Nav: Home

Cocaine use during adolescence is even more harmful than during adulthood

October 18, 2017

People who begin using cocaine during adolescence display more significant cognitive deficits than people who begin using the drug in adulthood. That which experts in neuroscience have long suspected has been given an objective confirmation by researchers working at the University of São Paulo's Medical School (FM-USP), in Brazil.

When scientists compared the two groups of cocaine users, they observed pronounced differences, mainly in specific neuropsychological functions such as sustained attention (required for performing long tasks, such as completing a questionnaire), working memory (used in specific actions, for example, a waiter remembering the order of each table until the time comes to deliver the orders) and declarative memory (storing and retrieving data after a period of time).

They also found that among early-onset users, the concurrent consumption of cannabis and alcohol was 50% and 30% more frequent, respectively, compared with late-onset users, defined as those who began using cocaine at or over the age of 18. The complete findings of the research project, which was supported by the São Paulo Research Foundation - FAPESP, were published in the journal Addictive Behaviors.

"Adolescence is considered one of the key stages of brain development when surplus synapses are eliminated and the structures essential to adulthood are selected and refined. Drug use in this stage can impair the brain programming process and lead to the loss of important connections," said Paulo Jannuzzi Cunha, a professor at FM-USP and principal investigator for the project.

Differentiated Methodology

According to Cunha, one of the novel aspects of the research project conducted at the Psychiatry Institute of Hospital das Clínicas, FM-USP's teaching and general hospital, was the measurement of cognitive functions during controlled abstinence.

"Many studies of this kind assess outpatients without any possibility of knowing whether they'll use drugs when they go home," he said. "In our case, however, all participants were hospital inpatients. We can, therefore, be sure the findings didn't reflect acute effects of cocaine or other substances."

The sample contained 103 cocaine-dependent patients, 52 of whom were early-onset users who had begun using the drug before they were 18, while 51 were late-onset users who began when they were 18 or older. All individuals were evaluated after at least a week of abstinence. The absence of cocaine metabolites was verified by toxicological urine tests. A third group of 63 people with no history of psychoactive substance use served as the control.

The participants' ages ranged from 20 to 35. The proportions of men and women were similar. One of the early-onset users had begun consuming cocaine at age 12.

"Data in the scientific literature shows that a brain region called the prefrontal cortex continues to develop until age 25. This region relates to what are known as executive functions, such as planning, decision making, inhibitory control, attention, and working memory. We, therefore, decided to investigate whether these functions were more impaired in early-onset users," said psychologist Bruna Mayara Lopes, first author of the article.

The evaluation involved a number of tests, including the Frontal Assessment Battery (FAB), Stroop Color Word Test (SCWT), Controlled Oral Word Association Test (COWAT), Wisconsin Card Sorting Test (WCST), Rey Osterrieth Complex Figure Test (ROCFT) and Iowa Gambling Task (IGT). The use of alcohol and other drugs was assessed using the Addiction Severity Index (ASI-6).

"Basically, we presented the participants with a task they had to complete, such as repeating a sequence of numbers in reverse order or reproducing a figure from memory about 30 minutes after observing it," Lopes said.

When they compared late-onset users with the control group and adjusting the results for variables such as age and intelligence quotient (IQ), the only difference the researchers found was in divided attention, which relates to the ability to perform multiple tasks at the same time.

Going deeper

In a study under way at USP's Neuroimaging Laboratory (LIM-21), the researchers are now seeking to correlate the cognitive profile observed in the two groups of cocaine-dependent patients with decision-making and resting-state brain activity, using functional magnetic resonance imaging (fMRI). Studies of brain structure and correlations with levels of a protein known as BDNF (brain-derived neurotrophic factor) will also be performed using these findings.

"We're measuring such variables as prefrontal cortex volume and white matter integrity. We'll be able to disclose some of our findings shortly," said Priscila Dib Gonçalves, supervisor of the Psychology & Neuropsychology Service at the Psychiatry Institute and co-author of the article.

