Can Antidepressants Be Used To Treat ADHD?
The general answer is no. Especially serotonin-specific antidepressants like Zoloft, Lexapro or Prozac (fluoxetine) can exacerbate symptoms of ADHD, leading to problems in decision-making, learning and cognitive flexibility. Noradrenaline-targeting antidepressants like atomoxetine can be effective second-line treatment to manage co-morbid conditions in ADHD.
Let's understand the reasons in more detail.
What is ADHD?
ADHD is the common abbreviation for Attention Deficit Hyperactivity Disorder. This is a type of neurodivergent disorder that arises in early childhood and is characterised by inattentiveness, hyperactivity and distractability [1].
Historically, ADHD has also included Attention Deficit Disorder (ADD), which was specific to children with attention problems rather than hyperactivity. In the newest Diagnostic and Statistical Manual (DSM-V), ADD and ADHD have been merged into a single DSM-V diagnosis of ADHD, encompassing sub-sections relating to attention and hyperactivity symptoms [2]. It is important to note that patients may present with one of these subtypes first and later experience other symptoms.
For a diagnosis of ADHD, according to the DSM-V, symptoms must be present before the age of 12 and persist for over six months [2]. More recently, adults have started to receive ADHD diagnosis [3]. This insurgence of adult ADHD is attributed to an increasing understanding of the disorder and our ability to help individuals manage ADHD using stimulants, antidepressants or lifestyle modification. Therefore, the ICD-11 does not specify an age before symptoms are first noticed [4].
Symptoms of ADHD
ADHD is characterised by hyperactivity, inattention and impulsivity, but what does this look like in daily practice?
Inattentive symptoms of ADHD [1]:
- Not listening when being spoken to or given instructions
- Rushing through tasks
- Missing details in work
- Avoiding or struggling to complete work that requires sustained attention
- Forgetting things, missing appointments or misplacing items
Hyperactivity symptoms of ADHD [1]:
- Talking out of order
- Climbing objects
- Constant fidgeting
Hyperactivity symptoms can be more challenging to identify in adults, as adults are generally better at controlling their physical activity [1].
ADHD can also cause a state known as ADHD Paralysis.
Many of these symptoms sound familiar, and everyone has likely experienced them. Therefore, it is critical to consult a medical professional if you find these persisting longer than six months and cause significant impairment to your tasks in at least two aspects of life (eg. family and relatives, work, personal life).
What Is The Prevalence of ADHD?
Many people incorrectly assume that ADHD is a novel diagnosis resulting from increasing social media use and the modern stimulating environment. This is not true. ADHD was first reported in the 18th century, although it was called differently. For example, in the 1930s, it was called 'minimal brain dysfunction'.
The prevalence of ADHD is, however, increasing. At present, UK national epidemiological centres estimate the prevalence of ADHD in children to be about 5% [5]. This is likely higher in the United States, where recognition and acceptance of the condition are higher [6].
About 60% of childhood ADHD cases persist until adulthood. Combined with new adult ADHD diagnoses, the prevalence of ADHD in adults is up to 7%, based on a study from 2021 [6].
ADHD is more prevalent in specific clinical populations, such as people who have pre-existing depression.
What Are Antidepressants?
Antidepressants are psychoactive substances that are used for the treatment of depression. They can be split into several groups. These are:
- Tricyclic antidepressants
- Serotonin noradrenalin reuptake inhibitors (SNRIs)
- Selective serotonin reuptake inhibitors (SSRIs)
For more information about how these work, I recommend diving into our earlier blog on antidepressants, including SSRIs, lexapro and Zoloft.
Can You Use SSRIs for ADHD Treatment?
SSRIs are a type of antidepressant that increase the availability of serotonin throughout the brain by reducing its re-uptake by neurons after it has been released. SSRIs have shown some effect in individuals with ADHD.
For example, the SSRI fluoxetine reduced the activation of frontal parts of the brain using a task where the reward was reversed, and the participants had to adapt their behaviour accordingly. In this study, the reduction in front of brain activity led the individuals with ADHD to perform worse on this task [7]. Therefore, SSRIs have a detrimental impact on ADHD symptoms and are not a suitable or recommended treatment for ADHD [8].
Can you use Zoloft for ADHD Treatment?
Zoloft is the brand name for sertraline, a type of SSRI [9]. Zoloft (sertraline) has been increasingly used for obsessive-compulsive disorder and panic attacks, as well as its first-line antidepressant properties [9].
ADHD has been treated by Zoloft (sertraline), but Zoloft (sertraline) has not been effective at reducing symptoms of ADHD. Zoloft (sertraline) has been effective at reducing symptoms of comorbid conditions, such as depression or anxiety.
In this study from 1996, using 10mg and 25mg of sertraline in adults and children improved symptoms of co-occurring depression but had no benefits for ADHD symptoms [6]. Furthermore, it is not advised to prescribe antidepressant medication to young children unless essential due to the number of neuro-developmental processes occurring at this life stage [10].
