"paraesthesias" occur, feeling like "electric shocks" in the head. Other symptoms include: sweating , nausea , insomnia , tremor , confusion , nightmares , and vertigo agitation, anxiety, akathesia , panic attacks , irritability, hostility, aggressiveness, worsening of mood, dysphoria (unhappiness), crying spells, mood instability, hyperactivity, depersonalization , decreased concentration, slowed