Dramatic changes in perception, thought, and mood occur. While some users experience mild to intense euphoria, others feel threatened and because of fear, anxiety, or panic - can behave violently. The drug may also release hidden emotional or mental problems. Little is known about PCP's long-term effects , which appear after repeated use over a lengthy period. These are unpredictable, spontaneous recurrences of the original PCP trip without the user's having taken the drug again.
Flashbacks can occur weeks, months, or even up to a year after the last encounter with the drug.
Typically, they last only a few minutes, and are usually visual images ranging from formless colors to frightening hallucinations. Since the drug passes through the placenta, however, it may cause the signs of intoxication often observed for a few days after birth in babies born to PCP users. The drug is also excreted in the milk of nursing mothers. Little research has been done on whether PCP results in tolerance and dependence. Psychological dependence is suggested by the compulsive daily consumption of, and craving for, the drug by some users.