White matter, found in the deeper tissues of the brain, contains axons connecting grey matter, which is where all synapses are located.

According to Gonçalves, a higher probability of cognitive impairment due to early-onset drug use was already observed in a study involving 104 chronic cannabis users. This study, published in 2011 in the British Journal of Psychiatry, was conducted at the Federal University of São Paulo (UNIFESP) by Maria Alice Fontes. It found that people who began smoking marijuana before age 15 underperformed late-onset users in tests that assessed executive functions.

For Gonçalves, both studies evidence the need to develop more effective prevention strategies and programs targeting adolescents. "We live in a society that associates recreation with the use of psychoactive substances, and this is an important cultural aspect," she said. "One way to raise awareness of the risks could be to hold workshops with students, who should be called on to play a leading role in this awareness-raising process, rather than being passive recipients of information."

For Cunha, the results also show that patients with severe cognitive deficits need intense multidisciplinary treatment, including medication as well as therapy.
-end-
About São Paulo Research Foundation (FAPESP)

The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. For more information: http://www.fapesp.br/en.

Fundação de Amparo à Pesquisa do Estado de São Paulo

Related Memory Articles:

Previously claimed memory boosting font 'Sans Forgetica' does not actually boost memory
It was previously claimed that the font Sans Forgetica could enhance people's memory for information, however researchers from the University of Warwick and the University of Waikato, New Zealand, have found after carrying out numerous experiments that the font does not enhance memory.
Memory boost with just one look
HRL Laboratories, LLC, researchers have published results showing that targeted transcranial electrical stimulation during slow-wave sleep can improve metamemories of specific episodes by 20% after only one viewing of the episode, compared to controls.
VR is not suited to visual memory?!
Toyohashi university of technology researcher and a research team at Tokyo Denki University have found that virtual reality (VR) may interfere with visual memory.
The genetic signature of memory
Despite their importance in memory, the human cortex and subcortex display a distinct collection of 'gene signatures.' The work recently published in eNeuro increases our understanding of how the brain creates memories and identifies potential genes for further investigation.
How long does memory last? For shape memory alloys, the longer the better
Scientists captured live action details of the phase transitions of shape memory alloys, giving them a better idea how to improve their properties for applications.
A NEAT discovery about memory
UAB researchers say over expression of NEAT1, an noncoding RNA, appears to diminish the ability of older brains to form memories.
Molecular memory can be used to increase the memory capacity of hard disks
Researchers at the University of Jyväskylä have taken part in an international British-Finnish-Chinese collaboration where the first molecule capable of remembering the direction of a magnetic above liquid nitrogen temperatures has been prepared and characterized.
Memory transferred between snails
Memories can be transferred between organisms by extracting ribonucleic acid (RNA) from a trained animal and injecting it into an untrained animal, as demonstrated in a study of sea snails published in eNeuro.
An immunological memory in the brain
Inflammatory reactions can change the brain's immune cells in the long term -- meaning that these cells have an 'immunological memory.' This memory may influence the progression of neurological disorders that occur later in life, and is therefore a previously unknown factor that could influence the severity of these diseases.
Anxiety can help your memory
Anxiety can help people to remember things, a study from the University of Waterloo has found.
More Memory News and Memory Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Making Amends
What makes a true apology? What does it mean to make amends for past mistakes? This hour, TED speakers explore how repairing the wrongs of the past is the first step toward healing for the future. Guests include historian and preservationist Brent Leggs, law professor Martha Minow, librarian Dawn Wacek, and playwright V (formerly Eve Ensler).
Now Playing: Science for the People

#566 Is Your Gut Leaking?
This week we're busting the human gut wide open with Dr. Alessio Fasano from the Center for Celiac Research and Treatment at Massachusetts General Hospital. Join host Anika Hazra for our discussion separating fact from fiction on the controversial topic of leaky gut syndrome. We cover everything from what causes a leaky gut to interpreting the results of a gut microbiome test! Related links: Center for Celiac Research and Treatment website and their YouTube channel
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.