weren't very effective, and some of them had gruesome side effects.
One treatment involved injecting the patient with sulphur and oil.

Brain surgery and electric shock therapy were common for treating Schizophrenia in the 1950s/60's.

People were isolated and given large amounts of sedatives. Early sedatives had a calming effect but could cause tremors in the arms and legs - similar to those caused by Parkinson's Disease.

70% of people diagnosed were institutionalised for the rest of their lives because they had become too dependant upon the hospital.

Then in 1952 two French psychiatrists, Jean Delay and Paul Deniker tried prescribing chlorpromazine for schizophrenia and found that it had a calming effect on their patients that was significantly different from the effects of the tranquillisers that had been widely used before for this condition. Rather than simply blunting the effect of the hallucinations this drug did actually seem to reduce the symptoms altogether. - Use site https://www..org/advice-sheets/schizophrenia-a-brief-history/ - it gives more detail and information.