Beginning which dose can ritalin (methylphenidate) make you psychotic ? which dose is considered risky ?

If you have bipolar: Disorder or a bipolar predisposition than it would be possible for any dose of Ritalin (methylphenidate) or other stimulant to trigger mania or hypomania. Psychosis can sometimes occur with mania.

Depends on person: Most people would not experience psychosis except at very high doses if at all. A few may become psychotic or manic at very low doses. Management by a psychiatrist who can observe symptoms clinically is crucial. A history of psychotic or manic symptoms, or a family history of these would be reason for extra caution.