• Nervous system disorders Very common: dry mouth; headache Common: abnormal dreams; decreased libido; dizziness; increased muscle tonus; insomnia; nervousness; pins and needles; sedation; tremor; confusion; feeling separated (or detached) from yourself and reality Uncommon: lack of feeling or emotion; hallucinations; involuntary movement of the muscles; agitation; impaired coordination and balance Rare: a sensation of restlessness or an inability to sit or stand still; seizures or fits; feeling over- excited or euphoric Not known: a high temperature with rigid muscles, confusion or agitation, and sweating, or if you experience jerky muscle movements which you can't control, these may be symptoms of serious conditions known as neuroleptic malignant syndrome; euphoric feelings, drowsiness, sustained rapid eye movement, clumsiness, restlessness, feeling of being drunk, sweating or rigid muscles, which are symptoms of serotonergic syndrome; disorientation and confusion often accompanied by hallucination (delirium); stiffness, spasms and involuntary movements of the muscles; thoughts of harming or killing yourself