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Vogel AP, Pearson-Dennett V, Magee M, Wilcox RA, Esterman A, Thewlis D, White JM, Todd G. Adults with a history of recreational cannabis use have altered speech production. Drug Alcohol Depend 2021; 227:108963. [PMID: 34419853 DOI: 10.1016/j.drugalcdep.2021.108963] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 06/18/2021] [Accepted: 07/07/2021] [Indexed: 11/28/2022]
Abstract
Stereotypical depictions of speech in cannabis users often suggest slow, laboured output, yet objective evidence supporting this assumption is extremely limited. We know that depressants or hallucinogenic drugs such as cannabis can cause acute changes in communication and speech rate, but the long-lasting effects of cannabis use on speech are not well described. The aim of this study was to investigate speech in individuals with a history of recreational cannabis use compared to non-drug-using healthy controls. Speech samples were collected from a carefully described cohort of 31 adults with a history of cannabis use (but not use of illicit stimulant drugs) and 40 non-drug-using controls. Subjects completed simple and complex speech tasks including a monologue, a sustained vowel, saying the days of the week, and reading a phonetically balanced passage. Audio samples were analysed objectively using acoustic analysis for measures of timing, vocal control, and quality. Subtle differences in speech timing, vocal effort, and voice quality may exist between cannabis and control groups, however data remain equivocal. After controlling for lifetime alcohol and tobacco use and applying a false discovery rate, only spectral tilt (vocal effort and intensity) differed between groups and appeared to change in line with duration of abstinence from cannabis use. Differences between groups may reflect longer term changes to the underlying neural control of speech. Our digital analysis of speech shows there may be a signal differentiating individuals with a history of recreational cannabis use from healthy controls, in line with similar findings from gait and hand function studies.
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Affiliation(s)
- Adam P Vogel
- Centre for Neuroscience of Speech, The University of Melbourne, Parkville, VIC, 3010, Australia; Department of Neurodegeneration, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, 72076, Germany; Redenlab, Melbourne, Australia.
| | - Verity Pearson-Dennett
- UniSA Clinical & Health Sciences, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia
| | - Michelle Magee
- Centre for Neuroscience of Speech, The University of Melbourne, Parkville, VIC, 3010, Australia; Redenlab, Melbourne, Australia
| | - Robert A Wilcox
- UniSA Clinical & Health Sciences, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia; Department of Neurology, Flinders Medical Centre, Bedford Park, SA, 5042, Australia; Human Physiology, Medical School, Flinders University, Bedford Park, SA, 5042, Australia
| | - Adrian Esterman
- UniSA Clinical & Health Sciences, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia; Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | - Dominic Thewlis
- Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, SA, 5000, Australia
| | - Jason M White
- UniSA Clinical & Health Sciences, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia
| | - Gabrielle Todd
- UniSA Clinical & Health Sciences, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia; Alliance for Research in Exercise, Nutrition and Activity (ARENA), UniSA Allied Health & Human Performance, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia.
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