Updated 04 July 2014

Psychostimulants linked to ADHD

The rate of attention deficit hyperactivity disorder (ADHD) among illicit users of psychostimulants is roughly nine times higher than normal, a new study estimates.

The rate of attention deficit hyperactivity disorder (ADHD) among illicit users of psychostimulants is roughly nine times higher than normal, a new study estimates.

Almost half of illicit psychostimulant users showed evidence of ADHD, compared to an estimated rate of no more than 6% in adults in general, the Australian researchers found.

Dr. Sharlene Kaye, who led the study, told Reuters Health by email that the findings "highlight the need for clinicians treating people with substance use disorders to consider, and ideally screen for, ADHD as a potentially comorbid condition that, unidentified and untreated, can worsen treatment response and prognosis for recovery."

In a December online paper in Addiction, Dr. Kaye and colleagues at the University of New South Wales, Sydney note that ADHD is a significant risk factor for the development of alcohol and illicit drug use disorders in adolescence and adulthood and is consistently over-represented among substance use disorder populations.

Estimates suggest it may affect up to 10% of children and 23% of those engaged in substance misuse.

How the study was done

To investigate further, the researcher studied 269 regular users of methamphetamine or cocaine or both. All had used illicit psychostimulants at least weekly for 12 months.

In fact, 71% had used them more than three times per week over this period, and 88% met criteria for psychostimulant dependence.

Their age ranged from 19 to 62 years, with an average of 35.6. Most (86%) had been treated for substance dependence. Half (52%) were in treatment at the time of the interview and most (88%) were unemployed.

In all, 45% screened positive for adult ADHD. Symptoms of inattention (90%) were more prevalent than those of hyperactivity/impulsivity (57%). Only 17% had received a prior diagnosis of ADHD, and 14% were subsequently treated for it.

This, say the investigators, "may in part, reflect the fact that the sample was aged in their mid-thirties, and the level of awareness and diagnosis of ADHD in their childhood years was far lower than it is today."

The findings

Of the positive group, 88% reported that their symptoms were unrelated to drug use and were consistent with their usual behaviour.

After controlling for other factors, ADHD was independently associated with fewer years of education, earlier initiation of regular tobacco use and more extensive lifetime polydrug use.

Only one patient was currently being treated for ADHD with a stimulant medication. The investigators observe that although the first line of treatment is usually stimulant medication such as methylphenidate, these may be contraindicated among substance abusers and extended-release formulations or nonstimulant medications may be more appropriate.

"Identification of comorbid ADHD," the researchers point out "may assist in planning appropriate forms of substance abuse treatment that will reduce the risk of noncompliance with treatment regimens and protocols due to symptoms such as inattention, impulsivity and disorganization."

Overall, they conclude that recognizing the high risk of ADHD in patients seeking drug abuse treatment is important because left undiagnosed and untreated, ADHD may have an impact on "treatment compliance, retention and outcome."

(David Douglas, Reuters Health, December 2012)

Read more:

ADHD causes lifelong problems

Smoking linked to ADHD



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Dr Renata Schoeman has been in full-time private practice as a general psychiatrist (child, adolescent and adult psychiatry) since 2008, currently based in Oude Westhof (Bellville). Renata also holds appointments as senior lecturer in Leadership (USB) and as a virtual faculty member of USB Executive Development’s Neuroleadership programme. She serves on the advisory boards of various pharmaceutical companies, as a director of the Psychiatric Management Group (PsychMG) and is the co-convenor of the South African Society of Psychiatrist (SASOP) special interest group for adult ADHD, and co-founder of the Goldilocks and The Bear Foundation ( She is passionate about corporate mental health awareness and uses her neuroscience background to assist leaders in equipping them to become balanced, healthy and dynamic leaders that take their own and their team’s emotional, intellectual, social health and physical needs into account. Renata is academically active and enjoys research and collaborative work, has published in many peer-reviewed journals, and has presented at local and international congresses. She is regularly invited to present at conferences and to engage with the media. During her post-graduate studies, she trained at Harvard, Boston in neurocognition and neuroimaging. Her awards include, amongst others, the Young Minds in Psychiatry award from the American Psychiatric Association, the Discovery Foundation Fellowship award, a Thuthuka award from the NRF, and a MRC Fellowship. She also received the Top MBA student award and the Director’s award from USB for 2015. She was a finalist for the Businesswomen’s Association of South Africa’s Businesswoman of the Year Award for 2016, and received the Excellence in Media Work award from SASOP during 2016.

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