Healthcare provider perspectives on diagnosing and treating adults with attention-deficit/hyperactivity disorder

ABSTRACT

Objective: This study examined adult attention-deficit/hyperactivity disorder (ADHD) screening and management patterns among healthcare provider (HCP) subgroups.

Methods: An online survey of US-based HCPs (neurologists, n = 200; nurse practitioners [NPs], n = 100; psychiatrists, n = 201; primary care physicians [PCPs], n = 201) was conducted from May to June 2017. The survey assessed issues relating to adult ADHD screening and management and HCP perceptions of factors influencing patient choice of pharmacotherapy. Participants were required to be experienced in diagnosing and/or treating ADHD in adults (≥5 patients/month for neurologists and NPs; ≥10 patients/month for psychiatrists and PCPs).

Results: Significantly greater percentages of psychiatrists than non-psychiatrists were confident in diagnosing ADHD (P < 0.001) and screened/evaluated for ADHD in patients with depression/anxiety disorders (P < 0.001). Significantly greater percentages of psychiatrists versus non-psychiatrists prescribed once-daily long-acting (LA) stimulants (71.6% vs 62.2%; P = 0.023) or short-acting (SA) stimulants more than once daily (40.3% vs 29.7%; P = 0.009) as first-line therapy. In contrast, a significantly greater percentage of non-psychiatrists than psychiatrists prescribed once-daily SA stimulants (32.9% vs 17.4%; P < 0.001). Psychiatrist and non-psychiatrist HCPs viewed insurance coverage/treatment costs (79.9%), perceived duration of effect (72.2%), and side effects (66.5%) as important factors to patients when choosing treatment. HCPs reported that the greatest mean ± SD percentages of patients changed their treatment regimen in the past 6 months because of perceptions of insufficient duration of effect (35.4% ± 22.1%) and lack of efficacy (30.3% ± 21.0%).

Conclusion: Compared with psychiatrists, non-psychiatrists exhibited less confidence in diagnosing adult ADHD and experienced greater difficulty determining optimal treatment regimens.

KEYWORDS:

• Adult
• attention-deficit/hyperactivity disorder
• screening
• diagnosis
• treatment

1. Introduction

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder that can persist into adulthood [1]. Adults with ADHD exhibit increased rates of executive dysfunction and psychiatric comorbidities, as well as poorer educational and occupational outcomes, compared with adults who are not diagnosed with ADHD [2–5]. Although the prevalence of adult ADHD has been estimated to be 4.4% in the United States and 3.4% worldwide [1,6], only a minority of adults with ADHD receive treatment [1]. In a large-scale study based on the National Comorbidity Survey Replication, the 12-month treatment rate for ADHD in adults was 10.9% [1].

Low treatment rates for adult ADHD could be a consequence of the many challenges associated with diagnosing and treating adult ADHD. Although published review articles provide clinical recommendations for managing ADHD in adults [7–9], formal evidence-based guidelines for adults with ADHD from professional associations in the United States have yet to be established, unlike the multiple guidelines that exist for the diagnosis and treatment of ADHD in children and adolescents [10–13]. Based on non-US guidelines from the National Institute for Health and Clinical Excellence (NICE) [12] and the Canadian ADHD Resource Alliance (CADDRA) [11], first-line pharmacotherapy for adults with ADHD should typically consist of an amphetamine-based or methylphenidate-based stimulant. Nonstimulants, atomoxetine or guanfacine, can be used as adjuncts in patients exhibiting partial responses to psychostimulants or as monotherapy in patients who do not tolerate psychostimulant therapy [11]. Consideration should also be given to the presence of comorbidities, with nonstimulants (ie, atomoxetine) being considered when tics, Tourette’s syndrome, anxiety disorders, or risk for psychostimulant misuse are present [12]. Psychotherapy (eg, cognitive behavior therapy) should be considered in adult ADHD patients exhibiting low self-esteem, overwhelming stress, or mood/anxiety disorders [11]. However, in regard to determining optimal treatment strategies, it is important to note that there are no specific algorithms to follow. Rather, treatment should be based on the individual needs of each patient [11].

In addition, many healthcare providers (HCPs) lack confidence in their training or their ability to diagnose and/or treat adult ADHD, despite the fact that the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) clearly specifies criteria for diagnosing ADHD in adults [14]. In a survey of US primary care physicians (PCPs), only 34% of respondents indicated that they were very/extremely knowledgeable about adult ADHD [15]. In a survey of US-based HCPs in the college/university setting, only 32% of nurses reported that they were comfortable/very comfortable in recognizing ADHD symptoms in young adults, and approximately two-thirds of physicians and nurses somewhat or strongly agreed that it was difficult to diagnose ADHD in young adults [16]. HCPs in the United States may also lack confidence in prescribing treatments for adult ADHD because of a lack of experience in managing adult patients with ADHD, the presence of psychiatric comorbidities, and a reluctance to prescribe psychostimulants [17]. Similar findings are reported in studies conducted outside of the United States, with 32% of PCPs in Saudi Arabia having poor knowledge of ADHD [18] and more than 40% of psychiatrists from Turkey agreeing that adult ADHD is difficult to differentiate from other disorders [19]. Lastly, there are also communication gaps among HCPs and between HCPs and their patients. In a survey of US primary care pediatricians, only 14% of respondents reported receiving follow-on communications from psychiatrists after patient consultation [20]. This lack of communication is likely to also relate to the treatment of adult ADHD. In a survey of general practitioners in the United Kingdom, 43% (19/44) of physicians reported that they were not aware of the reasons for ADHD treatment cessation in patients who initiated treatment as children but stopped treatment before adulthood [21].

