specifically for Xanax:
"Psychological symptoms: anxiety** (including panic attacks), depression**, insomnia*, derealization/depersonalization* (feelings of unreality/detachment from self), abnormal sensitivity sensory stimuli* (such as loud noise or bright light),
obsessive negative thoughts*, (particularly of a violent and/or sexual nature) rapid mood changes* (including especially outbursts of anger or rage), phobias* (especially agoraphobia and fear of insanity), dysphoria* (loss of capacity to enjoy life; possibility a combination of depression, anxiety, and derealization/depersonalization), impairment of cognitive functioning*, suicidal thoughts*, nightmares, hallucinations, psychosis, pill cravings. Note that it is far more common to fear psychosis than it is to actually experience it. Physical Symptoms: muscle tension/pain**, joint pain*, tinnitus*, headaches*, shaking/tremors*, blurred vision* (and other complications related to the eyes), itchy skin* (including sensations of insects crawling on skin), gastrointestinal discomfort*, electric shock sensations*, paresthesia* (numbness and pins and needles, especially in extremities), fatigue*, weakness in the extremities (particularly the legs)*, feelings of inner vibrations* (especially in the torso), sweating, fluctuations in body temperature, difficulty in swallowing, loss of appetite, "flu like" symptoms, fasciculations (muscle twitching), metallic taste in mouth, nausea, extreme thirst (including dry mouth and increased frequency of urination), sexual dysfunction (or occasional increase in libido), heart palpitations, dizziness, vertigo, breathlessness.
What has become clinically apparent with Xanax which appears to be somewhat different than the other benzodiazepines is that the patients ability to self-detox or be able to be gradually tapered off of the medication is markedly more difficult. Thusly, once the physiologic dependence has occurred with Xanax, the ability of the patient to discontinue use successfully on their own is quite low, and medical assistance becomes of significant necessity in the majority of cases."
http://www.oxyabusekills.com/xanax.htmlonedit: I can vouch for the "outbursts" effect of Xanax withdrawal. It's some nasty shit.