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Autumn 2010, Volume 14, No 1

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Research Update

 

By Mark de la Hey

 

Dissociation common among people with substance use disorders

Researchers at the University of Hamburg in Germany have found high rates of dissociation in people with substance use problems, notably among those with both alcohol and drug dependence. However, these associations appear to be the result of the underlying characteristics of individuals with substance use problems, rather than the substance use itself. The study involved 459 individuals, 182 of whom were alcohol dependent, 154 were drug dependent, and 123 were dependent on both alcohol and drugs. Participants completed questionnaires to confirm alcohol and drug dependence and measure rates of childhood trauma, post-traumatic stress disorder (PTSD) and dissociation. The results showed high rates of traumatic childhood events in all three groups. Higher levels of dissociation were found in individuals with drug dependence and in those with both drug and alcohol dependence compared with those who were alcohol dependent alone. Female participants with either drug dependence or both drug and alcohol dependence were most likely to meet criteria for a dissociative disorder. A low proportion of men in the study and of women with alcohol dependence alone met these criteria. However, when childhood trauma, PTSD, age and gender were taken into account, the influence of any type of substance use problem was not significant. Rather, it was the severity of childhood traumatic experiences, especially emotional abuse, that was most strongly associated with dissociation. Higher rates of dissociation were also evident among younger participants. The authors conclude that screening for dissociation should focus not just on identifying substance use problems, but should also consider female gender, younger age and especially a history of childhood trauma.

Drug and Alcohol Dependence, June 1, 2010, v. 109 (1–3): 84–89. Ingo Schäfer et al., Center for Interdisciplinary Addiction Research, University of Hamburg, Hamburg, Germany.

 

Injectable heroin effective treatment for heroin addiction

Injectable heroin can be more effective than methadone in treating heroin addiction, according to a new study from King’s College London. The study involved 127 individuals with chronic heroin addiction who were being treated with oral methadone but who continued regularly to inject with street heroin. Participants were assigned to receive injectable heroin, injectable methadone or optimized oral methadone. After six months, 88 per cent of those given injectable heroin remained in treatment, compared with 81 per cent of those given injectable methadone and 69 per cent of those on oral methadone. The primary outcome objective was a result of at least 50 per cent negative urine samples for street heroin during the last three months of the study. This outcome was achieved by 72 per cent of those on injectable heroin, compared with 39 per cent of those on injectable methadone and 27 per cent of those on oral methadone. Abstinence from street heroin during the final month of the study was achieved by 37 per cent of those on injectable heroin, 18 per cent of those on injectable methadone and eight per cent of those on oral methadone. The authors note that although the costs of supervised injectable treatment are relatively high, the gains from reduced heroin use are significant given the considerable harm it causes users, their families and society at large.

Lancet, May 29, 2010, v. 375 (9729): 1885–1895. John Strang et al., National Addiction Centre, King’s College London, London, United Kingdom.

 

High rates of PTSD and depression found among Iraq veterans

New research from the Walter Reed Army Institute of Research in Silver Spring, Maryland, indicates that U.S. soldiers returning from combat in Iraq have persistently high rates of post-traumatic stress disorder (PTSD) and depression. The study involved 13,226 U.S. army soldiers from four Active Component and two National Guard brigade combat teams. Researchers collected anonymous mental health surveys from the soldiers three and 12 months after deployment from Iraq. After three months, rates of PTSD with serious functional impairment were eight per cent among Active Component soldiers and seven per cent among National Guard soldiers. At 12 months, rates had risen to nine per cent for Active Component and 12 per cent for National Guard soldiers. Rates for depression with serious functional impairment at three months were eight per cent for Active Component soldiers and five per cent for National Guard soldiers. At 12 months, these rates had risen to nine per cent for Active Component and seven per cent for National Guard soldiers. The fact that rates of PTSD and depression increased between the three-month and 12-month surveys led the authors to conclude that the 12 to 18 months typically given to Active Component soldiers between deployments may not be sufficient to allow them to recover.

Archives of General Psychiatry, June 2010, v. 67 (6): 614–623. Jeffrey L. Thomas et al., Department of Military Psychiatry, Walter Reed Army Institute of Research, Silver Spring, Maryland.

 

Young smokers often unaware of emerging signs of addiction

Youth who smoke occasionally exhibit clear symptoms of nicotine dependence, but often don’t recognize those symptoms as precursors of addiction, concludes a study from the University of Massachusetts Medical School in Worcester. Researchers looked at data on 370 adolescents from a four-year study of nicotine dependence. Sixty-two per cent of the youth, aged 11 to 13 when the study began, smoked at least once a month, with 25 per cent smoking daily. Thirty-three per cent reported symptoms of dependence, such as cravings, withdrawal symptoms, feelings of addiction or difficulty controlling cigarette use. The more frequently participants smoked, the more dependence symptoms they reported. Forty per cent of those who smoked cigarettes at least once a month escalated to daily smoking, and the presence of any dependence symptom increased the risk that the participant would progress to daily smoking. Participants typically experienced cravings and symptoms of nicotine withdrawal before they began smoking daily. Feelings of addiction and difficulty controlling tobacco use emerged after the onset of daily smoking. The authors suggest that this pattern indicates that non-daily smoking results in nicotine dependence, which leads to increased smoking frequency. This in turn leads to additional symptoms of dependence, creating a positive feedback loop that leads to further increases in smoking frequency. Young people tend not to realize that cravings and withdrawal are symptoms of addiction, leading the authors to recommend research to determine whether educating young people to recognize early symptoms of dependence could lead to more successful smoking cessation efforts.

