Undetected ADHD May Explain Poor SSRI Response in Depression

Pam Harrison

April 14, 2016

PHILADELPHIA — Adults who fail to respond to antidepressant therapy may have underlying attention-deficit/hyperactivity disorder (ADHD) and not treatment-resistant depression, as is often assumed, new research suggests.

"ADHD is relatively new as a diagnosis made in adulthood, so when people present with symptoms of depression, physicians typically won't ask any further questions about their history or assess for ADHD. Instead, they will prescribe them a selective serotonin reuptake inhibitor [SSRI]," Tia Sternat, START Clinic for Mood and Anxiety Disorders, in Canada, told Medscape Medical News.

"But depressed patients with ADHD don't typically respond to SSRIs because of the psychopathology involved — you have to activate the catecholaminergic system to treat ADHD — so they come in saying, 'I feel better, but I'm not happy; I'm tired, I'm anxious, I'm having trouble with attention,' and what you are seeing are the adult signs of ADHD coming through," she added.

"So physicians need to screen for premorbid conditions, including ADHD, before making the diagnosis of treatment-resistant depression."

The research was presented here at the Anxiety and Depression Association of America (ADAA) Conference 2016.

ADHD Common

Investigators collected data from 123 referrals to a single tertiary-care mood and anxiety clinic. The mean age of patients was 39.8 years; ages ranged from 17 to 71 years. A total of 105 patients were included in the final analysis. Patients referred for ADHD assessment were excluded.

The intake diagnosis was performed using the Mini International Neuropsychiatric Interview Plus 5.0.0, and the attending psychiatrist undertook a semistructured interview with each referred patient.

Results indicated that undetected ADHD was present in more than 28% of patients referred to the tertiary-care clinic for assessment of mood and anxiety disorders.

Significant factors that were predictive of the presence of undetected ADHD among patients referred to the clinic for mood and anxiety assessment included the number of diagnoses a patient had received (P = 0.004), the patient's medication history (P = .001), and the number of SSRIs the patient had received (P = .026).

Significant factors that were predictive of the presence of previously undiagnosed ADHD for patients referred to the clinic for treatment-resistant depression again included the number of diagnosis the patient had received (P = .006); the number of failed medications at intake (P = .005); past SSRI failure (P = .003); and the presence of social anxiety disorder (P = .006).

Catecholamine Stimulation

"If patients are on an antidepressant, we're not suggesting that you necessarily take them off the medication if they are doing well, but you would need to add something that works on the catecholamine system to resolve the ADHD symptoms," Sternat noted.

This could include a catecholaminergic agonist, such as a noradrenalin-dopamine reuptake inhibitor or psychostimulant, she added.

Sternat also believes physicians need to treat patients who have both depression and ADHD on a patient-to-patient basis, depending on which constellation of symptoms is having the biggest impact on their life.

Anhedonia, for example, is common in both ADHD and in some cases of depression. Patients with anhedonia require a dopamine-promoting agent to overcome the symptoms of chronic or lifelong anhedonia.

"Some people still believe that ADHD is a childhood disorder and that patients will outgrow ADHD at the age of 18, when the brain matures," Sternat observed.

"But symptoms of ADHD morph as people age, and what happens is that they end up being diagnosed with treatment-resistant depression or anxiety," she said.

Sternat added that the inclusion of the diagnosis of adult ADHD in the DSM-5 gives credence to the fact that children do not "outgrow" ADHD and that physicians need to look for it in the setting of treatment-resistant mood disorders.

Tia Sternat has disclosed no relevant financial relationships.

Anxiety and Depression Association of America (ADAA) Conference 2016: Abstract S2-10, presented April 2, 2016.


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