Table 2.
N of 1 (Nonrandomized) Trials of Treatments for Aggression in Adults with Autism Spectrum Disorder
| Study | Diagnosis | Nature of aggression | Study design | Intervention | Outcome | Limitations |
|---|---|---|---|---|---|---|
| Hughes & Davis (1980)85 | Autistic disorder (DSM-III19) | Hitting and kicking others, batting with head, throwing objects | A-B-A | Training subject to attempt to relax in face of aggression-inducing stimuli by providing verbal praise and positive reinforcement (pennies) each time subject attempted to relax Awareness of relaxation status/attempts conveyed to subject via electromyographic biofeedback |
Marked reduction in number and frequency of aggressive responses (from 19 during first 4 baseline sessions to 6.25 during first 4 intervention sessions, to 13 during next set of baseline sessions, which, although higher than during preceding sessions, represented improvement from initial baseline) | Lack of control procedures used to assess contribution of habituation alone (i.e., continued presence of an aggression-provoking stimulus) in producing observed reduction in aggressive responses (i.e., time-varying confounding) Unblinded outcome assessors |
| McKeegan et al. (1984)86 | Autism (DSM-III19) Profound ID 24 y.o. man |
Aggressive and self-injurious behavior (unspecified) | A-B (quasi-experimental with extended follow-up) | Non-exclusionary timeout program: 2-minute period during which ribbon (and associated edible- and praise-based reinforcement of appropriate behavior) removed from subject upon occurrence of aggressive behavior |
Substantial decrease in aggressive behavior, with clinical gains maintained at 25-day (mean = 0.25 occurrences/hour) and 6-month (mean = 0 occurrences/hour) follow-up assessments | Quasi-experimental design makes it difficult to exclude other explanations (i.e., unidentified variables) for reduction in aggression (i.e., time-varying confounding) Unblinded outcome assessors |
| Smith & Coleman (1986)87 | Autism (DSM-III19) Moderate ID (IQ = 52) 26 y.o. man |
Aggressive behavior (hitting others, destroying property) in job setting | A-B (quasi-experimental with extended follow-up) | Subject received report card: Rated each hour on relevant job-appropriate behaviors (e.g., no hitting or kicking people, no property destruction), with subject earning 1 or 0 for each report card item each hour If all points earned during week, “successful week meeting” held with his favorite staff members |
Substantial reduction in aggressive behavior: During baseline period (weeks 1 to 7), subject earned average of 28 points; during first week of treatment, increased to 48 points; by week 22, began to regularly earn maximum number of 52 points |
Presence of full-time, trained counselor in work environment may be required to maintain treatment gains Cannot exclude time-varying confounding Outcome assessors not identified |
| McNally et al. (1988)88 | Autism (criteria unspecified) Severe ID 24 y.o. woman |
Aggressive behavior (kicking others), polydipsia | A-B | DRO schedule: At 30-minute assessment intervals, subject received tangible reinforcers (e.g., gum, candy, mustard, absence of work activity) for choosing to refuse water |
Substantial reduction in frequency of aggressive behaviors beginning at 4 weeks and maintained at 29-week follow-up, coinciding with reduction in polydipsic behavior (which was thought to be driving aggression due to frustration at redirection) | Due to A-B design, difficult to determine whether improvement in aggression due to intervention versus other effects associated with passage of time (i.e. time-varying confounding) Outcome assessors not identified |
| Cohen et al. (1991)89 | Pervasive developmental disorder (DSM-III-R20) Severe ID (Stanford-Binet IQ = 28) Fragile X syndrome 32 y.o. man |
Aggression toward others, property destruction, self-injurious behavior | A-B-A | Propranolol LA at dose of 80–320 mg daily over 11 weeks, preceded and followed by 2-week and 11-week placebo periods, respectively | Reduction in frequency of aggressive incidents, declining from baseline average rate of 1.7 events per week, and increasing posttreatment to average of 1.33 incidents per week when subject was returned to placebo | Because study focused on subject with fragile X syndrome, may have limited generalizability to adults with ASD without this genetic condition Did not control for possible synergistic effect of haloperidol + propranolol |
| Allison et al. (1991)90 | Autistic disorder (DSM-III-R20) Severe ID 24 y.o. man |
Grabbing, hitting, kicking, scratching, biting others in an intermediate care facility | Modified A-B-A-B | Physical exercise (consisting of jogging resulting in heart rate elevations to 60%–80% of maximum) for 20 minutes daily over 14 days compared to 14-day periods of no intervention | Exercise decreased aggressive behaviors by 68% Exercise alone more effective than combination of exercise and lorazepam in reducing aggression |
Optimal exercise frequency unclear Did not control for fatigue as possible confounding factor in reducing aggression Staff needed to be present to conduct exercise sessions safely Unblinded outcome assessors |
| Wong et al. (1991)91 | Autistic disorder (DSM-III-R20) Moderate ID 31 y.o. man |
Poking, hitting, kicking others in state mental hospital; forcefully slapping own head (required 1:1 continuous observation and frequent application of seclusion or restraints) | A-B (quasi-experimental with extended follow-up) | DRO schedule: Reinforcement (e.g., candy) provided following certain interval of time during which target behavior (aggression) did not occur; beginning with short DRO intervals, gradually lengthening such intervals to encourage longer periods of appropriate behavior |
