Stimulant psychosis

Drugs in the class of amphetamines, or substituted amphetamines, are known to induce "amphetamine psychosis" typically when chronically abused or used in high doses.[5] In an Australian study of 309 active methamphetamine users, 18% had experienced a clinical level psychosis in the past year.[6] Common amphetamines include cathinone, DOM, ephedrine, MDMA, methamphetamine, and methcathinone though a large number of such compounds have been synthesized. Methylphenidate is sometimes incorrectly included in this class, although it is nonetheless still capable of producing stimulant psychosis.

The symptoms of amphetamine psychosis include auditory and visual hallucinations, grandiosity, delusions of persecution, and delusions of reference concurrent with both clear consciousness and prominent extreme agitation.[7][8] A Japanese study of recovery from methamphetamine psychosis reported a 64% recovery rate within 10 days rising to an 82% recovery rate at 30 days after methamphetamine cessation.[9] However it has been suggested that around 5–15% of users fail to make a complete recovery in the long term.[10] Furthermore, even at a small dose, the psychosis can be quickly reestablished.[9] Psychosocial stress has been found to be an independent risk factor for psychosis relapse even without further substituted amphetamine use in certain cases.[11]

The symptoms of acute amphetamine psychosis are very similar to those of the acute phase of schizophrenia[5] although in amphetamine psychosis visual hallucinations are more common and thought disorder is rare.[12] Amphetamine psychosis may be purely related to high drug usage, or high drug usage may trigger an underlying vulnerability to schizophrenia.[5] There is some evidence that vulnerability to amphetamine psychosis and schizophrenia may be genetically related. Relatives of methamphetamine users with a history of amphetamine psychosis are five times more likely to have been diagnosed with schizophrenia than relatives of methamphetamine users without a history of amphetamine psychosis.[13] The disorders are often distinguished by a rapid resolution of symptoms in amphetamine psychosis, while schizophrenia is more likely to follow a chronic course.[14]

Although rare and not formally recognized,[15][16] a condition known as Amphetamine Withdrawal Psychosis (AWP) may occur upon cessation of substituted amphetamine use and, as the name implies, involves psychosis that appears on withdrawal from substituted amphetamines. However, unlike similar disorders, in AWP, substituted amphetamines reduce rather than increase symptoms, and the psychosis or mania resolves with resumption of the previous dosing schedule.[17]

Cocaine has a similar potential to induce temporary psychosis[18] with more than half of cocaine abusers reporting at least some psychotic symptoms at some point.[19] Typical symptoms of sufferers include paranoid delusions that they are being followed and that their drug use is being watched, accompanied by hallucinations that support the delusional beliefs.[19] Delusional parasitosis with formication ("cocaine bugs") is also a fairly common symptom.[20]

Cocaine-induced psychosis shows sensitization toward the psychotic effects of the drug. This means that psychosis becomes more severe with repeated intermittent use.[19][21]

Chronic abuse of methylphenidate can also lead to psychosis.[22][23] Psychotic symptoms from methylphenidate can include hearing voices, visual hallucinations, urges to harm oneself, severe anxiety, mania, grandiosity, paranoid delusions, confusion, increased irritability, and aggressive or violent behavior.

Similar psychiatric side effects have been reported with abuse of Ethylphenidate, a designer drug similar in pharmacology to its cousin drug.

There is limited evidence that caffeine, in high doses or when chronically abused, may induce psychosis in normal individuals and worsen pre-existing psychosis in those diagnosed with schizophrenia.[24][25][26]