Pharmacotherapy treatment

There has been substantially more research conducted to examine the efficacy of pharmacological interventions for comorbid ADHD and AOD use disorders, either as stand-alone treatments, or in combination with psychological approaches [503]. Table 31 lists some of the pharmacological treatments for ADHD.

In general, pharmacotherapy for ADHD has been found to be effective in AOD clients but the response is more modest than those with single disorder ADHD [504]. In ADHD as a single disorder, the first line of pharmacotherapy is psychostimulants; methylphenidate first line followed by dexamphetamine if methylphenidate is ineffective [505]. Although psychostimulants are recommended as first line pharmacotherapies for ADHD, it is essential that a medical assessment be conducted prior to prescribing to ensure that the client does not have cardiovascular or other conditions that may contraindicate psychostimulant prescription. Atomoxetine, a noradrenaline reuptake inhibitor, is recommended for individuals who cannot take psychostimulants [7, 506, 507].

For a full list of generic brands available, see the Therapeutic Goods Administration website (https://www.tga.gov.au/).

Although evidence supports the pharmacological treatment of those with comorbid ADHD and AOD use, there has been contention about whether psychostimulants should be used among people with AOD use disorder, due to their potential for misuse [508], leading some treatment guidelines to recommend that non-stimulants be used as the first-line pharmacotherapy treatment for people with comorbid ADHD and AOD use, despite limited evidence of their efficacy [505]. However, in view of the fact that non-stimulants are less efficacious than stimulants in treating ADHD, and in the absence of evidence of any misuse of long-acting stimulants in clinical trials, there is a need to balance the potential risk of misuse and diversion, against the risk of untreated or inadequately treated ADHD [504].

Several RCTs have examined the safety and efficacy of psychostimulant treatment among people with comorbid ADHD and AOD use disorders [509-513]. A systematic review examining psychological and pharmacological interventions for people with comorbid ADHD and AOD use found that despite variation between studies, the evidence largely supports the use of methylphenidate, with the majority of studies finding significant reductions in ADHD symptoms following treatment [478]. AOD use either significantly reduced or remained unchanged, with no studies finding any worsening of symptoms [478, 479]. Of note, studies that reported AOD use reduction also included some form of psychotherapy as an adjunctive therapy (e.g., relapse prevention, group or individual counselling, CBT) , and no cases of medication misuse or abuse were reported [477-479].

Lisdexamfetamine, another type of psychostimulant, was recently listed on the harmaceutical Benefits Scheme for the treatment of ADHD in Australia. One pilot RCT has examined the efficacy of lisdexamfetamine as an adjunctive treatment to NRT, to facilitate smoking cessation among adults with ADHD [514]. There were no differences in smoking outcomes for lisdexamfetamine relative to placebo; however, significantly better outcomes for clinician-rated and self-rated ADHD symptoms were found, suggesting that lisdexamfetamine might be a promising psychostimulant treatment for this comorbid group, pending further and more conclusive evidence.

The use of atomoxetine, a non-stimulant medication for the treatment of comorbid ADHD and AOD use, has been examined in several RCTs [477, 478]. While atomoxetine has demonstrated efficacy relative to placebo for ADHD symptoms, studies report minimal effects for AOD outcomes [477, 478]. Notably, most studies had also included different psychological interventions which were targeted towards reducing AOD use.