Dramatic reduction in aggressive behavior and need for physical restraints (restraint use decreased from 42 incidents during first 24 days to no restraint use between days 200 and 300) | Quasi-experimental design makes it difficult to exclude medication effects or changes in staff behavior as alternate explanations for results (i.e. time-varying confounding) Unblinded outcome assessors |
| Hittner (1994)92 | Autistic disorder (DSM-III-R20) Severe ID (full scale IQ = 32) 25 y.o. man |
Aggression toward staff (including object throwing and table flipping), property destruction | A-B (quasi-experimental, simple interrupted time series) | Imipramine (150 mg/day) + DRA-O for 5 months | Substantial reduction in frequency of aggressive behavior, along with improvements in anxiety and depressed mood | Because of need to apprise all clinical personnel of medication changes and side effects, was not possible to keep staff “blind” to treatment protocol; hence, expectancy effects may have influenced data collection Because of quasi-experimental (simple interrupted time series) design, alternate hypotheses for results (e.g., maturation) could not be discounted (i.e., time-varying confounding) |
| Kennedy (1994)93 | Autism (DSM-III19) Moderate ID 20 y.o. man |
Grabbing others during demand situations and alterations in scheduling; biting self | A-B-A | Altering antecedent conditions, specifically provision of social comments by instructor (in addition to task demands): In first phase, task demands related to increased levels of problem behavior, and instructor social comments related to increased levels of positive social affect In second phase, low frequencies of task demands were interspersed with high frequencies of social comments, with task demands then faded in across sessions In third phase, task demands introduced in same manner as first phase |
Reduction in aggressive behavior: In third phase, task demands no longer associated with problem behavior (even in absence of social comments), suggesting that manipulating antecedent events can alter effects of task demands on aggressive behavior |
Could not exclude negative reinforcement extinction (in which problem behavior is reduced by repeatedly presenting a task demand but not allowing student to escape via problem behavior) or effects of fading alone as explanation for reduction in aggression (i.e., time-varying confounding) Unblinded outcome assessors |
| Reese et al. (1998)94 | Autistic disorder (DSM-III19) Moderate to severe ID 26 y.o. man |
Hitting, kicking, throwing objects, making verbal and physical threats | Reversal design examining effects of different DRO intervals across environmental contexts on rates of aggressive behavior | Combination of DRO procedure, token fines, and prompted relaxation over 5-day periods across various contexts (e.g., individual instruction, leisure time, house jobs) | Initial reduction in aggressive behavior dependent on choosing shorter DRO interval, with shorter DRO intervals more effective during activities in which baseline aggression rates were high (e.g., house jobs) Once shorter DRO intervals successful in reducing aggressive behavior, longer DRO intervals effective at maintaining reductions, for up to 6 months |
Generalization to community settings with fewer (or no) staff may be difficult Unblinded outcome assessors |
| Adelinis & Hagopian (1999)95 | Autistic disorder (DSM-IV21) Moderate ID 27 y.o. man |
Hitting, biting, kicking, pulling hair of others | A-B-A-B | Interrupting aggressive behaviors with “do” request (e.g., “Sit in a chair”) as opposed to “don’t” request (e.g., “Don’t lie on the floor”) | Substantial reduction in occurrence of aggression, with “do” requests provided during 4 10-minute sessions | Specific mechanism responsible for maintaining aggressive behavior unclear; for example, was aggression functionally related to contingent access to interrupted activity (positive reinforcement), contingent termination of “don’t” requests (negative reinforcement), or combination of both Unblinded outcome assessors |
| Kaplan et al. (2006)96 | Subject 1: Autistic disorder (criteria unspecified) Profound ID 52 y.o. man |
Verbal and physical aggression (not specified) | A-B-A | Occupational therapy using Snoezelen (multisensory environment) approach: Each subject participated in several sessions of occupational therapy using Snoezelen approach (30 minutes twice weekly), followed by several non-Snoezelen occupational therapy sessions, followed by return to several Snoezelen occupational therapy sessions |
Slight but noticeable reduction in frequency of aggressive incidents in days following Snoezelen sessions compared with frequencies observed during baseline and non-Snoezelen phases, suggesting that multisensory environment approach may have carryover effects in treating aggressive behavior for some days following treatment sessions (both subjects) | Small number of subjects Limited range of functional bases for problem behaviors (e.g., escape and tangible reinforcement); unclear how intervention would affect individuals with, for example, attention as functional basis for aggression |
| Subject 2: Autistic disorder (criteria unspecified) Profound ID 47 y.o. man |
Biting others | |||||
| McKee et al. (2007)97 | Subject 1: Autistic disorder (criteria unspecified) Moderate ID 31 y.o. man |
