Associations Between Morningness/eveningness and Psychopathology: An Epidemiological Survey in Three in-Patient Psychiatric Clinics.

Associations between morningness/eveningness and psychopathology: An epidemiological survey in three in-patient psychiatric clinics.

J Psychiatr Res. 2013 Apr 27;
Lemoine P, Zawieja P, Ohayon MM

OBJECTIVE: This study aims to examine the association between the chronotype (morningness/eveningness) and specific mental disorders. METHODS: Cross-sectional epidemiological study conducted in three in-patient clinical settings. A total of 1468 consecutive in-patients who gave their written consent were enrolled. On the admission day, patients filled sleep questionnaires and a nurse filled a Clinical Global Impressions scale. Hospitalization reports and ICD-10 diagnoses were collected. RESULTS: Sleep/wake schedule was similar between the psychiatric diagnoses. On the other hand, morning type patients had an earlier bedtime, earlier wakeup time and shorter sleep duration than the other chronotype regardless of the diagnosis. In multivariate models, patients with a depressive disorder or a psychosis were more likely to be morning type. Patients with an anxiety disorder, addiction disorder or personality disorder were more likely to be evening type. CONCLUSIONS: Age and sleep/wake schedule are contributing factors for the chronotype but mental disorders too appeared to modulate chronotype preferences. HubMed – addiction


Negative reinforcement in drug addiction: the darkness within.

Curr Opin Neurobiol. 2013 Apr 26;
Koob GF

Drug seeking is associated with the activation of reward neural circuitry, but I argue that drug addiction also involves another major source of reinforcement, specifically negative reinforcement driven by the ‘dark side’ (i.e., a decrease in the function of normal reward-related neurocircuitry and persistent recruitment of the brain stress systems). This combination forms the antireward system or ‘darkness within.’ Understanding the neuroplasticity of the neurocircuitry that comprises the negative reinforcement associated with addiction is the key to understanding the vulnerability to the transition to addiction, misery of addiction, and persistence of addiction. HubMed – addiction


Optogenetic insights into striatal function and behavior.

Behav Brain Res. 2013 Apr 26;
Lenz JD, Lobo MK

Recent breakthroughs in optogenetic technologies to alter neuronal firing and function with light, combined with cell type-specific transgenic animal lines, has led to important insights into the function of distinct neuronal cell subtypes and afferent connections in the heterogeneously complex striatum. A vital part of the basal ganglia, the striatum is heavily implicated in both motor control and motivation-based behavior; as well as in neurological disorders and psychiatric diseases including Parkinson’s Disease, Huntington’s Disease, drug addiction, depression, and schizophrenia. Researchers are able to manipulate firing and cell signaling with temporal precision using optogenetics in the two striatal medium spiny neuron (MSN) subpopulations, the striatal interneurons, and striatal afferents. These studies confirmed the classical hypothesis of movement control and reward seeking behavior through direct versus indirect pathway MSNs; illuminated a selective role for TANs in cocaine reward; dissected the roles of glutamatergic and dopaminergic inputs to striatum in reward; and highlighted a role for striatal signaling molecules including an adrenergic G-protein coupled receptor in reward and the rho-GTPase Rac1 in cocaine reward and cocaine induced structural plasticity. This review focuses on how the evolving optogenetic toolbox provides insight into the distinct behavioral roles of striatal cell subpopulations and striatal afferents, which has clinically relevant implications into neurological disorders and psychiatric disease. HubMed – addiction


The Effects of Cannabis Use Expectancies on Self-Initiated Cannabis Cessation.

Addiction. 2013 Apr 30;
Boden MT, McKay JR, Long WR, Bonn-Miller MO

AIMS: To prospectively investigate the relation between cannabis use expectancies and cannabis use prior to and during a self-initiated cannabis cessation attempt. DESIGN: Cohort design that followed participants for four weeks following a self-initiated cessation attempt. SETTING: United States Department of Veterans Affairs medical center. PARTICIPANTS: 100 cannabis dependent military veterans. MEASUREMENTS: The Marijuana Effects Expectancy Questionnaire [1] at baseline. The timeline follow-back procedure [2] at baseline and during the cessation attempt. FINDINGS: Cannabis use at baseline was associated with positive (p = .01), but not negative expectancies (p = .25). Cannabis lapse was associated with positive (p = .03) and negative expectancies (p = .01), and relapse was associated with positive (p = .04), but not negative expectancies (p = .21). The trajectory of average cannabis use during the cessation period was associated with positive (p = .03), but not negative expectancies (p = .96). Results were similar in effect and statistical significance when adjusting for demographic factors, motivation to quit cannabis, mental disorder diagnoses, and alcohol and tobacco use, and when analyzing complete data sets obtained through multiple imputation. CONCLUSIONS: In the United States, cannabis use expectancies, especially those regarding the positive effects of cannabis use, appear to be strongly and consistently linked to cannabis use and quit failure. HubMed – addiction