Why does methamphetamine cause paranoia

Methamphetamine psychosis

An Australian research team determined the risk of psychotic symptoms in a longitudinal study. In phases of increased methamphetamine use, the people involved had a 5-fold higher risk of psychosis than if they were abstinent.

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Delusions and hallucinations are typical psychotic symptoms that can occur when using methamphetamine (crystal). So far, however, it is unclear whether the symptoms are actually the result of consumption. It is conceivable that certain people have a tendency to psychotic symptoms anyway and that consumption is more the result of this tendency.

To get more clarity on this, an Australian research team carried out a longitudinal study. 278 methamphetamine users were examined four times over a period of 3 years. In each case, it was about the last month before the survey.

All subjects were dependent on methamphetamine at the first measurement time. Many of those involved received treatment over the entire study period. This included episodes of intense consumption as well as periods of abstinence. The research team led by study director Rebecca McKetin was therefore able to determine how high the risk of psychosis is in the consumption and abstinence phases.

Dose-dependent relationship

The evaluations showed a 5-fold increased risk of psychosis if the persons had consumed methamphetamine in the last month. The risk had a clear dose-response relationship. This means: the more it was consumed, the higher the likelihood of psychotic symptoms. If the drug was consumed on more than 15 days per month, the risk of psychosis was even 11 times higher. The parallel consumption of alcohol and cannabis also had a significant influence on the risk of psychosis.

In their specialist article, the research team writes that this has still not formally proven that methamphetamine triggers psychotic symptoms. The clear dose-dependent relationship between the frequency of use and the extent of psychotic symptoms would, however, provide strong evidence for this.

Persistent psychosis

For most of those affected, the symptoms usually disappeared during periods of abstinence. However, a minority continued to suffer from psychotic symptoms. The use of methamphetamine could be particularly risky for this group of people, as they may develop a permanent psychosis such as schizophrenia.

McKetin, R., Lubman, D. I., Baker, A., Dawe, S. & Ali, R. L. (2013). Dose-Related Psychotic Symptoms in Chronic Methamphetamine Users. JAMA Psychiatry, Online first January 9, 2013, doi: 10.1001 / jamapsychiatry.2013.283.