Antidepressant Drug Treatment in Child and Adolescent Psychiatry: Randomized Controlled Trials versus Naturalistic Studies
Robyn Cardy1, PS Reddy2*
1Centre for Neuroscience Studies, Department of Psychiatry,
Providence Care-MHS,Queen’s University, Canada
2Departmentof Psychiatry, Queen’s University Kingston, Ontario,
Canada
*Corresponding author: PS Reddy, Departmentof Psychiatry, Queen’s
University Kingston, Ontario, Canada.Tel: +13433330047;
Email: psreddy50@hotmail.com
Received Date: 23 March 2017; Accepted Date: 22 May, 2017; Published Date: 30 May, 2017
Citation: Cardy R, Reddy PS (2017) Antidepressant Drug Treatment in Child and Adolescent Psychiatry: Randomized Controlled Trials versus Naturalistic Studies. J Neurol Exp Neural Sci: JNNS-126. DOI: 10.29011/JNNS-126. 100026
1. Introduction
Since the late 1990s, there has been a
substantial increase in the use of antidepressant drug treatment in child and
adolescent psychiatric care [1].
Although regulatory warnings prompted in a decline in pediatric antidepressant
use from 2003 to 2005, their use has since rebounded [2].
And while most products have not been approved for use in this population,
off-label use of antidepressants is widespread practice [3].
Antidepressants, like all medications, warrant concerns over their efficacy,
tolerability, and safety in child and adolescent psychiatry. Generally,
antidepressants have several side effects, such as weight gain, fatigue, and
sexual dysfunction. However, the wide diversity of antidepressants support the
individualized selection of treatment, allowing clinicians to personalize
treatment for their pediatric patients based on psychiatric symptoms and
undesirability of certain side effects. The purpose of this review was to
investigate the classes of antidepressant medications, and their associated efficacy,
tolerability, and safety in pediatric psychiatry. A review of randomized
controlled trials and meta-analyses of antidepressant medications in pediatric
populations for the treatment of a range of psychiatric indications, such a
major depressive disorder, anxiety disorders, and obsessive compulsive
disorder, was conducted. A subsequent review of the available naturalistic
studies for antidepressants in this population was carried out. The latter
highlighted the paucity of studies available and the need for naturalistic
studies in diagnostically heterogeneous pediatric populations receiving
antidepressant drug treatment. Lastly, the common methodological and ethical
limitations of naturalistic studies was assessed and addressed. The aim of this
report was to emphasize the clinical significance of naturalistic studies and
to better inform the proposal of a naturalistic prospective study of
antidepressant medications in child and adolescent psychiatry.
2. Antidepressant Drug Treatment
2.1. Definition
The term “antidepressants” refers to a
chemically and pharmacologically heterogeneous class of psychopharmacological
agents originally prescribed to treat patients with depressive symptoms, but
are associated with use in a wide array of disorders today. These agents have
been successfully applied to the treatment of major Depressive Disorder (MDD),
anxiety disorders, Obsessive Compulsive Disorder (OCD), eating disorders,
mutism, and Attention Deficit/Hyperactivity Disorder (ADHD). Antidepressants
elevate pathologically depressed mood, may increase activity or diminish
psychomotor restlessness, and may lessen somatic and vegetative symptoms [4]. Antidepressants are associated with
several side effects, including weight gain, sexual dysfunction, and fatigue.
Although the mechanism of action of antidepressants is not yet fully
understood, most antidepressants primarily inhibit the neuronal reuptake of
monoamines (such as serotonin or noradrenaline) from the synapse. Generally, it
is recommended antidepressant therapy is continued for 4-6 months after
symptoms subside before the dose is reduced or discontinued [4].
Antidepressants are classified according
to their recognized biological sites and mechanisms of action: Selective
Serotonin Reuptake Inhibitors (SSRIs), Serotonin and Norepinephrine Reuptake
Inhibitors (SNRIs), Norepinephrine and Dopamine Reuptake Inhibitors (NDRIs),
Noradrenergic and Specific Serotonergic Antidepressants (NaSSAs), Tricyclic
Antidepressants (TCAs), and Monoamine Oxidase Inhibitors (MAOIs). Within each
class of antidepressants, there are a number of individual agents that differ
in their degree of neuronal inhibition, present varying efficacies,
tolerability, and safety, and pose distinctive potentials for drug
interactions. These side effects of antidepressant treatment can adversely
impact patients’ compliance and have the potential to influence treatment
outcome, morbidity and mortality [1]. It
is therefore imperative to quickly determine the most effective agent for a
given patient; fortunately, the multiplicity of antidepressant agents allows
clinicians to better individualize treatment for psychiatric disorders [1].
