Depressive Disorders

Jennifer McLaren, MD

This section provides a brief overview of Depressive Disorders in individuals with Intellectual and Developmental Disabilities (IDD) and Autism Spectrum Disorders (ASD). Depressive Disorders are common among individuals with IDD, with lifetime prevalence rates of 37%.1  Common antecedents for depression in individuals with IDD include personal loss (e.g., caregiver, friend, staff), isolation, marginalization, meaninglessness, lack of autonomy, trauma, bullying, victimization, or other adverse experiences. It is important to ask about these losses as it should impact the therapeutic intervention chosen.

Assessment

The core features of Depressive Disorders are a depressed and/or irritable mood with a marked change from an individual’s baseline and impairment in functioning. The severity of an individual’s ID impacts the presentation of depression. Individuals with mild to moderate ID may report feeling sad or depressed, making depression easier to recognize. Individuals with a more significant intellectual impairment may not be able to verbalize their internal feelings, making a depression diagnosis more nuanced.  For all individuals, observation of presentation and collateral information are key. 

The diagnosis of Depressive Disorders requires meeting current diagnostic criteria for one of the following: Disruptive Mood Dysregulation Disorder, Major Depressive Disorder, Persistent Depressive Disorder, Pre-menstrual Dysphoric Disorder, Other Specified and Unspecified Depressive Disorders, and Depressive Disorder Due to Another Medical Condition. These disorders are frequently comorbid with anxiety disorders. Consider utilizing a standardized rating scale when assessing and treating depression such as the PHQ-9. Adaptations to the PHQ-92 have been made for individuals with IDD.

For moderate to severe depression consider a combination of therapy plus antidepressants. There is a lack of research on psychopharmacologic treatments for individuals with depression and IDD. The psychotropic medications used to treat depression in typically developing individuals are utilized for individuals with IDD. It is important to start antidepressants at a low dose and slowly titrate and consider comorbid medical issues and drug-to-drug interactions. Consider utilizing a SSRI as the initial pharmacologic treatment based on their efficacy and tolerability (Figure 1). If an SSRI is not appropriate, then consider serotonin-norepinephrine reuptake inhibitors, atypical antidepressants, and serotonin modulators (Figure 1). Studies show the efficacy of the various antidepressants as comparable across and within the different classes for both acute and maintenance treatment. The selection of an antidepressant is based on the following: symptoms, comorbid diagnosis, safety, side effect profile, drug-to-drug interaction, patient preference, cost, first-degree relative with a history of a positive response to an antidepressant, and patient’s previous response to medications.

Some side effects to consider when selecting an antidepressant include the following:

  • Citalopram: increase in irritability for individuals with ASD; QT prolongation
  • Sertraline: higher rates of diarrhea
  • Venlafaxine: more nausea and vomiting
  • Bupropion: less sexual dysfunction; contraindicated in eating disorders
  • Mirtazapine: greater weight gain

Tricyclic antidepressants and monoamine oxidase inhibitors are typically not utilized as initial treatment for depression given their more serious side effect profile and elevated risk with overdose. 

After initiation of an antidepressant, improvement can be seen in 2-4 weeks. If the individual is not improving and tolerating the antidepressant, then titrate the antidepressant in stepwise increments as tolerated up to lowest effective dose.

1 American Psychiatric Association. Practice Guidelines for the Treatment of Patients with Major Depressive Disorder. Washington DC: American Psychiatric Association, 2010.

2 Breen J. Adapting the GAD-7 and PHQ-9 Clinical Measures for People with Learning Disabilities [PhD thesis]. Royal Holloway, University of London; 2017.

Key Components in Assessing Depression in Individuals with ID and ASD

Comprehensive history with collateral information, including behavioral observations from caregivers, residential staff, day staff, etc.

  • Good understanding of individual’s baseline functioning and change from baseline
    • What does the individual look like when they are doing well? 
    • When did they last appear that way? 
  • Symptoms of mania or hypomania include a persistently elevated, expansive or irritable mood with the following symptoms:
    • Depressed mood and/or irritable mood
    • Loss of interest or pleasure
    • Change in appetite or weight
    • Insomnia or hypersomnia
    • Psychomotor agitation or retardation
    • Fatigue or loss of energy
    • Feelings of worthlessness or guilt (individuals with severe/profound intellectual disability do not have cognitive capacity to display this symptom)
    • Decrease in concentration
    • Recurrent thoughts of death or suicidal ideation or attempts
  • Timeline and Severity
    • When did the patient begin having symptoms?
    • On a scale of 0-10, how severe are the symptoms with 10 being the worst?
    • Previous episodes of mania and depression and response to treatment
  • Assess for episodes of mania or hypomania to rule out bipolar disorder
  • Comorbid substance use/abuse/dependence
  • Assess for psychosocial stressors and abuse
  • Family history of mental health issues and suicide attempts or completions

Physical examination: Assess for illnesses can be associated with depression (e.g., Hypothyroidism, Epilepsy, Stroke, Anemia).

