Primary Mental Disorders
Phencyclidine-Induced Disorders may be characterized by symptoms (e.g., depressed mood) that resemble primary mental disorders (e.g., Major Depressive Disorder versus Phencyclidine-Induced Mood Disorder, With Depressive Features, With Onset During Intoxication). Recurring episodes of psychotic or mood symptoms due to Phencyclidine Intoxication may mimic Schizophrenia or Mood Disorders. History or laboratory evidence of phencyclidine use establishes a role for the substance, but does not rule out the co-occurrence of other primary mental disorders. Rapid onset of symptoms also suggests Phencyclidine Intoxication rather than Schizophrenia, but phencyclidine use may induce acute psychotic episodes in individuals with preexisting Schizophrenia. Rapid resolution of symptoms and the absence of a history of Schizophrenia may aid in this differentiation. Drug-related violence or impaired judgment may co-occur with, or may mimic aspects of, Conduct Disorder or Antisocial Personality Disorder. Absence of behavioral problems before the onset of substance use, or during abstinence, may help to clarify the differentiation.
Phencyclidine and related substances may produce perceptual disturbances (e.g., scintillating lights, perception of sounds, illusions, or formed visual images) that the person usually recognizes as resulting from the drug use. If reality testing remains intact and the person neither believes that the perceptions are real nor acts on them, the specifier With Perceptual Disturbances is noted for Phencyclidine Intoxication. If reality testing is impaired, the diagnosis of Phencyclidine-Induced Psychotic Disorder should be considered.
Differentiating Phencyclidine Intoxication from other Substance Intoxications (with which it often coexists) depends on a history of having taken the substance, the presence of characteristic findings (e.g., nystagmus and mild hypertension), and positive urine toxicological tests. Individuals who use phencyclidine often use other drugs as well, and comorbid Abuse or Dependence on other drugs must be considered. Phencyclidine Intoxication is distinguished from the other Phencyclidine-Induced Disorders (e.g., Phencyclidine-Induced Mood Disorder, With Onset During Intoxication) because the symptoms in these latter disorders are in excess of those usually associated with Phencyclidine Intoxication and are severe enough to warrant independent clinical attention.