These challenges indicate that there is a need to increase awareness of ADHD through continued training of HCPs and the use of screening tools [15,22,23], such as versions of the Adult ADHD Self-Report Scale (ASRS) based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (ASRS v 1.1) [24] and the DSM-5 (ASRS Screener: DSM-5) [25], and the clinician-rated ADHD Rating Scale with adult prompts [26]. In order to address potential knowledge gaps in the diagnosis and treatment of ADHD in HCPs, it is critically important to understand current diagnosis and treatment patterns for adult ADHD. This information will help to better tailor education and training for specific HCP subgroups. Changes in the US healthcare landscape also make it likely that an array of HCP groups, including nurse practitioners (NPs), will play increasingly important roles in diagnosing and treating adult ADHD. Therefore, it was considered important to conduct an HCP-directed survey to enable a better understanding of the diagnosis and treatment patterns for adult ADHD across different HCP subgroups. The objective of this survey was to examine adult ADHD diagnosis and pharmacotherapy treatment patterns in HCPs overall and in specific HCP subgroups (ie, psychiatrists, PCPs, neurologists, and NPs). The focus was on pharmacotherapy because there is a limited evidence base for the nonpharmacologic treatment of adult ADHD [27].

2. Materials and methods

2.1. Study design and participants

This cross-sectional online survey was conducted from May to June 2017. US-based HCPs were recruited by Qessential Medical Market Research (Exeter, NH). Potential respondents were identified from an online database of >600,000 clinicians from various specialties, generated from the American Medical Association. Respondents were ‘self-selected’ in that they had previously indicated that they were willing to participate in research studies and elected to be screened to participate in this study. Four HCP subgroups that treat adults with ADHD [28] were included: psychiatrists, PCPs, neurologists, and NPs. Target sample sizes were 200 each for psychiatrists, PCPs, and neurologists and 100 for NPs, with recruitment ending when the target sample sizes were reached. The target sample size was smaller for NPs because this subgroup was considered to be more difficult to recruit. Survey respondents were compensated (psychiatrists and neurologists received $100; PCPs and NPs received $75) for their time. The study protocol was approved by the Salus Institutional Review Board (Austin, TX), which provided an ethics review. The market research firm and institutional review board had no competing interests regarding this study.

Eligible HCPs were those currently practicing and specializing in psychiatry, primary care practice/family medicine/internal medicine, and neurology/other or who were NPs. Similar to the previous survey [28], participants were also required to be experienced in diagnosing and/or treating ADHD in adults (≥5 patients/month for neurologists and NPs; ≥10 patients/month for psychiatrists and PCPs). The criterion was lowered from ≥10 patients/month to ≥5 patients/month for NPs and neurologists due to slow enrollment when using the more stringent criterion. Participants also needed to be willing to provide informed consent and willing and able to participate in an online survey lasting approximately 20 minutes. Participants were excluded if they practiced primarily in Vermont (because of state regulations that do not allow compensation for study participation) or had no internet access.

2.2. Survey

The survey was developed based on 3 previously conducted surveys: 2 surveys of clinicians on the diagnosis and treatment of adult ADHD [15,28] and 1 survey of adults with ADHD on disease burden and experience with treatment [29]. A draft of the survey was pilot tested with 3 HCPs (a psychiatrist, PCP, and NP), with revisions being made to improve clarity based on HCP feedback. The final survey took approximately 20 minutes to complete and included questions about respondents’ sociodemographic characteristics; ADHD screening, evaluation, and diagnosis practices; ADHD pharmacotherapy prescribing patterns; and perceptions of patient views of ADHD pharmacotherapy. In the current report, questions related to screening referred broadly to identifying ADHD in the total patient population and identifying ADHD among those at high risk or who are exhibiting ADHD symptoms (more commonly referred to as ‘case finding’).

2.3. Data presentation and statistical analyses

Descriptive statistics are reported for each HCP subgroup. For categorical data, values, sample sizes, and percentages are reported. For continuous data, mean ± SD values are reported. Statistical assessment of between-group differences was conducted using chi-square tests for categorical variables and analysis of variance (ANOVA) for continuous variables. When appropriate, post hoc pairwise comparisons were conducted with reference to psychiatrists using the Dunnett test. A similar approach was used for categorical variables using chi-square tests, although this approach did not control for multiplicity. Statistical significance was considered at the 5% level (P < 0.05, 2-tailed). Formal sample size calculations were not conducted; the total target sample size of 700 was considered large enough to provide sufficient precision and power for the analyses.

3. Results

3.1. Participant disposition and characteristics

A total of 702 HCPs completed the survey (201 psychiatrists, 201 PCPs, 200 neurologists, and 100 NPs). Respondent characteristics are summarized in Table 1. The majority of respondents were men (460/702 [65.5%]); mean ± SD age across all respondents was 51.3 ± 10.2 years. The percentages of male respondents and mean age were lowest among NPs (Table 1). The majority of respondents were mostly office- or clinic-based and the percentage of PCPs who were mostly office- or clinic-based was greater than all other HCP subgroups (Table 1). A greater percentage of psychiatrists than non-psychiatrists worked in a solo practice and a greater percentage of non-psychiatrists than psychiatrists worked in a multi-specialty partnership or group of ≥2 physicians (Table 1).