2.2.
Classification
2.2.1. SSRIs: This group of drugs,
including fluoxetine (Prozac), paroxetine (Paxil), fluvoxamine (Luvox),
citalopram (Celexa), escitalopram (Cipralex), and sertraline (Zoloft), is
usually the first choice for treatment of anxiety and depression problems [6]. SSRIs are typically
well tolerated drugs associated with less serious adverse events; common side
effects include headache, loss of appetite, nausea, diarrhea weight loss, dry
mouth, sweating, and disturbances of sexual function (Taurines et al.,
2014)[4].
2.2.2.
SNRIs : This class of medications
includes venlafaxine (Effexor), duloxetine (Cymbalta), and desvenlafaxine
(Pristiq). These drugs are typically used to treat depression, anxiety
problems, and chronic pain. Because of its efficacy observed in clinical trials
in adults, low side-effect profile and early onset of action, venlafaxine is
suggested as medication useful for use in children and adolescents [5].
2.2.3.
NDRIs : The medication available in this
class is bupropion (Wellbutrin, Zyban). Bupropion is often given forenergizing
effects, in combination with other antidepressants, in the treatment of
depression [4].
It is also used to treat Attention-Deficit/Hyperactivity (ADHD) disorder.
Common side effects are jitteriness and insomnia.
2.2.4. NaSSAs: The agent available in this class,
mirtazapine (Remeron), is the most sedating antidepressant, and is therefore
most appropriate for people who have insomnia or who are very anxious [6].
This medication also helps to stimulate appetite. Common side effects are
drowsiness and weight gain.
2.2.5.
TCAs : This older group of agents is the
most extensive of all antidepressant types, comprised of amitriptyline (Elavil),
maprotiline (Ludiomil), imipramine (Tofranil), desipramine (Norpramin),
nortiptyline (Novo-Nortriptyline) and clomipramine (Anafranil). Common side
effects include dry mouth, tremors, constipation, sedation, blurred vision
difficulty urinating, weight gain and dizziness. Additionally, because TCAs may
cause heart rhythm abnormalities, an Electrocardiogram (ECG) is recommended
before onset of treatment [6]. Moreover, overdose and intoxication of TCAs is
associated with fatal cardiac arrests [4].
Because these medications tend to have more severe side-effects than newer
antidepressant classes and they pose an elevated risk of intoxication [7], they are not often a first
choice for treatment. However, when other drugs do not provide relief from
severe depression, these agents may help.
2.2.6.
MAOIs : MAOIs, such as phenelzine (Nardil)
and tranylcypromine (Parnate), were the first class of antidepressants.
Although effective, MAOIs are often avoided because one must follow a special
diet to avoid hypertensive crises associated with the consumption of
tyramine-containing foods [4], such as aged cheeses and nuts. A newer MAOI,
moclobemide (Manerix), can be used without dietary restrictions; however, it
may not be as effective as other MAOIs. Common side effects include a change of
blood pressure when moving from a sitting to a standing position (orthostatic
hypertension), insomnia, swelling and weight gain [6].
3.
Randomized Controlled Trials of Antidepressant Drug Treatment in Children and
Adolescents
3.1. SSRIs
In child and adolescent psychiatry,
SSRIs have become the primary choice for the pharmacological treatment of
anxiety and depressive disorders [4,7-10]
and the use of SSRIs
in the clinical treatment has become increasingly common[11,12]. A
Canadian Institute of Health Research (CIHR) funded study in Quebec revealed
that SSRIs were the most frequently dispensed (58.8%) antidepressant products
among adolescents [3].
This trend is in large part due to their comparatively good efficacy and
tolerability, giving them a favourable benefit-risk profile for pediatric use [4,13,14].
Several controlled studies have indicated that SSRIs are superior to placebo in
child and adolescent psychiatric care. Results from a meta-analysis, which
included 18 controlled and 23 open trials, suggested a significant benefit of
SSRIs over placebo in the treatment of pediatric depression [15]. In
the treatment of anxiety disorders (generalized anxiety, social phobia, and
separation anxiety), SSRIs have also been shown to reduce symptoms [16,17].
