Does Extended Release Methylphenidate Help Adults with Hoarding Disorder? A Case Series

To the Editors

Individuals with Hoarding Disorder (HD),¹ a proposed diagnosis for DSM-V, commonly self-report poor attention^2,3 and have significant impairments on objective measures of attention (e.g., the Continuous Performance Test [CPT]).^4,5 Problems with attention may contribute to difficulty making decisions and lead to the accumulation of clutter.⁶ A single case report of an individual with hoarding disorder and attention-deficit/hyperactivity disorder (ADHD) suggested that amphetamine salts may provide benefits in self-reported attention and some aspects of hoarding such as procrastination.⁷ However, to our knowledge, no study has tested the effects of stimulants in individuals with hoarding disorder without co-morbid ADHD. Therefore, we tested if adjunctive methylphenidate extended release (MPH-ER),⁸ a stimulant with proven efficacy in improving attention, can increase attention on both self-report and objective measures and decrease hoarding symptoms in individuals that met the proposed DSM-V criteria for HD¹ but did not have comorbid ADHD.

Four adults (age 18 to 50) who met the HD criteria proposed by Frost and Hartl⁹ (assessed by the Hoarding Rating Scale-Interview [HRS-I]¹⁰) and who had clinically significant hoarding (a Saving Inventory-Revised [SI-R]¹¹ score ≥ 40) were recruited from the community between April 2010 and July 2010. During the study, the proposed DSM-V criteria for HD were published,¹ and all subjects met these additional criteria (i.e. hoarding symptoms not due to a medical condition [assessed by medical history and exam] and were not restricted to symptoms of another mental disease [assessed by SCID and psychiatric exam]). One patient had comorbid Obsessive Compulsive Disorder (OCD) but the hoarding symptoms were clearly independent from the OCD (i.e., mild symptoms of needing to count choir members to a certain number or else she did not “feel right”). The institutional review board approved this study, and all subjects provided written informed consent. None met DSM-IV criteria for ADHD, but all reported at least moderate attention problems (an Adult Attention Subscale score ≥ 8 on the ADHD Symptom Scale [ADHDSS]¹²). Two of the four subjects were on medications as shown in Table 1, but these medications were stable prior to study entry (12 weeks for serotonin reuptake inhibitors [SRIs] or serotonin and norepinepherine reuptake inhibitors [SNRIs] and 4 weeks for others). Subjects were excluded for current use of any type of stimulant medication or psychotherapy, comorbid psychiatric or medical conditions that increased the risk of participation, and history of methylphenidate use.

Table 1. Clinical Characteristics of Hording Disorder Subjects.

Clinical characteristics, treatment history, and outcome of four HD patients treated with adjunctive methylphenidate extended release (MPH-ER) for 4 weeks. The continuous performance task (CPT) is reported at the interstimulus intervals of 1000milliseconds and 4000 milliseconds, with the reaction time standard deviation (SD) and mean reaction time also reported in units of milliseconds.

Pt No	Age/Sex	Race	Comorbid Dx SCID	Prior SRI/ SNRI Trials	Current Medications	Maximum MPH-ER Dose	Side Effects	ADHDSS Score Pre/Post	SI-R Score Pre/ Post/% reduction	Mean Reaction Time CPT (ISI=1000) re/Post/% reduction	Mean Reaction Time CPT (ISI=4000) re/Post/% reduction	Reaction Time SD CPT (ISI=1000) re/Post/% reduction	Reaction Time SD CPT (ISI=4000) re/Post/% reduction
1	48/F	AA	OCD, MDD Specific Phobia	3	None	54mg	Insomnia	19/20 (↓ 0%)	75/75 (↓ 0%)	395/386 (↓ 2%)	458/452 (↓ 1%)	58/39 (↓ 33%)	72/48 (↓ 34%)
2	45/F	C	MDD, Social Phobia	1	None	36mg	Palpitations	30/10c (↓ 67%)	59/40d (↓ 32%)	430/391 (↓ 9%)	489/461 (↓ 6%)	118/64 (↓ 46%)	123/322 (↓ 6%) c
3	42/M	C	MDD	3	Duloxetine, a escitalopram, bupropion	54mg	Insomina	20/10 c (↓ 50%)	64/62 (↓ 0%) c	424/414 (↓ 2%)	584/499 (↓ 15%)	71/51 (↓ 28%)	156/73 (↓ 53%)
4	36/F	C	Dysthymia, GAD	3	Citalopram, b clonazepam	54mg	Insomina, headache, decreased appetite	43/16 c (↓ 63%)	71/53d (↓ 25%) c	476/390 (↓ 18%)	467/436 (↓ 7%) c	122/83 (↓ 32%)	98/94 (↓ 4%)