Table 1. Respondent characteristics.

	Psychiatrists n = 201	PCPs n = 201	Neurologists n = 200	NPs n = 100	P Value*
Men, n (%)	138 (68.7)	161 (80.1)	151 (75.5)	10 (10.0)	<0.001
Mean ± SD age, y	53.6 ± 10.7	52.3 ± 9.0	50.7 ± 9.9	45.8 ± 10.4	<0.001
Mean ± SD years since completing medical school	26.6 ± 11.1	25.4 ± 9.1	23.8 ± 10.2	-	0.024
Mean ± SD years since completing medical residency	20.8 ± 10.8	21.4 ± 8.8	18.3 ± 9.9	-	0.003
Mean ± SD years since receiving advanced nursing degree	-	-	-	12.4 ± 8.7
Mean ± SD adult ADHD patients seen per month	40.6 ± 30.8	24.3 ± 18.2	20.7 ± 24.9	22.2 ± 30.0	<0.001
Region, n (%)
South	65 (32.3)	68 (33.8)	63 (31.5)	27 (27.0)	0.532
Northeast	58 (28.9)	48 (23.9)	66 (33.0)	25 (25.0)
Midwest	49 (24.3)	49 (24.3)	40 (20.0)	28 (28.0)
West	29 (14.4)	36 (17.9)	31 (15.5)	20 (20.0)
Type of office/clinic, n (%)^†
Solo practice	63 (35.4)	46 (23.4)	36 (19.4)	5 (6.0)	<0.001
Single-specialty partnership or group (2 or more physicians)	60 (33.7)	86 (43.7)	68 (36.6)	32 (38.6)
Multi-specialty partnership or group (2 or more physicians)	34 (19.1)	65 (33.0)	82 (44.1)	40 (48.2)
Behavioral health-focused partnership with one physician and one or more therapists/psychologists	21 (11.8)	0	0	6 (7.2)
Type of medical practice, n (%)
Mostly office- or clinic-based	150 (74.6)	187 (93.0)	154 (77.0)	76 (76.0)	<0.001
Mostly hospital- or lab-based	12 (6.0)	4 (2.0)	7 (3.5)	8 (8.0)
Exclusively hospital- or lab-based	5 (2.5)	0	5 (2.5)	3 (3.0)
Mostly long-term care facility-based	1 (0.5)	0	1 (0.5)	5 (5.0)
Mostly hospice-based	0	0	1 (0.5)	0
Equally hospital-based and office/clinic-based	28 (13.9)	10 (5.0)	32 (16.0)	7 (7.0)
Other	5 (2.5)	0	0	1 (1.0)
Experience diagnosing adults with ADHD symptoms, n (%)
Yes	201 (100.0)	194 (96.5)	193 (96.5)	86 (86.0)	<0.001
Experience treating adults diagnosed with ADHD, n (%)
Use psychotherapy only	0	0	0	0	<0.001
Use pharmacotherapy only	56 (27.9)	83 (40.8)	110 (55.0)	53 (53.0)
Use both pharmacotherapy and psychotherapy	145 (72.1)	119 (59.2)	84 (42.0)	44 (44.0)
No experience treating adult patients diagnosed with ADHD	0	0	6 (3.0)	3 (3.0)
Knowledge level regarding adult ADHD, n (%)
Extremely knowledgeable	58 (28.9)	15 (7.5)	14 (7.0)	6 (6.0)	<0.001
Very knowledgeable	105 (52.2)	88 (43.8)	65 (32.5)	35 (35.0)
Somewhat knowledgeable	37 (18.4)	91 (45.3)	107 (53.5)	53 (53.0)
Not very knowledgeable	1 (0.5)	7 (3.5)	13 (6.5)	6 (6.0)
Not at all knowledgeable	0	0	1 (0.5)	0
Quality of education and/or training received on adult ADHD, n (%)
Received extremely thorough training	48 (23.9)	8 (4.0)	5 (2.5)	6 (6.0)	<0.001
Received moderate amount of training	79 (39.3)	56 (27.9)	59 (29.5)	30 (30.0)
Received some training	56 (27.9)	79 (39.3)	76 (38.0)	35 (35.0)
Received very limited training	15 (7.5)	53 (26.4)	48 (24.0)	22 (22.0)
Received no training at all	3 (1.3)	5 (2.5)	12 (6.0)	7 (7.0)
Most valuable additional education/training on adult ADHD, n (%)
Conferences	72 (35.8)	56 (27.9)	66 (33.0)	26 (26.0)	0.010
CME	93 (46.3)	114 (56.7)	94 (47.0)	55 (55.0)
Medical science liaison engagement	6 (3.0)	11 (5.5)	18 (9.0)	2 (2.0)
Online non-CME reference materials	16 (8.0)	16 (8.0)	18 (9.0)	12 (12.0)
Other	14 (7.0)	4 (2.0)	4 (2.0)	5 (5.0)

ADHD = attention-deficit/hyperactivity disorder; CME = continuing medical education; NP = nurse practitioner; PCP = primary care physician.

*Based on overall comparison across HCP subgroups.

^†Based on 178 psychiatrists, 197 PCPs, 186 neurologists, and 83 nurses.

Table 2. Perceptions regarding diagnosis, screening, and optimal treatment regimen for ADHD in adults.

