Keywords: ADHD, NICE, Psychiatric Comorbidities, Psychoeducation, Methylphenidate, Psychotherapy.
Abstract: ADHD in adults is now recognized as a persistent neurodevelopmental disorder associated with functional impairment, a high frequency of psychiatric comorbidities, and significant individual and social costs. In Italy, however, the availability of services dedicated to adulthood remains heterogeneous and not yet uniformly distributed across the territory, although in recent years increasing clinical, organizational, and regulatory attention has emerged. This paper proposes a synthesis of the current state of the art regarding adult ADHD, with particular reference to the Italian context, focusing on three areas: national epidemiological distribution, the main comorbidities — with a specific focus on substance use disorders, other psychiatric disorders, and personality disorders — and, finally, a public, multidisciplinary, and integrated territorial intervention model, formulated in a general and transferable way for other contexts. NICE guidelines and the most recent European documents converge on the need for a multimodal approach, including specialist assessment, pharmacological treatment when indicated, psychoeducation, structured psychotherapy, and coordination with the service network. The Italian framework is also evolving: since October 19, 2023, methylphenidate has become reimbursable through the National Health Service (SSN) for ADHD in newly diagnosed adults, marking a significant step toward greater structuring of care pathways.
Introduction: ADHD in Adulthood
For a long time, ADHD was considered almost exclusively a childhood disorder. Current evidence instead describes a life-span condition in which a substantial proportion of individuals diagnosed in childhood continue to present clinically significant symptoms and functional impairment during adolescence, young adulthood, and full adulthood. In adults, symptom presentation tends to change: motor hyperactivity is more often expressed as inner restlessness, subjective tension, intolerance to boredom, and a need for constant activation; impulsivity takes the form of hasty decisions, difficulties in behavioral inhibition, and poor emotional modulation; inattentiveness manifests as disorganization, procrastination, attentional dispersion, and difficulties in planning and time management.
The clinical relevance of adult ADHD depends not only on its core symptoms, but above all on their interference with overall functioning: education, employment, household management, romantic relationships, parenting, affect regulation, driving, treatment adherence, and life stability. Added to this is the high burden of psychiatric comorbidities, which can mask the underlying condition, delay diagnosis, and contribute to chronicity. Recent literature highlights that adult ADHD remains underrecognized, underestimated, and undertreated in many European countries; the European ADHD Consensus therefore emphasizes the need for greater professional training, reliable diagnostic procedures, and evidence-based treatments across the entire lifespan.
Distribution of Adult ADHD in Italy: Estimated Prevalence
The epidemiological figure most frequently cited for the general adult population places ADHD prevalence at around 2.8%, with an international range varying approximately between 1.4% and 3.6% depending on the criteria adopted. In the Italian context, the work of Conca and colleagues explicitly reports a prevalence of 2.8% in the general adult population, while also emphasizing that this estimate is likely conservative, since adult ADHD is often underdiagnosed or misdiagnosed.
This figure must be interpreted in light of at least three considerations. The first is methodological: rates vary depending on the tools used, diagnostic criteria, the distinction between full persistence and symptomatic persistence, and the recruitment setting. The second is clinical-organizational: the prevalence “observed” by services often reflects more the system’s ability to identify need than the actual spread of the disorder. The third specifically concerns Italy: the historical scarcity of adult-oriented pathways has likely contributed to a significant amount of undetected cases.
Distribution within Services and Underrecognition
Within the Italian landscape, the distribution of care for adult ADHD has been described as uneven, with an insufficient number of specialized services and territorial coverage far lower than that available for developmental age. A study on diagnostic and therapeutic pathways in Italian services highlighted deficiencies in service provision, marked regional differences, and limited accessibility, with the result that many adult patients experience difficulties both in obtaining an accurate diagnosis and in accessing structured treatments.
The issue of transition from child neuropsychiatry services to adult services also appears central. Recent Italian studies on the topic show that transition protocols are still numerically limited and heterogeneous; this creates interruptions in care during a critical developmental phase, precisely when treatment needs tend to change form and become intertwined with autonomy, university studies, employment, substance use, and affective relationships.
The Recent Change in the Italian Prescriptive Framework
A very important turning point for the Italian context was the update of AIFA regulations: since October 19, 2023, Medikinet (methylphenidate) has become reimbursable through the National Health Service for ADHD in newly diagnosed adults, with management through an AIFA web-based therapeutic plan and authorized centers. This represented a significant step toward the normalization of adult ADHD treatment within the National Health Service.
Comorbidity in Adult ADHD
Comorbidity constitutes one of the most clinically relevant aspects of adult ADHD. Recent reviews and consensus literature converge in considering the presence of concomitant disorders not as the exception, but as the rule, with implications for differential diagnosis, course, suicide risk, quality of life, and treatment response. Literature frequently reports that a large proportion of adults with ADHD present at least one associated psychiatric disorder.