Review individual’s medication list. Assess if medications are causing/contributing to depression.

  • Ask about complementary and alternative medications.
  • Some classes of medication can cause depression (e.g., cardiovascular drugs, chemotherapeutics, antiparkinsonian, anti-infective and antiretroviral agents, anticonvulsants, hormones, antihistamines and sedatives).

Mental Status Examination: Assess suicidality and homicidality, psychotic symptoms, catatonic symptoms, and future orientation.

Labs to consider: Thyroid stimulating hormone (TSH), complete blood count (CBC), vitamin D level, liver function tests (LFTs), renal function tests

Treatment resistance

For individuals not showing improvement with antidepressant treatment, consider re-evaluating their diagnosis and compliance with treatment. Switching antidepressants should be considered if symptoms fail to improve after a 6 to 12-week medication trial at a therapeutic dose (See Figure 1). If the individual shows a partial response to treatment, consider augmenting the initial antidepressant with second-generation antipsychotics (aripiprazole, quetiapine, and risperidone), lithium, or other antidepressants. Risks and harms of adding additional medications must be carefully considered. After three adequate trials of antidepressants, if the individual continues to have significant symptoms of depression, consider neurostimulation such as repetitive transcranial magnetic stimulation (rTMS) and then electroconvulsive therapy (ECT). ECT should only be utilized when symptoms are severe, refractory to medication treatment, or when medication options run out.

Figure 1. Consensus treatment psychotropic algorithm – Depressive Disorders

consensus treatment psychotropic algorithm

* Combination Medication Treatment with medications that complement each other such as Buproprion plus SSRI, TCA plus SSRI

Comorbid Treatment

  • For individuals with severe suicidality or malnutrition secondary to depression and food refusal: consider electroconvulsive therapy
  • For individuals with psychotic symptoms: add an antipsychotic to antidepressant treatment
  • For individuals with catatonic features due to depression: add a benzodiazepine to antidepressant treatment

Case Vignette

Mr. F is a 28-year-old male with mild ID. At his baseline, he is friendly, funny and enjoys spending time with others. He has been living with a caregiver for the past 5 years. Mr. F’s caregiver scheduled the initial appointment due to a concern that Mr. F does not want to get out of bed in the morning.

Upon interview you learn, Mr. F is pacing more than unusual, no longer engages in his preferred activities, needs more encouragement to do things, is irritable, and makes statements that he is bad, he wishes he was dead or not here. While you didn’t learn about this initially, through additional inquiry about recent stressors, you also learned that there was a recent change in staffing at his day program. He has intermittent tearfulness, which is new. Mr. F’s biological family has a history of schizophrenia, depression and anxiety.

You diagnose Mr. F with a major depressive disorder. The PHQ-9 completed by Mr. F’s caregiver is consistent with depression. Mr. F is connected to a therapist, however, there is a wait of several weeks to start. In the meantime, Mr. F’s caregiver is encouraged to purposefully schedule enjoyable and meaningful activities in which to engage Mr. F. You model how to validate the feelings of loss Mr. F is experiencing. Mr. F is started on an SSRI to treat depression. Mr. F begins modified CBT several weeks later. His therapist reviews his previous neuropsychological assessments to target Mr. F’s therapy to his cognitive strengths. Mr. F’s depression resolves in several weeks with combination treatment of SSRI, modified CBT, encouraged engagement, and validation of his feelings of losing a preferred staff. He remains on his SSRI for 1 year, and it is slowly tapered with no re-emergence of depressive symptoms.

References

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

American Psychiatric Association. Practice Guideline for the Treatment of Patients with Major Depressive Disorder. Washington DC: American Psychiatric Association, 2010.

Breen J. Adapting the GAD-7 and PHQ-9 Clinical Measures for People with Learning Disabilities [PhD Thesis]. Royal Holloway, University of London; 2017.

Constantino JN, Strom S, Bunis M, et al. Toward actionable practice parameters for "dual diagnosis": Principles of assessment and management for co-occurring psychiatric and intellectual/developmental disability. Curr Psychiatry Rep. 2020; 22(9).

Cooper SA, Smiley E, Allan L, et al. Incidence of unipolar and bipolar depression, and mania in adults with intellectual disabilities: prospective cohort study. Br J Psychiatry. 2018; 212:295-300.

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National Collaborating Centre for Mental Health (UK). Depression: The Treatment and Management of Depression in Adults (Updated Edition). Leicester, UK: British Psychological Society; 2010.

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.

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