Article

Blue-yellow colour vision impairment and cognitive deficits in occasional and dependent stimulant users.

Experimental and Clinical Pharmacopsychology, Clinic for Affective Disorders and General Psychiatry, University Hospital of Psychiatry Zurich, Switzerland.
The International Journal of Neuropsychopharmacology (Impact Factor: 5.64). 06/2012; DOI:10.1017/S1461145712000624
Source: PubMed

ABSTRACT Specific blue-yellow colour vision impairment has been reported in dependent cocaine users and it was postulated that drug-induced changes in retinal dopamine neurotransmission are responsible. However, it is unclear whether these changes are confined to chronic cocaine users, whether they are specific for dopaminergic stimulants such as cocaine and amphetamine and whether they are related to cognitive functions such as working memory, encoding and consolidation. In 47 occasional and 29 dependent cocaine users, 23 MDMA (commonly known as 'ecstasy') users and 47 stimulant-naive controls, colour vision discrimination was measured with the Lanthony Desaturated Panel D-15 Test and memory performance with the Auditory Verbal Learning Test. Both occasional and dependent cocaine users showed higher colour confusion indices than controls. Users of the serotonergic stimulant MDMA (26%), occasional (30%) and dependent cocaine users (34%) exhibited more frequent blue-yellow colour vision disorders compared to controls (9%). Inferior performance of MDMA users was caused by a subgroup with high amphetamine co-use (55%), while MDMA use alone was not associated with decreased blue-yellow discrimination (0%). Cognitive performance was worse in cocaine users with colour vision disorder compared to users and controls with intact colour vision and both colour vision impairment and cognitive deficits were related to cocaine use. Occasional cocaine and amphetamine use might induce blue-yellow colour vision impairment, whereas the serotonergic stimulant MDMA does not impair colour vision. The association between colour vision impairment and cognitive deficits in cocaine users may reflect that retinal and cerebral dopamine alterations are linked to a certain degree.

0 0
 · 
0 Bookmarks
 · 
121 Views
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: Chronic cocaine users consistently display neurochemical and functional alterations in brain areas involved in social cognition (e.g. medial and orbitofrontal cortex). Although social functioning plays a crucial role in the development and treatment of drug dependence, studies investigating social cognition in cocaine users are lacking. Therefore, we investigated mental perspective taking ('theory of mind') and emotional and cognitive empathy in recreational (RCU) and dependent (DCU) cocaine users. Furthermore, we related these measures to real-life indicators of social functioning. One-hundred cocaine users (69 RCU, 31 DCU) and 68 stimulant-naïve healthy controls were tested with the Multifaceted Empathy Test (MET), Movie for the Assessment of Social Cognition (MASC) and Reading the Mind in the Eyes Test (RMET). The Social Network Questionnaire was conducted to assess social network size. Furthermore, participants provided information on committed criminal offenses. RCU and DCU showed less emotional empathy compared to controls (MET), whereas cognitive empathy was not impaired (MET, RMET). Additionally, DCU made more errors in mental perspective taking (MASC). Notably, cocaine users committed more criminal offenses and displayed a smaller social network and higher cocaine use was correlated with less social contacts. Diminished mental perspective taking was tentatively correlated with more intense cocaine use as well. Finally, younger age of onset of cocaine use was associated with more pronounced empathy impairment. In conclusion, social cognition impairments in cocaine users were related to real-life social functioning and should therefore be considered in therapy and prevention strategies.
    Addiction Biology 06/2013; · 5.91 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: BACKGROUND: Dependent cocaine users consistently display cognitive deficits but cognitive performance of recreational cocaine users has rarely been investigated. AIMS: To examine whether cognitive performance is impaired in relatively pure recreational and dependent cocaine users. METHOD: The cognitive performance of recreational (n = 68) and dependent cocaine users (n = 30) was compared with the performance of stimulant-naive controls (n = 68) employing an extensive neuropsychological test battery. Moreover, the impact of attention-deficit hyperactivity disorder (ADHD) symptoms, craving and early age at onset was analysed. RESULTS: Dependent cocaine users display broad cognitive impairments in the domains of attention, working memory, declarative memory and executive functions. The performance of recreational cocaine users in all four domains was intermediate between that of controls and dependent users and they displayed significant deficits foremost in the domains of attention and working memory. In addition, ADHD symptoms, craving and age at onset were important modulators of cognitive function in cocaine users. CONCLUSIONS: Cognitive deficits occur at a recreational and non-dependent level of cocaine use. Cocaine use and ADHD seem to have mutually aggravating effects on cognitive impairment.
    The British journal of psychiatry: the journal of mental science 05/2013; · 6.62 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: Maladaptive decision-making is assumed to be a core feature of cocaine addiction. Indeed, numerous studies have reported deficits in non-social decision-making tasks and reward-related impulsivity in dependent cocaine users. However, social decision-making has not been examined in cocaine users yet. Moreover, it is unknown if even recreational and non-dependent cocaine use is linked to decision-making deficits. Therefore, we investigated whether recreational and dependent cocaine users exhibit alterations in social and non-social decision-making. Method The performance of healthy controls (n = 68), recreational cocaine users (n = 68) and dependent cocaine users (n = 30) in classical decision-making paradigms (Iowa Gambling Task, Delay Discounting) and in social interaction paradigms (Distribution Game, Dictator Game) was assessed. Decisions in the social interaction tasks of both cocaine user groups were more self-serving compared with controls as cocaine users preferred higher monetary payoffs for themselves. In the Iowa Gambling Task, only dependent cocaine users were more likely to choose disadvantageous card decks, reflecting worse decision-making. They were also more likely to choose immediate smaller rewards over larger delayed rewards in the Delay Discounting task. Our results imply that both recreational and dependent cocaine users are more concerned with their own monetary gain when interacting with another person. Furthermore, primarily dependent cocaine users are less foresighted and more impulsive regarding immediate reward. Overall, social interaction deficits are already present in recreational users, while non-social decision-making deficits occur predominantly in dependent cocaine users. Thus, social interaction training and cognitive remediation strategies may improve treatment success and quality of life in cocaine dependence.
    Psychological Medicine 07/2013; · 5.59 Impact Factor

Full-text

View
20 Downloads
Available from
Jun 17, 2013