ADHD and Mood and Anxiety Disorders
Among the most frequent comorbidities are depressive disorders, anxiety disorders, and, in a clinically significant proportion, bipolar disorder. The greatest practical issue is that symptoms such as restlessness, affective lability, concentration difficulties, insomnia, or impulsivity may be attributed exclusively to anxiety-depressive or bipolar conditions, leading to failure to recognize the underlying disorder. Recent reviews emphasize that ADHD and anxiety-depressive disorders partially share vulnerabilities, maintenance mechanisms, and functional consequences, and that co-occurrence increases clinical burden and makes therapeutic planning less straightforward.
From a clinical perspective, this means that in public service practice ADHD should be actively investigated especially in patients with early onset of distress, chronic trajectories, partial inefficacy of standard treatments, marked executive disorganization, and a compatible developmental history. Differential diagnosis therefore cannot be reduced to a list of current symptoms, but requires longitudinal anamnesis and attention to functioning.
ADHD and Substance Use Disorders
The association between ADHD and substance use disorders is among the most documented and clinically challenging. Recent systematic reviews and clinical practice synthesis documents confirm that ADHD in adults is associated with an increased risk of early substance use initiation, escalation toward problematic use, and greater clinical severity of addiction.
In the Italian context, a study on adult patients with chronic substance abuse attending psychiatric services identified ADHD-compatible symptoms in 46% of subjects assessed with the DIVA 2.0. Although the data derive from a selected clinical population and are not generalizable to the general population, they strongly indicate the need for systematic screening within addiction and dual diagnosis settings.
More recently, a 2024 study confirmed that patients with ADHD + SUD (substance use disorder) present an overall more severe clinical picture compared to patients with ADHD without SUD, and that certain temperamental dimensions, such as irritability, may help identify subjects at higher risk for substance-related problems. From an organizational perspective, this reinforces the idea that adult ADHD services and addiction services should work in stable integration rather than on separate tracks.
ADHD and Personality Disorders
The relationship between adult ADHD and personality disorders is also highly relevant, particularly with clusters characterized by impulsivity, emotional dysregulation, relational instability, and difficulties in behavioral control. Recent literature shows that co-occurrence is high and that the phenomenological boundary, especially with borderline personality disorder, can be complex. A 2026 meta-analysis reports that more than half of adults with ADHD meet criteria for at least one personality disorder, with greater frequency of borderline, avoidant, depressive, and antisocial profiles; however, this figure should be interpreted cautiously because it derives from heterogeneous samples and not always uniform diagnostic criteria.
Clinically, the issue is not only distinguishing ADHD from personality disorders, but recognizing when they coexist. The presence of a personality disorder may affect adherence, stability of therapeutic alliances, risk management, rejection sensitivity, emotional regulation, and the ability to effectively use standardized interventions. For this reason, in public services, personality assessment should become part of case formulation and the definition of treatment intensity.
Diagnosis and Treatment: The Current State of the Art
NICE guidelines, still considered an international reference and reviewed in 2025 without substantial changes to practice, reiterate that ADHD management should include recognition, accurate diagnosis, pharmacological treatment when indicated, psychoeducational interventions, and multidisciplinary support across the continuum of care.
The updated European ADHD Consensus also emphasizes that diagnosis in adults should be carried out by experienced clinicians, with a multidisciplinary approach and the use of validated tools supporting clinical judgment. In practical terms, this implies at least: accurate anamnesis with attention to developmental history, investigation of current impairments, reconstruction of childhood symptoms, assessment of comorbidities, possible use of structured or semi-structured interviews specific for adults, and neuropsychological assessment when clinically useful.
Regarding treatment, the currently shared framework is multimodal. Medication does not exhaust treatment but, in appropriate cases, may represent an essential component; alongside this, psychoeducation adapted to ADHD, interventions targeting daily functioning, and coordination with general practitioners and territorial services remain decisive for stable outcomes. Recent Italian data show that precisely the psychological and multimodal component has historically been less available within services, making the construction of integrated organizational models even more relevant.
Proposal for an “Italian-Style” Public Territorial Model
In the Italian context, an effective model for the management of adult ADHD should be stably located within the Department of Mental Health, in close connection with territorial services, general practitioners, addiction services, possible young adult pathways, and hospital units involved in the management of comorbidities. Such a model responds to three needs: increasing case identification; making diagnosis appropriate and homogeneous; and offering sustainable multimodal treatments within the National Health Service. Italian literature on care pathways and recent regional organizational documents clearly support the need for adult reference centers with specialist expertise, defined access criteria, and networking capacity.