	Psychiatrists n = 201	PCPs n = 201	Neurologists n = 200	NPs n = 100	P Value*
I am confident in my ability to diagnose ADHD in adults [score], n (%)
Strongly agree [7]	101 (50.2)^‡‡‡	32 (15.9)^†††	33 (16.5)^†††	9 (9.0)^†††	<0.001
Agree [6]	74 (36.8)	86 (42.8)	88 (44.0)	42 (42.0)
Somewhat agree [5]	16 (8.0)	45 (22.4)	49 (24.5)	21 (21.0)
Neither agree nor disagree [4] to strongly disagree [1]	10 (5.0)	38 (18.9)	30 (15.0)	28 (28.0)
Mean ± SD score^§	6.26 ± 1.05^‡‡‡	5.42 ± 1.26^†††	5.51 ± 1.19^†††	4.99 ± 1.54^†††	<0.001
There are clear criteria for diagnosing ADHD in adults [score], n (%)
Strongly agree [7] and agree [6]	64 (31.8)^‡‡‡	48 (23.9)^††	42 (21.0)^†††	12 (12.0)^†††	<0.001
Somewhat agree [5]	66 (32.8)	44 (21.9)	44 (22.0)	19 (19.0)
Neither agree nor disagree [4]	20 (10.0)	35 (17.4)	47 (23.5)	18 (18.0)
Somewhat disagree [3]	33 (16.4)	48 (23.9)	37 (18.5)	34 (34.0)
Disagree [2] and strongly disagree [1]	18 (9.0)	26 (12.9)	30 (15.0)	17 (17.0)
Mean ± SD score^§	4.68 ± 1.41^‡‡‡	4.20 ± 1.49^††	4.16 ± 1.43^†††	3.76 ± 1.34^†††	<0.001
I would take a more active role in diagnosis and treatment if an easy-to-use, validated screening tool were available [score], n (%)
Strongly agree [7]	24 (11.9)^‡‡‡	39 (19.4)^††	33 (16.5)^†††	23 (23.0)^†††	<0.001
Agree [6]	53 (26.4)	70 (34.8)	76 (38.0)	49 (49.0)
Somewhat agree [5]	45 (22.4)	43 (21.4)	49 (24.5)	17 (17.0)
Neither agree nor disagree [4] to strongly disagree [1]	79 (39.3)	49 (24.4)	42 (21.0)	11 (11.0)
Mean ± SD score^§	4.81 ± 1.50^‡‡‡	5.25 ± 1.52^††	5.36 ± 1.30^†††	5.71 ± 1.27^†††	<0.001
It is difficult to determine optimal ADHD treatment regimen for adult patients [score], n (%)^║
Strongly agree [7]	6 (3.0)^‡‡	12 (6.0)^††	6 (3.1)	6 (6.2)	0.016
Agree [6]	32 (15.9)	49 (24.4)	44 (22.7)	24 (24.7)
Somewhat agree [5]	52 (25.9)	59 (29.4)	64 (33.0)	28 (28.9)
Neither agree nor disagree [4]	31 (15.4)	37 (18.4)	34 (17.5)	9 (9.3)
Somewhat disagree [3]	44 (21.9)	18 (9.0)	27 (13.9)	19 (19.6)
Disagree [2]	30 (14.9)	22 (10.9)	16 (8.2)	7 (7.2)
Strongly disagree [1]	6 (3.0)	4 (2.0)	3 (1.5)	4 (4.1)
Mean ± SD score^§	4.06 ± 1.50^‡‡‡	4.59 ± 1.47^†††	4.53 ± 1.36^††	4.51 ± 1.57^†	0.001

ADHD = attention-deficit/hyperactivity disorder; HCP = healthcare provider; NP = nurse practitioner; PCP = primary care physician.

*Based on overall comparison across HCP subgroups.

^†P < 0.05, ^††P ≤ 0.01, ^†††P ≤ 0.001 for pairwise comparisons vs psychiatrists.

^‡‡P ≤ 0.01, ^‡‡‡P ≤ 0.001 for psychiatrists vs all non-psychiatrist subgroups combined.

^§Calculated based on designated values (as noted by the bracketed number) for each response; smaller values indicate less agreement (more disagreement) with the statement.

^║Based on n = 201 for psychiatrists, n = 201 for PCPs, n = 194 for neurologists, and n = 97 for NPs.

Across all respondents, 42.9% (301/702) reported using pharmacotherapy only to treat adult ADHD and 55.8% (392/702) reported using both pharmacotherapy and psychotherapy. The use of both pharmacotherapy and psychotherapy was greatest in psychiatrists and lowest in neurologists (Table 1). There was a significant difference across subgroups in the percentage of respondents reporting that they were extremely or very knowledgeable about adult ADHD (P < 0.001), with the percentage being greatest in psychiatrists and least in neurologists (Table 1). There was also a significant difference (P < 0.001) across HCP subgroups regarding the quality of education/training for adult ADHD. Greater percentages of psychiatrists than non-psychiatrists reported receiving extremely thorough training and moderate training (Table 1). Receiving some training to no training in adult ADHD was reported by 36.8% (74/201) of psychiatrists.

3.2. Diagnosis and screening of adults with ADHD

Significantly greater percentages of psychiatrists than non-psychiatrists reported being confident in their ability to diagnose adult ADHD (all P < 0.001 vs psychiatrists; Table 2) and strongly agreed that clear criteria exist for diagnosing ADHD in adults (all P ≤ 0.005 vs psychiatrists; Table 2). Furthermore, a significantly greater percentage of psychiatrists than non-psychiatrists reported always screening or evaluating for ADHD in patients with depression and anxiety disorders (all P < 0.001 vs psychiatrists; Figure 1(a)). Lack of appropriate screening/evaluation measures for adult ADHD and inexperience with screening/evaluating adult ADHD were reported as reasons for not screening for ADHD in patients with depression/anxiety disorders by significantly greater percentages of non-psychiatrists than psychiatrists (both P ≤ 0.001; Figure 1(b)).

