Attention Deficit Hyperactivity Disorder (ADHD) and Substance Use Disorders (SUDs) is a highly common comorbid condition associated with serious medical and psychosocial consequences. However, and despite the international consensus recommending integrated treatment for this comorbidity, few studies tested the efficacy of specific psychotherapeutic treatment for this comorbidity.

The aim of this study is to test the efficacy of a specific group Cognitive and Behavioral Therapy (CBT) for the treatment of adults with this comorbidity.

This is a longitudinal, randomized controlled intervention study utilizing a crossover design between the intervention and treatment-as-usual (TAU) waitlist condition, aimed at testing the effectiveness of an integrated psychotherapeutic group treatment for adults with comorbid Attention Deficit Hyperactivity Disorder (ADHD) and Substance Use Disorders (SUDs).

Substance Use Disorders (SUDs) affect between 0.5% and 15% of the general population and are responsible for a huge morbidity, mortality and social costs (Aldridge et al., 2018; Peterson et al., 2021). Among existing psychotherapeutic approaches, Cognitive and Behavioural Therapy (CBT) is one of the most widely validated, particularly in the addictive population (Hampel et al., 2020; Kabisa et al., 2021; Knapp et al., 2021; Marlatt & Donovan, 2005; Ray et al., 2020). Psychiatric comorbidities are very often associated with SUD (Toftdahl et al., 2016). Among these, Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common, occurring in more than 20% of adults with SUDs (Rohner et al., 2023; van Emmerik-van Oortmerssen et al., 2012) compared with 2.6% in the general population (Song et al., 2021).

The diagnosis and management of adult ADHD are difficult (Cortese et al., 2018; Lopez et al., 2018), particularly when ADHD is comorbid with SUD (Fatséas et al., 2016; Icick et al., 2020; Young et al., 2015). No specific treatment has been yet validated for this comorbidity. It is noteworthy that recognition of adult ADHD has grown considerably in France over the last years.

In this field, the international consensus on the screening, diagnosis and management of this comorbidity recommends integrated treatments (targeting the different disorders at the same time), combining pharmacotherapy with psychotherapy, emphasing the relevance of CBT in this field (Crunelle et al., 2018; Özgen et al., 2020). Despite these immense unmet needs, only one specific ADHD-SUDs psychotherapeutic program has been evaluated to date (van Emmerik-van Oortmerssen et al., 2019)

This protocol aims to test the efficacity of an integrated group Cognitive Behavioral Therapy (CBT) treatment for adults with comorbid Attention Deficit Hyperactivity Disorder (ADHD) and Substance Use Disorders (SUDs) on emotional dysregulation at the primary outcome. Addiction and ADHD symptoms, quality of life, self-esteem, and transdiagnostic constructs (impulsivity, perseverative thinking) are considered as secondary outcomes.

This study corresponds to a longitudinal intervention study using a cross-over design between the group intervention and treatment-as-usual (TAU) waiting condition.

Participants corresponding to inclusion criteria and consenting to participate are enrolled to the study and undergo a first interview assessing clinical and sociodemographic variables and self-rated questionnaires for primary and secondary outcomes. Then they are computer-randomised, controlling for duration of pharmacological treatment in two arms: (1) Treatment-Waiting and (2) Waiting-Treatment. In each condition (Waiting or Treatment) participant conserve their usual treatment for SUD and ADHD, excluding psychotherapeutic group interventions.

The first sequence consists in eight weeks of treatment (TAU for the Waiting-Intervention arm, and TAU+integrated group CBT for the Intervention-Waiting arm). The integrated group CBT consists in weekly two hours groups sessions. At the end of the first sequence and before the second sequence, participants undergo again self-report questionnaires for primary and secondary outcomes.

For the second sequence, participants switch the intervention condition for eight weeks (TAU+integrated group CBT for the Waiting-Intervention arm, and TAU for the Intervention-Waiting arm). At the end of this sequence, participants undergo again self-report questionnaires for primary and secondary outcomes, representing (1) post-intervention data for the Waiting-Intervention arm and (2) a two moths follow-up for the Intervention-Waiting arm.

The third sequence (follow-up) consists in three months of TAU condition, without any exclusion criteria for psychotherapeutic group interventions, ending with a last completion of a shortened battery of questionnaires for primary and secondary outcomes (if needed, questionnaires could be assessed by phone).

Inclusion Criteria:

• Age 18 or older ;
• Suffer from at least one moderate to severe SUD regarding the DSM-5 (tobacco excluded) ;
• Being currently treated for a SUD by a physician of a psychologist ;
• Being diagnosed with an ADHD according to the DIVA 2.0 of DIVA-5 ;
• Being affiliated to a health insurance ;
• Understanding and being able to express himselves in French
• Signed consent

Exclusion Criteria:

• Age under 18;
• Pregnant or breastfeeding women;
• Not having sign the consent form;
• Major difficulties in understanding and/or expressing themselves in french;
• Severe cognitive impairment;
• Acute medical condition making assessment impossible and/or contraindicating participation in group intervention;
• Substance use disorder in a protected environment, currentlu or in the last 15 days, or expected during the study;
• No substance use disorder other than tobacco use disorder;
• Persons under guardianship;
• Participant deprived of liberty or under penal care orders;
• Participation in another group psychotherapeutic intervention throughout the duration of the intervention