A Human Tolerance Review Found Different Degrees of Adaptation Across Cognitive and Cardiac Outcomes

A 2018 systematic review found evidence that tolerance varied across human response domains. Its synthesis described stronger cognitive adaptation in some studies than attenuation of intoxicating, psychotomimetic or cardiac effects.

The evidence included two comparison types

Some studies compared people with different cannabis-use histories; others examined repeated administration. A between-group difference and within-person adaptation do not have identical causal strengths. The study design should remain attached to each conclusion.

Full tolerance was an outcome-specific finding

The review described some evidence of absent acute effects within selected cognitive comparisons, while other responses were only partly blunted. This does not establish full tolerance in every cognitive domain, every regular user or every exposure condition.

An aggregate conclusion is not a personal test

Volunteer selection, task, dose and prior history affect how the findings can be applied. A person's use frequency does not independently establish the degree of adaptation on a particular function. A lower group response also does not necessarily mean no meaningful residual effect.

Interpreting the evidence

The synthesis supports specifying the domain and degree of tolerance instead of using a global label. It does not establish that regular use protects against all adverse effects or provide an individual impairment threshold.

Related reading: interpreting cannabis tolerance claims.

Research reference

Colizzi M; Bhattacharyya S (2018). Cannabis use and the development of tolerance: a systematic review of human evidence. Neuroscience and biobehavioral reviews. doi:10.1016/j.neubiorev.2018.07.014.

This analysis draws on the supplied review abstract.