Figure 1. (a) Frequency of screening/evaluating and (b) reasons for not screening for ADHD in patients with depression/anxiety disorders.

ADHD = attention-deficit/hyperactivity disorder; HCP = healthcare provider; NP = nurse practitioner; PCP = primary care physician. *P < 0.05, ***P ≤ 0.001 for pairwise comparisons vs psychiatrists.^†††P ≤ 0.001 for overall HCP subgroup comparisons.^‡‡‡P ≤ 0.001 for psychiatrists vs all non-psychiatrist subgroups combined.

A significantly greater percentage of psychiatrists reported that they never referred patients for diagnosis (61.7% [124/201]) compared with PCPs (9.0% [18/201]), neurologists (23.0% [46/200]), and NPs (11.0% [11/100]) (all P < 0.001). The most frequently reported reasons for referral among all respondents were to obtain a second opinion/confirm diagnosis (367/503 [73.0%]) and concerns about pharmacotherapy options (239/503 [47.5%]). Compared with psychiatrists, significantly greater percentages of non-psychiatrists reported the following reasons for referring patients to a specialist for diagnosis (Figure 2(a)): concerns about pharmacotherapy options (PCPs, neurologists, and NPs; all P ≤ 0.033 vs psychiatrists), time constraints during appointments (PCPs, neurologists, and NPs; all P ≤ 0.001 vs psychiatrists), no clear diagnostic criteria for adult ADHD (PCPs and neurologists; both P ≤ 0.047 vs psychiatrists), and lack of experience diagnosing adult ADHD (NPs; P = 0.003 vs psychiatrists). Significantly greater percentages of non-psychiatrists than psychiatrists also reported that they would take a more active role in diagnosing and treating adult ADHD if improved screening tools were available (all P ≤ 0.005 vs psychiatrists; Table 2).

Figure 2. (a) Reasons for referring adult patients to a specialist for diagnosis of ADHD or (b) to a psychiatrist/specialist for treatment of ADHD.

ADHD = attention-deficit/hyperactivity disorder; HCP = healthcare provider; NP = nurse practitioner; PCP = primary care physician.*P < 0.05, **P ≤ 0.01, ***P ≤ 0.001 for pairwise comparisons vs psychiatrists.^†P < 0.05, ^†††P ≤ 0.001 for overall HCP subgroup comparisons.^‡P < 0.05, ^‡‡‡P ≤ 0.001 for psychiatrists vs all non-psychiatrist subgroups combined.^§Psychiatrists were not asked this question.^║P < 0.05 for PCPs vs NPs.^¶P < 0.05 for neurologists vs NPs.

Among non-psychiatrists, the most frequently reported reasons for patient referral to a specialist for treatment were to obtain a second opinion/confirm diagnosis and concerns about pharmacotherapy options (Figure 2(b)).

3.3. Pharmacotherapy decisions and prescribing patterns for adult ADHD

Pharmacotherapies prescribed to the greatest mean percentage of patients were long-acting (LA) and short-acting (SA) amphetamine-based agents; pharmacotherapies prescribed to the smallest mean percentage of patients were SA nonstimulants (Figure 3(a)). Across all respondents, the most frequently reported pharmacotherapeutic regimens considered effective for treating adult ADHD symptoms throughout the day were once-daily LA stimulants and LA stimulants plus an adjunctive SA stimulant (Figure 3(b)).

Figure 3. Percentage of patients treated using (a) drug classes/formulations currently prescribed and (b) pharmacotherapy treatment regimens considered effective for treating ADHD symptoms throughout the day.

ADHD = attention-deficit/hyperactivity disorder; AMP = amphetamine; HCP = healthcare provider; LA = long-acting; MPH = methylphenidate; NP = nurse practitioner; PCP = primary care physician; SA = short-acting.*P < 0.05, **P ≤ 0.01, ***P ≤ 0.001 for pairwise comparisons vs psychiatrists.^†P < 0.05, ^††P ≤ 0.01, ^†††P ≤ 0.001 for overall HCP subgroup comparisons.^‡‡P ≤ 0.01, ^‡‡‡P ≤ 0.001 for psychiatrists vs all non-psychiatrist subgroups combined.

Significantly greater percentages of psychiatrists than non-psychiatrists prescribed once-daily LA stimulants (71.6% [144/201] for psychiatrists vs 62.2% [306/492] for all non-psychiatrists combined, P = 0.023) or SA stimulants more than once daily (40.3% [81/201] for psychiatrists vs 29.7% [146/492] for all non-psychiatrists combined, P = 0.009) as first-line pharmacotherapies (Figure 4(a)). In contrast, a significantly greater percentage of non-psychiatrists than psychiatrists prescribed once-daily SA stimulants (32.9% [162/492] for all non-psychiatrists combined vs 17.4% [35/201] for psychiatrists; P < 0.001; Figure 4(a)). The most frequently reported reasons for prescribing once-daily LA medications as first-line pharmacotherapy were personal/professional preference, patient lifestyle, and patient preference (Figure 4(b)).

Figure 4. (a) First-line pharmacotherapies for adult ADHD patients and (b) factors contributing to use of a once-daily long-acting stimulant.