AA, African American; ADHDSS, ADHD Symptom Scale; C, Caucasian; CPT, continuous performance test response time; F, female; GAD, generalized anxiety disorder; ISI, interstimulus interval; M, male; MDD, major depressive disorder; OCD, obsessive-compulsive disorder; SI-R, Saving Inventory-Revised; SRI, serotonin reuptake inhibitor; SNRI, serotonin and norepinephrine reuptake inhibitor.

^aPatient #3, duloxetine 30mg daily, escitalopram 10mg daily, bupropion 300mg daily, all stable for 15 years

^bPatient #4, citalopram 60mg daily for 12 weeks, clonazepam 2mg daily for 8 weeks

^c>30% reduction in ADHDSS

^d>25% reduction in SI-R

All subjects completed the four week trial of MPH-ER. MPH-ER was started at 18mg/day and increased by 18mg per week to a maximum of 72mg/day. Weekly dose increases occurred only if clinically indicated¹³ and tolerated. At baseline (week 0) and at study end (week 4), subjects completed one measure of hoarding symptoms (self–report [SI-R]) and two measures of attention (self-report [ADHDSS] and objective [CPT]). The CPT includes the following measures of attention: correct hits, omission errors, commission errors, mean hit reaction time (decreased reaction time indicates improved attention), and the standard error of the mean hit reaction time (an indication of the consistency with which respondents can focus their attention). To evaluate safety, patients were assessed for new-onset tics,¹⁴ and symptoms of psychosis,¹⁵ mania,¹⁶ OCD,¹⁷ and depression. Response was defined as an ADHDSS reduction of at least 30%, as used in prior research;¹³ the ADHDSS has shown excellent reliability in prior studies of individuals with HD.^{2, 18}

Clinical characteristics of the four subjects are shown in Table 1. All had previously tried and failed at least 1 SRI. At baseline, all subjects exceeded the criteria for clinically significant hoarding (SI-R score ≥ 40); the mean SI-R (SD) was 67.3 (7.1).

After four weeks of MPH-ER with mean dose of 50mg (9mg), three of four patients (75%) had a ≥ 50% reduction in inattention, as measured by the self-report ADHDSS. At baseline, all 4 subjects had high hit rates (97%-100%) and minimal omission or commission errors (mean omission=0.16; mean commission= 1.16). Thus, there was little room for change at week 4, and little change was seen. As shown in Table 1, the mean response time mildly decreased (2–18% [ISI=1000]; 1–15% [ISI=400]), indicating improved attention in the CPT task. Furthermore, all 4 subjects had decreases in response time standard deviations from baseline (28–46% reductions [ISI=1000]; 4–53% [ISI=4000]), indicating improved ability to sustain attention. Two of four subjects had a modest reduction in hoarding symptoms (25% and 32%), as measured by the SI-R. Inspection of the SI-R subscale symptom domains (i.e., clutter, difficulty discarding, and excessive acquisition) showed that the majority of the reduction in hoarding symptoms in these two subjects were in the excessive acquisition domain.

There were no new-onset symptoms of tics, psychosis, mania, or worsening OCD symptoms or depression. On the other hand, none of the patients chose to continue taking MPH-ER after study end because they did not like the adverse effects (e.g. insomnia, palpitations).

There are several limitations of this small, open-label case series. First, improvements in the CPT may be due to repeated administration of the CPT, rather than real improvements in attention. Second, the ADHDSS rating scale that was used to measure attention symptoms has not been validated for use in individuals without ADHD.

This case series suggests that adjunctive MPH-ER can reduce self-reported and objective inattention without causing new-onset psychiatric symptoms. In two of the four cases, there were also modest reductions of hoarding symptoms, comparable to what has been found in treatment studies of hoarding disorder,¹⁹ specifically in the excessive acquisition domain. At the same time, these four subjects decided that the benefits of MPH-ER on attention or hoarding did not outweigh the costs. Future research is warranted to determine whether amphetamine compounds also benefit specific domains of hoarding disorder.