IDD-MH Prescriber Guidelines

IDD-MH Prescriber Guidelines

Funded by the WITH Foundation

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Anxiety Disorders

L. Jarrett Barnhill, MD, DFAPA, FAACAP

This section provides a brief overview of the adjunctive role for psychotropic drugs in the treatment of Anxiety Disorders in individuals with Intellectual and Developmental Disabilities (IDD) and Autism Spectrum Disorders (ASD). In this context, pharmacotherapy is part of a comprehensive treatment plan, not a stand-alone intervention.

From Anxiety to Anxiety Disorders

Anxiety represents a spectrum of emotional, somatic, and cognitive responses to both external and internal threats. The core features of anxiety arise from the basic neurobiology of fear (flight, fight, or freeze reactions) and fear-conditioned process that include generalization, sensitization, and resistance to extinction. At higher cortical levels, more complex neurocognitive processes generate anticipatory anxiety, agoraphobia, avoidance in response to perceived social disapproval, skill deficits in problem solving, intolerance of uncertainty, and anticipation of future threats.

Pathological anxiety is a step beyond developmental anxiety. It is anxiety that morphs out of the effects of trauma experiences, early loss, family chaos, and significant skill/problem solving deficits. Pathological anxiety usually presents as both internalizing and externalizing signs and symptoms that do not meet the full criteria for anxiety disorders. In at risk children, it may be a marker for prodromal or subsyndromal forms of anxiety disorders. An imbalance between genetic risk, life stressors and compromised resilience contribute to its progress towards full syndrome anxiety disorder.   

The diagnosis of Anxiety Disorders (AD) requires meeting current diagnostic criteria. The DSM-51 and DM-ID-22 include Specific Phobias, Separation Anxiety, Selective Mutism, Panic, Social Anxiety, Agoraphobia, Generalized Anxiety, Specified and Unspecified Anxiety Disorders, as well as Anxiety Disorder due to Another Medical Disorder. Specific ADs are frequently comorbid multiple psychiatric disorders in which they accentuate their negative impact on quality of life, intensify emotional distress and suffering, contribute to secondary depression and complicate treatment outcomes.

ADs are the most common psychiatric disorders among individuals with IDD. The higher prevalence rates for anxiety reflect an imbalance between resilience, negative life experiences (including trauma) and other susceptibility factors. The prevalence rates for ADs are influenced by diagnostic uncertainty secondary to cognitive and communication deficits, misinterpretation of baseline exaggeration data, and diagnostic overshadowing. Severe/profound disabilities can also interfere with our ability to distinguish AD subtypes. For many with severe/profound IDD, Unspecified AD (overlapping trauma or adjustment disorder), AD due to Another Medical Disorder, and Generalized Anxiety Disorders are about as specific as can be determined.

1American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders (5th ed.). Washington, DC: American Psychiatric Association, 2013.

2 Fletcher RJ, Barnhill J, Cooper S-A (Eds). Diagnostic Manual-Intellectual Disability 2: A Textbook of Diagnosis of Mental Disorders in Persons with Intellectual Disability. Kingston, NY: NADD Press; 2017.




Treatment: How Do We Help the Fly Get out of the Bottle?

This vignette reinforces two issues. First, the diagnosis and treatment of Anxiety Disorders requires a longitudinal, systemic/ecological perspective as clinical status may change over time. Secondly, the potential for diagnostic overshadowing of disorders can represent a two-way street, and that AD, neurodevelopmental, medical, and/or neurological disorders are not an either/or problem. Focusing exclusively on one or the other can backfire. These caveats support the concept that diagnoses are working hypotheses, not written in stone.

Current best practices trend toward Cognitive Behavior Therapy (CBT), Dialectical Behavior Therapy (DBT), Positive Psychology/Interactive Behavior Therapy (PP/IBT), exposure therapy, and other psychological interventions as preferred frontline treatments.  Meta-analytic studies report similar response rates with frontline psychotropic medications (SSRIs and SNRIs). Combining therapies is a practical solution, but the evidence related to managing treatment non-responders suggests that this may be case-by-case decision. Despite this caveat, psycho/ecological therapies are useful for bracketing pharmacotherapies – used prior to assess need, and as a tool in reduction/elimination strategies as a means of relapse prevention.

Meta-analytic studies also suggest that psychotropic drugs can be organized into algorithmic hierarchies (see Table 1). Most pharmacotherapy algorithms begin with SSRI’s and SNRI’s as frontline treatments. Predictors of moving onto second, third and augmentation strategies usually boil down to a lack of response or intolerance. If the drug is not effective and diagnostic and pharmacokinetic parameters are not contributory, then interclass exchanges within Tier 1 and/or moving to the next tier, or augmentation is next. If a drug is not tolerated, then switching to alternative classes of medications is prudent. 

The second and third treatment tiers are frequently older treatments or those without sufficient research support. As outlined in the table, there is a variety of drug classes and possible mechanisms of action in treatments; for example, older treatments (tricyclics, benzodiazepines) as a replacement for ineffective SSRI/SNRIs. The third-tier treatments are consistent with a high degree of variability within AD drugs like pregabalin, buspirone, beta blockers, multiple anticonvulsants and second-generation antipsychotics. They are usually Tier 3 interventions but can be preferentially effective in General Anxiety and Social Anxiety Disorders (performance specifier). The need for second and third tier treatments reinforces the biopsychosocial complexity of ADs in people with IDD.

Table 1. Categories of Anxiety Disorders


Anxiety Disorder

Fear related

Panic disorder; Social Anxiety (performance); Specific Phobias; Separation Anxiety

Anxious anticipation of threat

Agoraphobia; Selective Mutism

Excessive worry and misery

Generalized Anxiety Disorders; Mood-Anxiety Disorders

Anxiety Disorder due to another medical condition, unspecified and anxiety/trauma anxieties may fall in each of the categories above.

Table 2. Consensus Treatment Algorithm-Anxiety Disorders

Tier 1

  • 1st and 2nd generation SSRIs and SNRIs
  • Short term benzodiazepines
  • Beta-blockers (social anxiety-performance related)

Treatment non-responders: review diagnoses and current team-based treatment plan

Tier 2

  • Pregabalin
  • Benzodiazepine and other GABA-Calcium channel mediating treatments
  • 3rd generation SSRI (Votioxine is most popular)
  • Tricyclic Antidepressants

Treatment resistance: define tier level and comfort zone. Do not hesitate to seek second opinions/consults. It is useful to refer for a second opinion once.

Tier 3

  • Reversible and standard MAO-A and B Inhibitors
  • Valproic acid and other anticonvulsants
  • 2nd and 3rd generation antipsychotic augmentation
  • Buspirone (Generalized anxiety)
  • Beta-blockers
  • TMS and somatic therapies
  • Alternative treatments


This review provided an overview of the role of pharmacotherapies as adjuncts in the treatment of AD in the context of IDD. SSRI’s, SNRIs along with several psychotherapeutic interventions are generally front-line, trans-diagnostic treatments that are effective across the spectrum of anxiety disorders (including comorbid or externalizing variants).

However, there are exceptions.  In general, “starting low and going slow” is the most sensible approach but even at “therapeutic ranges,” prescribers can struggle with low remission, high relapse rates, and substantial numbers of non-responders to both psychotherapy and pharmacotherapies. One should remain cognizant that psychotropic drugs are adjunctive treatments, and that their true values lies in ecologically-based interventions.


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