ADHD = attention-deficit/hyperactivity disorder; HCP = healthcare provider; LA = long-acting; NP = nurse practitioner; PCP = primary care physician; SA = short-acting.*P < 0.05, **P ≤ 0.01, ***P ≤ 0.001 for pairwise comparisons vs psychiatrists.^†P < 0.05, ^†††P ≤ 0.001 for overall HCP subgroup comparisons.^‡P < 0.05, ^‡‡P ≤ 0.01, ^‡‡‡P ≤ 0.001 for psychiatrists vs all non-psychiatrist subgroups combined.

Compared with psychiatrists, significantly greater percentages of all non-psychiatrists (combined) agreed it was difficult to determine an optimal ADHD treatment regimen for adults with ADHD (P = 0.005 vs psychiatrists; Table 2), with mean rating scores for psychiatrists being significantly lower (indicating lower agreement) than for all non-psychiatrists combined (P < 0.001) and each individual non-psychiatrist HCP subgroup (all P ≤ 0.039 vs psychiatrists). Across all HCPs, the factors deemed most important to patients when choosing pharmacotherapy were insurance coverage/cost of treatment (554/693 [79.9%]), perceived duration of effect (500/693 [72.2%]), and side effects (461/693 [66.5%]). Significantly greater percentages of psychiatrists than non-psychiatrists reported that the important factors in patients’ choosing a pharmacologic treatment regimen were the medication’s perceived duration of effect, onset of effect, and side effect profile, as well as physician recommendation (all P ≤ 0.005 vs psychiatrists; Figure 5(a)). HCPs reported that the greatest mean ± SD percentages of patients changed their pharmacotherapy in the past 6 months because of perceptions of insufficient duration of effect (35.4% ± 22.1%) and lack of efficacy (30.3% ± 21.0%), with a significantly greater percentage of psychiatrists than NPs reporting that patients changed their pharmacotherapy because of perceived lack of efficacy (P = 0.006 vs psychiatrists; Figure 5(b)).

Figure 5. (a) Factors contributing to patients choosing and (b) changing their ADHD pharmacotherapy.

ADHD = attention-deficit/hyperactivity disorder; HCP = healthcare provider; NP = nurse practitioner; PCP = primary care physician.*P < 0.05, **P ≤ 0.01, ***P ≤ 0.001 for pairwise comparisons vs psychiatrists.^†P < 0.05, ^††P ≤ 0.01, ^†††P ≤ 0.001 for overall HCP subgroup comparisons.^‡P < 0.05, ^‡‡P ≤ 0.01, ^‡‡‡P ≤ 0.001 for psychiatrists vs all non-psychiatrist subgroups combined.

4. Discussion

This study highlights the need for additional HCP training regarding the screening, diagnosis, and pharmacotherapeutic treatment of adult ADHD, based on HCP-perceived deficits in knowledge and training, and describes differential diagnosis and pharmacotherapy treatment patterns for adult ADHD across HCP subgroups. Non-psychiatrists reported being less knowledgeable about, less trained regarding, and less confident in their ability to treat adult ADHD. As expected, a greater percentage of non-psychiatrists reported that they referred patients for diagnosis than did psychiatrists. Furthermore, they felt that criteria for diagnosing adult ADHD were unclear, reported experiencing greater difficulty determining the optimal treatment for their adult ADHD patients, and more commonly referred patients to psychiatrists/specialists for diagnosis and/or treatment than psychiatrists. With regard to pharmacotherapy prescribing patterns, greater percentages of non-psychiatrists prescribed once-daily SA stimulants and lower percentages considered LA stimulants and SA stimulants taken more than twice daily to be effective to treat ADHD symptoms throughout the day. The pharmacotherapeutic treatment regimen considered most effective across HCPs was a once-daily LA stimulant, which a greater percentage of psychiatrists than non-psychiatrists prescribed. Perceived duration of effect was an important factor in choosing a pharmacotherapy, and perceived insufficient duration of effect was the most frequently reported reason for changing a patient’s pharmacotherapy.

In this study, a percentage of each HCP subgroup reported deficits in their knowledge of adult ADHD and in the quality of their training regarding adult ADHD. These perceived deficits were reported by greater percentages of non-psychiatrists than psychiatrists. These findings are consistent with previously published surveys, which reported that a smaller percentage of PCPs than psychiatrists was extremely confident in diagnosing and/or treating adult ADHD [30] and that a smaller percentage of nurses than physicians was comfortable/very comfortable in their ability to recognize ADHD symptoms in young adults [16]. Importantly, the percentages of PCPs, neurologists, and NPs who reported being extremely knowledgeable or highly trained regarding adult ADHD were low (<10%), which suggests a substantive lack of training during or after residency or internship and/or limited experience treating adult ADHD. Similar findings were observed in a cross-sectional study of PCPs in Saudi Arabia, which reported that 32% of PCPs had poor knowledge of ADHD and more than 60% relied on self-learning [18].

The greater perceived deficits in knowledge and training in non-psychiatrists may be a factor leading to their lower confidence in diagnosing adult ADHD and their subsequent referral of patients to specialists for diagnosis and/or treatment. The lower confidence of non-psychiatrists compared with psychiatrists could also be related to the fact that psychiatrists treated almost twice the number of patients each month than did non-psychiatrists or to the lower perception of non-psychiatrists than psychiatrists that there are clear diagnostic criteria for adult ADHD. This perception is of concern because the diagnostic criteria for adult ADHD are clearly described in the DSM-5 [14]. This diagnostic uncertainty for adults might be a vestige of concerns that ADHD was previously conceptualized solely as a childhood disorder and should be a focus of future educational programs.

