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EEG of chronic marijuana users during abstinence: relationship to years of marijuana use, cerebral blood flow and thyroid function.

Ronald I. Herning, Warren Better, Jean L Cadet

Clinical Neurophysiology February 2008 DOI: 10.1016/j.clinph.2007.09.140 (opens in new tab)

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Characteristics Observational study Peer reviewed
Sample size 108
Population 75 abstinent marijuana users and 33 control subjects
Duration EEG within 72 hours of admission; 59 marijuana users remained abstinent for a month and were tested twice
Measures EEG (log alpha2 and beta2 power at posterior sites), heart rate, thyroid function (T4)
Topics Cannabis
Key findings Marijuana users who used for eight years or more showed significantly lower log alpha2 and beta2 power at posterior EEG sites than shorter-term users and controls, and these changes persisted for a month of abstinence. They also had lower heart rates and thyroid function (T4). The authors suggest these reductions may relate to cerebral perfusion deficits and/or thyroid function, reflecting under-arousal.

Abstract

Marijuana abuse is associated with neurological changes including increases in frontal EEG alpha during abstinence. Research is needed to assess to what extent these EEG patterns are indicative of cerebral perfusion deficits. We recorded the resting eyes closed EEG of 75 abstinent marijuana users and 33 control subjects. Fifty-six marijuana users used marijuana for less than eight years and 19 used for eight years or more. The EEG evaluation occurred within 72h of admission to an inpatient unit. Fifty-nine marijuana users remained abstinent for a month and were tested twice. Supplemental psychological and physiological data were also collected. Log alpha2 and beta2 power at posterior sites were significantly lower for the marijuana abusers that used eight years or more than the other marijuana abusers and the control subjects. These EEG changes continued for the month of abstinence. The marijuana users who used marijuana for more than eight years, also, had lower heart rates and thyroid function (T4) compared to the other marijuana users and the control subjects. Chronic marijuana use was also associated with reduced EEG power in alpha and beta bands at posterior sites. These reductions in EEG power appear to be related to cerebral perfusion deficits and/or thyroid function in marijuana abusers. Our results suggest EEG, cerebral blood flow velocity, cardiovascular and thyroid function alterations in marijuana abuser with an extended period of use. These alterations reflect under arousal in these systems.

Comparable studies

Other observational and cohort studies on cannabis, most cited first.

Study Year Design Participants
High-potency cannabis and the risk of psychosis People with first episode of psychosis and healthy controls from the local population 2009 Case-control study n = 454
Ayahuasca-Assisted Therapy for Addiction: Results from a Preliminary Observational Study in Canada Rural aboriginal population 2013 Observational study
Impaired cognitive performance in drug free users of recreational ecstasy (MDMA) Otherwise healthy young people 2000 Observational
Continued cannabis use and risk of incidence and persistence of psychotic symptoms: 10 year follow-up cohort study Individuals from the general population in Germany aged 14-24 at baseline 2011 Observational cohort n = 1,923
Cannabis-induced psychosis and subsequent schizophrenia-spectrum disorders: follow-up study of 535 incident cases Patients treated for cannabis-induced psychotic symptoms in Denmark between 1994 and... 2005 Observational cohort n = 535

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