Archive for July, 2013

Impulsive adolescents more likely to drink heavily

Scientists at the University of Liverpool have shown that young people who show impulsive tendencies are more prone to drinking heavily at an early age.

The research suggests that targeting personality traits, such as impulsivity, could potentially be a successful intervention in preventing adolescent drinking from developing into problems with alcohol in later life.

Studies in the UK show that approximately 24% of 12 year olds have reported at least one episode of alcohol consumption, rising to 77% of 15 year olds.

Impulsive Behavior Linked to Drinking

Previous research has suggested that impulsive behavior is linked with adolescent drinking, but it is unclear whether young people who are impulsive tend to drink more, or whether drinking whilst the brain is still developing is particularly harmful and can lead to the progression of impulsive behaviors.

The team used computer tests that measured inhibitory control, the ability to delay gratification, and risk-taking. More than 280 young people who were aged 12 or 13 at the beginning of the study took part in the study. The participants repeated the computer tests every six months over the two years of the study.

Alcohol Doesn’t Increase Impulsivity

Results showed that those participants who were more impulsive in the tests went on to drink more heavily or have problems with alcohol at a later time. The study did not, however, show that alcohol consumption led to increased impulsive behaviour on the computer tests. This suggests that there is a link between impulsivity and adolescent drinking, but that alcohol may not necessarily lead to increased impulsive behaviour in the short-term.

Professor Matt Field, from the University’s Institute of Psychology Health and Society, explains: “Young people in the UK are starting to drink alcohol at a younger age than in the past, and much of this reflects broad social trends. There are, however, significant differences in the age at which teenagers start to experiment with alcohol and the age at which they start drinking regularly.

Targeting Prevention Programs

“It is important to identify the psychological characteristics of adolescents who are likely to go on to drink heavily, because this can help us target alcohol prevention more effectively. In addition, we need to identify the consequences of heavy drinking during adolescence for health in general, and brain development in particular.

“Our results show that more impulsive individuals are more likely to start drinking heavily in the future compared to less impulsive individuals. The next steps are to take these results and apply them to prevention interventions that are tailored to individual characteristics, such as impulsivity.

“We also need to conduct studies where we follow-up young people for longer than the two years that we did in the present study. This will help us to understand whether heavy drinking over a longer period during adolescence has an impact on impulsive behaviour.”

July 4th, 2013  in Alcohol No Comments »

Why Some Pot Smokers Are Slackers

Researchers found that dopamine levels in a part of the brain called the striatum were lower in people who smoke more cannabis and those who began taking the drug at a younger age.
They suggest this finding could explain why some cannabis users appear to lack motivation to work or pursue their normal interests.
The study, by scientists at Imperial College London, UCL and King’s College London, was funded by the Medical Research Council and published in the journal Biological Psychiatry.
The researchers used PET brain imaging to look at dopamine production in the striatum of 19 regular cannabis users and 19 non-users of matching age and sex.
The cannabis users in the study had all experienced psychotic-like symptoms while smoking the drug, such as experiencing strange sensations or having bizarre thoughts like feeling as though they are being threatened by an unknown force.
The researchers expected that dopamine production might be higher in this group, since increased dopamine production has been linked with psychosis. Instead, they found the opposite effect.
The cannabis users in the study had their first experience with the drug between the ages of 12 and 18. There was a trend for lower dopamine levels in those who started earlier, and also in those who smoke more cannabis. The researchers say these findings suggest that cannabis use may be the cause of the difference in dopamine levels.
The lowest dopamine levels were seen in users who meet diagnostic criteria for cannabis abuse or dependence, raising the possibility that this measure could provide a marker of addiction severity.
Previous research has shown that cannabis users have a higher risk of mental illnesses that involve repeated episodes of psychosis, such as schizophrenia.
“It has been assumed that cannabis increases the risk of schizophrenia by inducing the same effects on the dopamine system that we see in schizophrenia, but this hasn’t been studied in active cannabis users until now,” said Dr Michael Bloomfield, from the Institute of Clinical Sciences at Imperial, who led the study.
“The results weren’t what we expected, but they tie in with previous research on addiction, which has found that substance abusers – people who are dependent on cocaine or amphetamine, for example – have altered dopamine systems.
“Although we only looked at cannabis users who have had psychotic-like experiences while using the drug, we think the findings would apply to cannabis users in general, since we didn’t see a stronger effect in the subjects who have more psychotic-like symptoms. This needs to be tested though.
“It could also explain the ‘amotivational syndrome’ which has been described in cannabis users, but whether such a syndrome exists is controversial.”
Other studies have looked at dopamine release in former cannabis users and not seen differences with people who haven’t taken cannabis, suggesting that the effects seen in this study are likely to be reversible.

Researchers found that dopamine levels in a part of the brain called the striatum were lower in people who smoke more cannabis and those who began taking the drug at a younger age.

They suggest this finding could explain why some cannabis users appear to lack motivation to work or pursue their normal interests.

The study, by scientists at Imperial College London, UCL and King’s College London, was funded by the Medical Research Council and published in the journal Biological Psychiatry.

Lack of Dopamine Production

The researchers used PET brain imaging to look at dopamine production in the striatum of 19 regular cannabis users and 19 non-users of matching age and sex.

The cannabis users in the study had all experienced psychotic-like symptoms while smoking the drug, such as experiencing strange sensations or having bizarre thoughts like feeling as though they are being threatened by an unknown force.

The researchers expected that dopamine production might be higher in this group, since increased dopamine production has been linked with psychosis. Instead, they found the opposite effect.

Smokers Started Early

The cannabis users in the study had their first experience with the drug between the ages of 12 and 18. There was a trend for lower dopamine levels in those who started earlier, and also in those who smoke more cannabis. The researchers say these findings suggest that cannabis use may be the cause of the difference in dopamine levels.

The lowest dopamine levels were seen in users who meet diagnostic criteria for cannabis abuse or dependence, raising the possibility that this measure could provide a marker of addiction severity.

Previous research has shown that cannabis users have a higher risk of mental illnesses that involve repeated episodes of psychosis, such as schizophrenia.

Results Not Expected

“It has been assumed that cannabis increases the risk of schizophrenia by inducing the same effects on the dopamine system that we see in schizophrenia, but this hasn’t been studied in active cannabis users until now,” said Dr Michael Bloomfield, from the Institute of Clinical Sciences at Imperial, who led the study.

“The results weren’t what we expected, but they tie in with previous research on addiction, which has found that substance abusers – people who are dependent on cocaine or amphetamine, for example – have altered dopamine systems.

“Although we only looked at cannabis users who have had psychotic-like experiences while using the drug, we think the findings would apply to cannabis users in general, since we didn’t see a stronger effect in the subjects who have more psychotic-like symptoms. This needs to be tested though.

Amotivational Syndrome

“It could also explain the ‘amotivational syndrome’ which has been described in cannabis users, but whether such a syndrome exists is controversial.”

Other studies have looked at dopamine release in former cannabis users and not seen differences with people who haven’t taken cannabis, suggesting that the effects seen in this study are likely to be reversible.

July 4th, 2013  in Illegal Drugs 1 Comment »