The perceived insufficiencies in knowledge and training of non-psychiatrists are important issues because these HCP groups are involved in the care of patients with adult ADHD [31–33]. Even among psychiatrists, nearly 30% of respondents reported receiving limited or no training in adult ADHD, and 25% disagreed that there are clear diagnostic criteria for adult ADHD. These and other findings emphasize the need for increased education and training in screening, diagnosing, and treating adult ADHD. This training should focus on increasing awareness of available screening tools, such as the ASRS Screener: DSM-5 [25] and the clinician-rated ADHD Rating Scale with adult prompts [26], and on clarifying diagnostic criteria in adults in all HCP groups.

Adult ADHD is often comorbid with depression and anxiety disorders, and it has been suggested that these comorbidities may contribute to the misdiagnosis or underdiagnosis of ADHD [22,34,35]. In support of the possibility that comorbid depression or anxiety can influence ADHD diagnosis, the study found that a lower percentage of non-psychiatrists than psychiatrists screened/evaluated for ADHD in patients with depression/anxiety disorders. These findings are consistent with those of a previously published survey of PCPs and psychiatrists [30]. In that survey, although 77% and 73% of respondents recognized that depression and anxiety, respectively, were frequent comorbidities in adults with ADHD, <15% of respondents screened for ADHD in patients presenting with symptoms of depression or anxiety [30]. A survey of general practitioners in the United Kingdom also reported that more than 60% of patients were treated for comorbidities before being diagnosed with ADHD [21]. In further support of the view that depression and anxiety symptoms can influence ADHD diagnosis, it has been reported that the presence of a preexisting diagnosis of anxiety or depression is associated with a delay in the diagnosis of ADHD in adults [36]. Taken together, these data highlight the importance of not only educating HCPs regarding potential symptom overlap among anxiety disorders, depression, and ADHD [34,35], but also of screening for ADHD in patients who exhibit symptoms of anxiety and depression.

A greater percentage of non-psychiatrists than psychiatrists referred patients to a specialist and/or psychiatrist for diagnosis and treatment. This difference in referral patterns among HCP subgroups is consistent with observations from another survey [16], which reported that a greater percentage of nurses than counseling directors or physicians referred young adults for ADHD evaluation. Heavy dependence on specialists was also observed in a survey of Saudi Arabian PCPs, who referred 73% of diagnosed ADHD cases to specialists [18]. Although reasons for referral were not reported in these surveys [16,18], the most frequently reported reasons for patient referral among non-psychiatrists in the current study included obtaining a second opinion and concerns about treatment options. In a survey of PCPs and psychiatrists [30], the greatest barrier to adult ADHD diagnosis was reported to be a lack of experience in diagnosing ADHD. Although lack of experience was not among the most commonly reported reasons for referral in the current study, it was reported as a reason for referral by a significantly greater percentage of non-psychiatrists than psychiatrists. With regard to referral practices among non-psychiatrists, it is important to note that there was substantial variance within the subgroups. This finding is consistent with the distribution of responses regarding confidence in diagnosing ADHD.

The reported difficulty of non-psychiatrists in determining the optimal treatment for their adult patients with ADHD may be related to the limited guidance available regarding the pharmacotherapy for adult ADHD [8,11,37] and the multitude of pharmacotherapeutic options available for adult ADHD [9]. A greater percentage of HCPs reported prescribing stimulants than nonstimulants in this study, with amphetamine-based agents prescribed by a greater percentage of HCPs than methylphenidate-based agents. Prescribing patterns regarding stimulants versus nonstimulants may be reflective of the larger treatment effect sizes versus placebo for stimulants compared with nonstimulants in adults [38]. It should also be noted that a greater percentage of psychiatrists than non-psychiatrists currently prescribed SA nonstimulants. The increased use of nonstimulants by psychiatrists could be related to their treatment of patients with comorbid psychiatric conditions, such as anxiety disorders [12].

Once-daily LA stimulants were prescribed by the greatest percentage of HCPs as first-line pharmacotherapy and were considered to be effective in treating ADHD throughout the day by the greatest percentage of HCPs. This suggests that HCPs recognize that ADHD symptoms are present throughout the day and require a pharmacotherapeutic treatment regimen that lasts throughout the day, as has been previously emphasized [9]. The importance of treating ADHD symptoms throughout the day with LA pharmacotherapies is further supported by the perceived importance of duration of effect in making treatment decisions. HCPs perceived that duration of effect was among the most important factors influencing pharmacotherapy choice by their patients – second only to insurance coverage/costs – and reported that perceived insufficient duration of effect was the most frequent reason for changing a patient’s pharmacotherapy. Although a majority of non-psychiatrists recognized the importance of perceived duration of effect in choosing a pharmacotherapy (65.2% to 69.1%), a substantial minority (28.9% to 36.1%) prescribed once-daily SA stimulants as first-line pharmacotherapy. This observed prescribing pattern among non-psychiatrists is consistent with published reports, which indicate that approximately 20% to 40% of adults with ADHD are prescribed SA stimulant monotherapy for treating ADHD [39,40]. This indicates that the knowledge of non-psychiatrist HCPs may not be entirely consistent with their prescribing practices. The use of SA stimulants in adults with ADHD is also a concern because these agents, which are not approved for use in adults with ADHD, are used by a substantial proportion of adults with ADHD [40] and may have increased liability for misuse and diversion than LA formulations [41,42]. This is an important aspect of the pharmacologic treatment of ADHD that should be a focus for education.