Assaulting staff and co-patients, throwing objects (furniture), hitting windows | A-B-A-B | Access to multisensory environment (Snoezelen room) for 28 days, followed by withholding access to Snoezelen room, followed by access again for 28 days | Snoezelen room associated with no clear effect on aggressive behavior, although trend toward more prosocial behavior (e.g., making eye contact, assisting staff, shaking hands) following Snoezelen intervention | Small number of subjects One subject spent only 30 minutes (as opposed to 45 minutes for other 2 subjects) in Snoezelen room each session Stimulus preference screening (finding out what elements of Snoezelen room most pleasurable and suitable for each subject and customizing sessions to maximize those elements) not done; such efforts may have increased carryover to non-Snoezelen environment Unblinded outcome assessors |
| Subject 2: Autistic disorder (criteria unspecified) Moderate ID 32 y.o. man |
Assaulting staff and co-patients, spitting | A-B-A-B | Access to multisensory environment (Snoezelen room) for 28 days, followed by withholding access to Snoezelen room, followed by access again for 28 days | Snoezelen room associated with increase in aggressive behavior, although trend toward more prosocial behavior (e.g., making eye contact, assisting staff, shaking hands) following Snoezelen intervention | ||
| Subject 3: Autistic disorder (criteria unspecified) Moderate ID 28 y.o. man |
Assaulting staff and co-patients, throwing objects | A-B-A-B | Access to multisensory environment (Snoezelen room) for 28 days, followed by withholding access to Snoezelen room, followed by access again for 28 days | Snoezelen room associated with no clear effect on aggressive behavior, although trend toward more prosocial behavior (e.g., making eye contact, assisting staff, shaking hands) following Snoezelen intervention | ||
| McClean et al. (2007)56 | Autistic disorder (criteria unspecified) Likely ID (conversed using repetitive phrases of up to 6 words; could carry out 1-step requests) 22 y.o. man |
Punching, slapping, kicking, pulling hair of others | A-B | Positive behavior support: Activity sampling; picture sequencing to improve predictability of daily events; reduction of unnecessary speech; offering requests using visual, 2-way choice format; escape training (e.g., prompting escape to room and prompting verbal communication “Too noisy”); antecedent control procedures (e.g., turning off television or radio after exiting room and removing unnecessary demands) |
Reduction in frequency of aggressive behaviors to near-zero levels within first 2 months, with sustained improvement over 24 months | As positive behavioral support is multi-element, not possible to isolate effect of individual interventions, account for contribution of nonspecific therapeutic factors (e.g., staff-client rapport), or separate effects of behavioral interventions from effects of range of support systems (i.e., time-varying confounding) Unclear if outcome assessors blinded |
| Flood et al. (2010)98 | Autistic disorder (unspecified criteria) ID (unspecified severity; nonverbal subject) 21 y.o. man |
Hitting, kicking, scratching, biting, grabbing; throwing objects at staff or peers; biting self to point of tissue damage on hands and arms | Reversal design examining effects of six different foods on aggressive behavior | Dietary intervention: 6 different foods were sequentially added and removed from diet to determine impact on aggressive behavior |
No notable change in aggressive or self-injurious behavior (in either positive or negative direction) | Staff responsible for recording problem behaviors also prepared subject’s meals during food evaluation phases and therefore were not blind to food conditions |
| McClean & Grey (2012)57 | Autistic disorder (DSM-IV21) Severe ID 2 men (21 y.o and 23 y.o.) |
Punching, kicking, hair pulling | A-B (quasi-experimental, multiple baseline across individuals design with extended follow-up) | Positive behavioral support-based, five-intervention sequence: Low arousal intervention, rapport building, visual scheduling, functionally equivalent skills teaching, and differential reinforcement strategies |
Substantial reductions in aggressive behavior during low-arousal intervention phase, with further reductions noted during rapport-building and subsequent intervention phases; intervention gains maintained at 76, 104, and 152 weeks | Concomitant interventions with unknown effect occurred at most intervention phases—for example, access to certain foods (time-varying confounding) Order of interventions did not vary; therefore, cannot exclude order effects on outcomes Unclear if outcome assessors blinded |
| Guercio & Cormier (2015)99 | ASD (DSM-51) 23 y.o. man |
Aggressive behavior, self-injury, property destruction whenever prompted to ride in van to day program | A-B-A-B | Task analysis/forward-chaining approach combined with prompt stimulus fading: Specifically, task analysis used to construct series of 10 steps for transporting subject to day program; forward-chaining approach then used, in which completion of successive steps in transport rewarded by providing subject viewing time of favorite video Fading consisted of gradual reduction in number of staff (with whom subject was comfortable) joining subject in van on transport to point that only 1 staff needed for ride |
Aggressive incidents decreased to zero during van rides, with only 1 staff required for ride | While task analysis/chaining and prompt fading were effective in teaching new behavior, unable to determine contributions of each separate intervention Unblinded outcome assessors |
ASD, autism spectrum disorder; DRA-O, Differential Reinforcement of Alternative and Other Appropriate Behavior; DRO, Differential Reinforcement of Other Behavior; DSM, Diagnostic and Statistical Manual of Mental Disorders; ID, intellectual disability; IQ, intelligence quotient; y.o., year old.