Evidence map›Paper›PMID 27125202›Full record

SynthesisNeuropsychology review2016

Weighing the Evidence: A Systematic Review on Long-Term Neurocognitive Effects of Cannabis Use in Abstinent Adolescents and Adults.

Florian Ganzer, Sonja Bröning, Stefanie Kraft, Peter-Michael Sack, Rainer Thomasius

Abstract readSystematic Review
PubMed Publisher
In one paragraph

Synthesis in Neuropsychology review, 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 61 papers, 6 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
61citing papers in PubMed, 6 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

61 citing papers in PubMed, 6 syntheses or guidelines pooled it.

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1 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Florian GanzerDeutsches Zentrum für Suchtfragen des Kindes- und Jugendalters (DZSKJ; German Center for Addiction Research in Childhood and Adolescence), University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246, Hamburg, Germany. f.ganzer@uke.de.
Sonja BröningDeutsches Zentrum für Suchtfragen des Kindes- und Jugendalters (DZSKJ; German Center for Addiction Research in Childhood and Adolescence), University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246, Hamburg, Germany.
Stefanie KraftDeutsches Zentrum für Suchtfragen des Kindes- und Jugendalters (DZSKJ; German Center for Addiction Research in Childhood and Adolescence), University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246, Hamburg, Germany.
Peter-Michael SackDeutsches Zentrum für Suchtfragen des Kindes- und Jugendalters (DZSKJ; German Center for Addiction Research in Childhood and Adolescence), University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246, Hamburg, Germany.
Rainer ThomasiusDeutsches Zentrum für Suchtfragen des Kindes- und Jugendalters (DZSKJ; German Center for Addiction Research in Childhood and Adolescence), University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246, Hamburg, Germany.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Findings on neurocognitive effects of sustained cannabis use are heterogeneous. Previous work has rarely taken time of abstinence into account. In this review, we focus on understanding sustained effects of cannabis, which begin when clinical symptoms of the drug have worn off after at least 14 days. We conducted a search between 2004 and 2015 and found 38 studies with such a prolonged abstinence phase. Study-design quality in terms of evidence-based medicine is similar among studies. Studies found some attention or concentration deficits in cannabis users (CU). There is evidence that chronic CU might experience sustained deficits in memory function. Findings are mixed regarding impairments in inhibition, impulsivity and decision making for CU, but there is a trend towards worse performance. Three out of four studies found evidence that motor function remains impaired even after a time of abstinence, while no impairments in visual spatial functioning can be concluded. Functional imaging demonstrates clear differences in activation patterns between CU and controls especially in hippocampal, prefrontal and cerebellar areas. Structural differences are found in cortical areas, especially the orbitofrontal region and the hippocampus. Twenty studies (57 %) reported data on outcome effects, leading to an overall effect size of r mean = .378 (CI 95 % = [.342; .453]). Heavy use is found to be more consistently associated with effects in diverse domains than early age of onset. Questions of causality-in view of scarce longitudinal studies, especially those targeting co-occurring psychiatric disorders-are discussed.

Indexed as

AdolescentAdultCannabisHumansMarijuana AbuseCannabisCognitive effectsMarijuanaNeuropsychologySystematic reviewTHC

Identifiers

PMID27125202

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.