It is important to note that there were differences in perceptions and prescribing patterns for pharmacotherapy between psychiatrists and non-psychiatrists. Compared with psychiatrists, a greater percentage of non-psychiatrists considered once-daily SA stimulants to be effective in managing ADHD symptoms throughout the day. Conversely, a smaller percentage of non-psychiatrists considered stimulant combinations or more than once-daily LA or SA stimulants to be effective in managing ADHD symptoms throughout the day. These views appeared to influence first-line pharmacotherapy prescribing patterns, as greater percentages of non-psychiatrists than psychiatrists prescribed once-daily SA stimulants, and were consistent with the fact that smaller percentages of non-psychiatrists than psychiatrists perceived duration of effect to be an important factor in a patient’s choice of pharmacotherapy.

There are several limitations related to potential selection bias that should be considered when interpreting these data. Several aspects of the study limit the ability to generalize these findings to the overall population of HCPs in the United States who diagnose and treat adult ADHD. Study respondents were recruited through a database of HCPs willing to participate in research studies. As such, these ‘self-selected’ respondents were not chosen at random. Furthermore, although participants were recruited from across the United States, analyses were not conducted to confirm that participants were representative of the overall HCP population in the United States. It should also be noted that the current analyses included a broad PCP subgroup that may have comprised physicians from varying specialties (ie, family physicians, internists, gerontologists, etc) who self-identified as PCPs. As psychiatric training across these specialties varies, it would be expected that different levels of training and knowledge would be observed if a subanalysis of PCP specialties was conducted. Lastly, only HCPs treating ≥5 (neurologists and NPs) or ≥10 (psychiatrists and PCPs) adults with ADHD per month were included in the study and the sample size for NPs was relatively small. Therefore, these results may not reflect the perceptions of HCPs who diagnose or treat adult ADHD less frequently or of the general population of NPs.

5. Conclusion

Understanding the differences in HCP knowledge, training, and pharmacologic treatment patterns is important for tailoring resources, implementing tools that facilitate pharmacologic treatment decisions, and helping optimize patient outcomes so that care is more patient centric. This report indicates that all HCP subgroups perceived some level of deficit in their knowledge, training, and confidence regarding the screening, diagnosis and treatment, and pharmacologic treatment of adult ADHD. However, these deficits were more pronounced in non-psychiatrists than psychiatrists. An important next step will be to determine if the lack of knowledge regarding adult ADHD diagnosis and treatment is due to insufficiencies in training or due to the inability of some HCPs to become sufficiently knowledgeable because their workload does not allow for the required training. This study also demonstrates that psychiatrists and non-psychiatrists have different preferred pharmacotherapy prescribing patterns, with approximately one-third of non-psychiatrists prescribing once-daily SA stimulants as first-line pharmacotherapy despite the recognition of the importance of the perceived duration of medication effect as a factor in a patient’s choice to initiate and maintain a pharmacotherapy by approximately two-thirds of non-psychiatrists. Further analyses of the doses prescribed by HCP subgroups using a claims database would provide additional insight into prescribing patterns across HCP subgroups. Taken together, these findings emphasize the need for continued education and training regarding adult ADHD diagnostic criteria, the screening tools available for adult ADHD, and pharmacologic treatment recommendations for adult ADHD.

Declaration of interest

In the past 3 years, L. A. Adler has received grant/research support from Sunovion Pharmaceuticals, Enzymotec, Shire Pharmaceuticals, and Lundbeck; has served as a consultant to Bracket, Enzymotec, Alcobra Pharmaceuticals, Sunovion Pharmaceuticals, Shire Pharmaceuticals, Otsuka Pharmaceuticals, the National Football League, and Major League Baseball; and has received royalty payments (as inventor) from NYU for license of adult ADHD scales and training materials. He has no conflicts in regard to stock ownership or speakers bureaus.

S. Farahbakhshian is an employee of Shire, a member of the Takeda group of companies, and holds Takeda stock and/or stock options.

B. Romero is an employee of ICON, which was funded by Shire, a member of the Takeda group of companies, to perform the study.

E. Flood and H. Doll are former employees of ICON, which was funded by Shire, a member of the Takeda group of companies, to perform the study. E. Flood is currently an employee of AstraZeneca (Gaithersburg, MD, USA) and H. Doll is currently an employee of Clinical Outcomes Solutions (Folkstone, Kent, UK). Peer reviewers on this manuscript have no conflicts of interest to disclose.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Acknowledgments

The authors would like to thank Alexandra Khachatryan, MPH, for her contributions to the development of this study. Under the direction of the authors, writing assistance was provided by Wendy van der Spuy, PhD, and Craig Slawecki, PhD, employees of CHC. Editorial assistance in proofreading, copyediting, and fact checking was also provided by CHC. Shailesh Desai, PhD from Shire Development LLC, a member of the Takeda group of companies, also reviewed and edited the manuscript for scientific accuracy.

Additional information

Funding

This research was funded by Shire Development LLC, Lexington, MA, USA, a member of the Takeda group of companies. Shire Development LLC, a member of the Takeda group of companies, provided funding to Complete Healthcare Communications, LLC (CHC; North Wales, PA), a CHC group company, for support in writing and editing this manuscript.