Access and Referral
Access may occur through the general practitioner, other specialists, addiction services, psychiatric consultation, or referral from developmental-age transition pathways. It is important that the access system not be constructed as a closed hyperspecialist niche, but rather as a specialist function clearly integrated within the territorial network. From this perspective, the adult ADHD center should not “replace” territorial services, but act as a device for assessment, formulation, therapeutic initiation, and ongoing consultation on complex cases.
Multidisciplinary Diagnostic Assessment
Assessment should be structured on multiple levels. A first-level clinical screening allows identification of suspected cases and orientation of priorities. A second specialist level includes psychiatric interview, psychological interview, extended anamnesis, assessment of comorbidities, and use of specific tools for adult ADHD, including when appropriate a structured or semi-structured interview such as the DIVA. A third level, reserved for cases in which clarification of the functional profile or differential diagnosis is necessary, may include neuropsychological assessment of executive functions, sustained attention, working memory, and inhibitory control. Literature and consensus documents insist that tests alone do not establish diagnosis, but may strengthen clinical formulation.
Personalized Therapeutic Plan
Once diagnosis is confirmed, treatment should be personalized according to severity, comorbidities, level of functioning, clinical risk, and shared goals. In the proposed territorial model, the therapeutic plan includes four axes:
First axis: specialist pharmacological treatment. When indicated, the center initiates and monitors pharmacological therapy according to current regulations, including titration, efficacy monitoring, side effect control, and periodic reassessment. Following recent regulatory changes, the SSN now has a more defined framework at least for methylphenidate in newly diagnosed adults.
Second axis: psychoeducation and post-diagnostic support. Psychoeducation is essential for improving insight, adherence, self-observation of symptoms, environmental management, and stigma reduction.
Third axis: psychotherapy and functional interventions. In adult patients, ADHD-adapted psychotherapy remains the most widely shared reference for working on organization, time management, procrastination, emotional dysregulation, and coping. In cases involving personality comorbidity, trauma, addiction, or significant relational instability, psychological treatment should be modulated and often integrated with more intensive or gradual interventions.
Fourth axis: network integration. The frequent presence of depression, anxiety, bipolar disorder, SUD, and personality disorders makes shared coordination with Community Mental Health Centers (CSM), addiction services (SerD), clinical psychology services, general practice, and, for young adults, transition services indispensable. This is the true core of the “Italian-style” model: not an isolated outpatient clinic, but a specialist node capable of operating throughout the territorial network.
Service Organization
From an organizational perspective, the model may be described as a territorial specialist outpatient clinic for adult ADHD embedded within the Department of Mental Health and equipped with:
A multiprofessional team composed of psychiatrist, psychologist, nurse, and psychiatric rehabilitation technician, with access to neuropsychological consultation;
Clear referral criteria;
A dedicated agenda for diagnostic assessment;
Specific pharmacological follow-up pathways;
Spaces for individual or group psychoeducation;
Structured collaboration channels with SerD, general practitioners, and young adult services;
Possibility of clinical supervision for cases with high comorbidity;
This structure is consistent with findings from Italian studies on services and with the most recent organizational documents, which emphasize both the need for reference centers and integration with the territorial network.
Strengths of the Model
A model structured in this way makes it possible to reduce diagnostic delays, improve prescribing appropriateness, increase adherence, limit fragmentation of interventions, and build more coherent pathways for patients with dual or triple comorbidity. Furthermore, it allows a shift in clinical culture from mere “symptom control” toward management centered on functioning and quality of life. This perspective is particularly important within the SSN, where sustainability depends less on isolated technological sophistication and more on the quality of connections between services.
Conclusions
The current state of the art on adult ADHD shows that the issue is no longer whether the disorder exists in adulthood, but how to make recognition more timely and treatment more effective within real-world care settings. In Italy, the epidemiological figure of approximately 2.8% in the general adult population suggests that the number of individuals potentially requiring assessment and treatment is high, while the availability of specialized services has so far remained limited and irregular.
The most complex clinical issue remains comorbidity. In public services, adult ADHD frequently coexists with depression, anxiety, bipolar disorder, addictions, emotional dysregulation, and personality disorders. Under such conditions, diagnosis requires time, longitudinal expertise, and case formulation skills. It follows that the most useful model is not one centered on a single technique, but rather one integrating different competencies within a graduated and territorially connected pathway.
Adult ADHD today represents an emerging priority for Italian public mental health. Scientific knowledge is sufficiently robust to affirm that it is a frequent, clinically significant, and treatable condition. Nevertheless, organizational criticalities remain: underdiagnosis, uneven access, lack of transition pathways, and limited dissemination of truly multimodal models. The recent expansion of prescribing possibilities within the National Health Service constitutes an important step forward, but in order to produce real impact it must be accompanied by territorial specialist services, clinical training, and integration with psychological and addiction treatment networks. An “Italian-style” public territorial model, multidisciplinary and connected to mental health services, currently appears to be the solution most consistent with the clinical needs of adult patients and with the architecture of the Italian National Health Service.
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