Pediatrics, June 2010, v. 125 (6): 1127–1133. Chyke A. Doubeni et al., Department of Family Medicine and Community Health, University of Massachusetts Medical School, Worcester, Massachusetts.

 

Near-win situations may encourage problem gamblers to gamble more

Among regular gamblers, a near-win stimulates parts of the brain associated with reward, which may lead them to gamble even more, according to research from the University of Nottingham in England. Researchers recruited 20 regular gamblers whose gambling ranged from recreational playing to probable pathological gambling. Functional MRI scans were performed on participants while they played a slot machine simulation. Two slot machine reels were presented on a computer screen and participants were asked to choose an icon from the left reel. The right reel was then spun and if it stopped on the selected icon the participant was given a small monetary reward. Participants exhibited significant responses in the ventral striatum region of the brain after both wins and after near-misses, in which the slot machine reel stopped one position above or below the selected icon. There was also a positive relationship between gambling severity and dopamine response in the midbrain to near-miss outcomes – the more severe an individual’s gambling was the greater the response. There was no such relationship in response to win outcomes. These results suggest that near-misses enhance dopamine transmission in problem gamblers, which could explain why near-misses drive them to gamble more. The researchers state that this points to neurobiological similarities between problem gambling and drug addiction, which also involves enhanced dopamine transmission. The responses to near-win outcomes may help to explain the cognitive distortions that lead problem gamblers to overestimate their chances of winning in the future. The researchers suggest that in future, drugs which reduce dopamine transmission may be useful in reducing these cognitive distortions.

Journal of Neuroscience, May 5, 2010, v. 30 (18): 6180–6187. Henry W. Chase and Luke Clark, School of Psychology, University of Nottingham, Nottingham, United Kingdom.

 

Thrill of risky behaviour trumps concern over consequences among adolescents

New research from University College London indicates that adolescents’ tendency to engage in risky behaviour is due not to difficulty estimating negative consequences of their behaviour, but to the fact that the thrill adolescents experience in risky situations outweighs their concern about negative consequences. Researchers recruited 89 male participants: 20 pre-adolescents aged 9–11, 26 young adolescents aged 12–15, 26 mid-adolescents aged 15–18, and 17 adults aged 25–35. Participants played one of two “wheel of fortune” games on a computer and indicated their emotional responses after each trial. The researchers found that the ability to weigh expected value (the value of potential outcomes weighted by the probability of their occurrence) increased with age. Older participants showed a preference for gambles with a higher expected value. On the other hand, a preference for risky gambles (gambles with greater variance in outcome) peaked at age 14 and declined thereafter. Compared with pre-adolescents, young adolescents showed a significant increase in expressions of relief or regret when shown that the outcome would have been worse or better had they chosen to play the other game on the screen. These emotions decreased gradually through mid-adolescence and adulthood. The researchers suggest that adolescents’ preference for risky gambles appears to have been largely driven by their strong enjoyment at winning in “lucky escape” situations, where the outcome could have been much worse had they chosen the other wheel. While these results shed light on the reasons for adolescent risk-taking, the authors caution that risk-taking in real-life situations is likely to have various underlying causes.

Cognitive Development, April–June 2010, v. 25 (2): 183–196. Stephanie Burnett et al., University College London Institute of Cognitive Neuroscience, London, United Kingdom.

 

Telephone therapy may ease depression

Telephone psychotherapy can be almost as effective in treating depression as face-to-face psychotherapy, according to new research from Brigham Young University in Provo, Utah. The six-month study followed 30 adults seeking treatment for depression at an outpatient mental health clinic. Treatment involved cognitive-behavioural therapy delivered over the phone in eight weekly half-hour sessions, followed by two monthly half-hour booster sessions. All participants completed the three-month follow-up assessment, and 87 per cent completed the six-month follow-up assessment. All participants completed at least on telephone session, while 90 per cent completed at least four and 77 per cent completed at least eight sessions. At the six-month follow-up, 69 per cent of participants said they were “very satisfied” with the treatment they received. Forty-two per cent of participants in this study were considered recovered after six months, compared with 50 per cent of participants in a recent study of in-person cognitive-behavioural therapy. The cost of each session of telephone therapy was approximately $40, which compares favourably with a recent estimate of $96 for a typical session of traditional office counselling. Participants in this study indicated that they appreciated the privacy and flexibility of telephone counselling. The study’s authors note that telephone therapy has the advantage of avoiding some of the barriers associated with traditional office psychotherapy, such as stigma, travel, waiting time and costs.

Behavior Therapy, June 2010, v. 41: 229–236. Steve Tutty et al., Brigham Young University, Provo, Utah.