Secondary objectives
Secondary objectives of this study comprise to evaluate 
• Whether methylphenidate immediate release given BID is significantly superior to placebo in the treatment of manic symptoms in patients with bipolar disorder after 2 hours of treatment as assessed by the YMRS and the Positive and Negative Syndrome scale - excited component (PANSS-EC) [42].
• The change from baseline to endpoint (after 2.5 days of treatment) on the Clinical Global Impression-Bipolar Scale CGI-BP [43] and the PANSS-EC.
• Whether 2.5 days of treatment with methylphenidate but not with placebo stabilise vigilance regulation as assessed by the ‘Vigilance Algorithm Leipzig’ (VIGALL) [44].
Whether instability of vigilance regulation as assessed by the VIGALL predicts response to methylphenidate.
• Whether methylphenidate immediate release given BID is associated with significantly less movements over the study period than placebo as assessed by actigraphy.
• Whether methylphenidate is significantly superior to placebo in improving cognitive performance as assessed by the “Screen for Cognitive Impairment in Psychiatry” (SCIP) [45].