Can you use Lexapro for ADHD treatment?
Lexapro, the brand name for escitalopram, is a first-line treatment for major depression with lower side effects and a low risk of overdose. Lexapro has been approved for anxiety treatment in children over the age of 7, indicating Lexapro is tolerated in age groups similar to ADHD patients [11].
Nonetheless, there is no evidence supporting the use of Lexapro for ADHD symptom management and treatment. If patients with ADHD have a co-morbid diagnosis of depression, then Lexapro may help improve mood. Lexapro can also have a mild benefit for individuals with OCD-like impulsivity, which is one of the presentations of ADHD [12].
Can you use SSNRIs for ADHD treatment?
SSNRIs, or selective serotonin noradrenalin reuptake inhibitors, are a class of antidepressant drugs that increase the availability of serotonin and norepinephrine in the brain. Due to this, they have been associated with mood and cognitive improvements since norepinephrine has stimulatory effects on the body [13]. In ADHD, changes to the noradrenalin receptor have been found in areas of the brain responsible for attention [14], supporting the use of noradrenalin-targeting medication in ADHD.
Nonetheless, no direct evidence has been found for SSNRIs being used for ADHD treatment.
Atomoxetine for ADHD Treatment
A related class of drugs are selective noradrenalin reuptake inhibitors, which do not increase the abundance of serotonin, isolating their effects purely on noradrenaline. The evidence for SNRIs is more evident.
For example, atomoxetine is a first-line medication for ADHD treatment in both adults and children over the age of 5 [15]. Atomoxetine is only sporadically used for depression treatment, but may still be considered an antidepressant. Atomoxetine has been particularly effective at improving symptoms of comorbid disorders in ADHD, such as dyslexia, dysgraphia, tics or autistic symptoms [16].
Other Antidepressants for ADHD Treatment
Two other antidepressants can be used as non-stimulant treatments for ADHD.
Bupropion is an antidepressant for ADHD off-label treatment. This means that it has shown benefits in treating ADHD but is not yet a guideline-approved antidepressant for ADHD. Bupropion increases the availability of noradrenalin and dopamine in the brain [17]. A meta-analysis found that it improved symptoms of ADHD in adults without increasing side effects. Nonetheless, funding from companies that market bupropion could bias these findings [18]. Indeed, earlier unbiased studies found that bupropion could increase the severity of tics and cause rashes [8].
Venlafaxine is another antidepressant for ADHD off-label treatment. This antidepressant acts similarly to SSNRIs but primarily increases noradrenalin in the brain. The results of the effectiveness of venlafaxine are mixed. Some studies found that venlafaxine reduced ADHD symptoms, but placebo-controlled trials reported the reduction was not significantly different to taking a placebo for six weeks [19]. Therefore, although venlafaxine has preliminary evidence of reducing ADHD symptoms, these may not be directly caused by the medication's pharmacological properties.
What drugs can be used for ADHD Treatment?
Stimulant drugs are currently the first-line treatment for childhood and adult ADHD. Parent training and behaviour interventions are recommended in preschool children before prescribing medication, especially in countries like Germany [20].
Stimulants come in two forms - amphetamines and methylphenidate. Both drugs for ADHD are strictly regulated in the US and UK, which means they are only available on prescription.
Amphetamines and methylphenidate act on the dopamine system, increasing the availability of dopamine. Increased availability of dopamine and noradrenalin modulates excitatory and inhibitory neurotransmission throughout the brain and can improve cognitive processes.
Amphetamines for ADHD
Amphetamines were first marketed in tablet form in the 1930s under the name Benzedrine [16]. Its initial use was to help soldiers stay awake during WWII, and now, they are most effective at relieving symptoms of ADHD in both children and adults [21].
Amphetamines are widely available in the US but more tightly regulated in other parts of the world. For example, in many Asian countries, amphetamines are banned substances, even for ADHD treatment [16].
Methylphenidate for ADHD
Methylphenidate was first marketed as Ritalin in the 1950s [16]. It is the second most effective drug at alleviating symptoms of ADHD. Due to its availability in Europe, Australia, Canada and other countries, it is often the best available medication [21]. Methylphenidate drugs are especially recommended in children as they have fewer side effects than amphetamines [21].
Summary of Antidepressants for ADHD
In general, antidepressants should not be taken for ADHD. SSRI antidepressants, like Zoloft, Lexapro, or fluoxetine (Prozac), can in fac worsen symptoms of ADHD, causing problem with decision-making, learning, or cognitive flexibility. Noradrenaline-targeting antidepressants (SNRI), on the other hand, can indeed be effective second-line treatment to manage co-morbid conditions in ADHD. As always, make sure to monitor your symptoms and consult a medical professional before taking any medication or self-diagnosing, as these drugs used to treat ADHD are tightly controlled and addictive substances.