What are catecholamines?

Catecholamines are a group of neurotransmitters that includes dopamine and noradrenaline. The dopamine hypothesis of schizophrenia suggests that some symptoms of the illness may be caused by increased levels of dopamine in certain brain areas. To this end, most antipsychotic medications typically have dopamine-blocking actions. However, these medications do not treat all of the symptoms of schizophrenia, and it is thought that some of the remaining symptoms may be affected by the low levels of dopamine resulting from medication. Consequently, the effects of medications that increase dopamine levels, in addition to ongoing antipsychotic medications, have been investigated as a treatment for general symptoms.

What is the evidence for catecholamines?

Moderate to low quality evidence finds a medium-sized benefit of L-DOPA over placebo for improving overall symptom severity. There may also be a benefit for tardive dyskinesia with dopaminergic medications, with no differences compared to placebo in levels of acceptability.

Large benefits were found for mirtazapine or mianserin for improving total and negative symptoms, but not for improving general or positive symptoms. Review authors report that the treatment was well tolerated.

Some benefits were also found for noradrenergic reuptake inhibitors over placebo for general symptoms in the short-term (2-12 weeks) and negative symptoms in the medium-term (13-26 weeks). There may also be some improvements in quality of life with noradrenergic medications, with no differences compared to placebo in levels of nausea.

September 2020

Last updated at: 4:47 am, 29th September 2020
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Title Colour Legend:
Green - Topic summary is available.
Orange - Topic summary is being compiled.
Red - Topic summary has no current systematic review available.