However, in 2004, the United States Food
and Drug Administration (FDA) issued a black box warning for antidepressant
treatment in children and adolescents. Consequently, Bridge and colleagues
(2007)[13] conducted a
meta-analysis assessing the use of antidepressants across the indications of
depression, anxiety disorders, and OCD in pediatric populations. The review,
which included 27 prospective Randomized Controlled Trials (RCTs),estimated
suicide risk associated with SSRIs in the treatment of children and adolescents
at less than 1% [13]. A more recent
meta-analysis maintained no elevated risk for suicidal thoughts or actions in
pediatric antidepressant treatment with fluoxetine, citalopram, sertraline, or
paroxetine [18].
Nevertheless, a subsequent review by Sparks and Duncan (2013)[2]posits recent investigations on the safety
and efficacy of antidepressants contain significant confounds that discredit
their findings, and suggests firstline prescription of antidepressants for the
pediatric population is not advisable and further investigations are warranted.
The most studied SSRI agent in the realm
of child and adolescent psychiatry RCTs is fluoxetine. In the treatment of
depressive disorder, fluoxetine [8,18-22] sertraline [23,24],
citalopram [25],
escitalopram [26,27], and
paroxetine [28] have
all demonstrated superiority over placebo for children and adolescents.
Although, results have been inconsistent for some agents. Results of a 2006 RCT
indicated that for depression, escitalopram was only beneficial in the
treatment of adolescent populations, but showed no superiority over placebo
when younger children were included in the analysis [29]. In a more recent RCT,
Emslie and colleagues (2006) could not replicate the superiority of paroxetine
over placebo.
In the treatment of anxiety disorders,
fluoxetine [30,31], fluvoxamine [32,33],
sertraline
[34],
paroxetine
[35],
have all shown greater efficacies than placebo in RCTs. Lastly, in the
treatment of pediatric OCD, fluoxetine [36,], fluvoxamine [37], sertraline [38,39], and
paroxetine
[40] have
demonstrated efficacy and superiority to placebo.
3.2. SNRIs
Extended-release venlafaxine [41],
duloxetine
[42,43],
and desvenlafaxine
[44]have
been proved effective in children and adolescents with depression, although
these results have not been consistent. In a separate study, Emslie and
colleagues determined that venlafaxine may be effective in depressed
adolescents, but not in younger children [45]. Authors did note that those taking
venlafaxine were more frequently troubled by suicidal and hostile thoughts, and
emphasized that the safety and efficacy of venlafaxine in pediatric patients
has not been adequately established. In a subsequent RCT by Emslie and
colleagues, results were inconclusive, as neither the investigational drug
(duloxetine) nor the active control (fluoxetine) significantly differed from
placebo [46]. Similarly, in a
placebo-controlled study of 40 children and adolescents with depression, the
combination of venlafaxine and psychotherapy was no more effective than
treatment with placebo and psychotherapy [47].
For the treatment of childhood and
adolescent anxiety disorders, extended-release venlafaxine [48,49] and
duloxetine[50] have
been shown more efficacious compared to placebo in RCTs. Data on SNRIs for the
treatment of child and adolescent ADHD is scarce, arecent review citing only 6
RCTs (5 venlafaxine, 1 duloxetine) [51]. Findings to date however, indicate
superiority of venlafaxine to duloxetine, which only demonstrated minimal
efficacy in the treatment of ADHD in pediatric populations [51], as well as superiority
to placebo
[52].
There were no available RCTs assessing desvenlafaxine for child and adolescent
psychiatric care other than for depression.
3.3. NDRIs
RCTs assessing NDRIs in children and
adolescents have focused mostly on ADHD, but have yielded mixed results. In a
small RCT assessing bupropion in adolescents with comorbid ADHD and depression,
participants exhibited significant improvement and the medication was well
tolerated [53]. In two separate
randomized double‐blind studies, bupropion demonstrated a
comparable safety and efficacy profile with methylphenidate (a Central Nervous
System (CNS) stimulant) in children and adolescents with ADHD [54,55]. More
recently, however, a meta-analysis determined that bupropion was less
efficacious than methylphenidate in reducing ADHD symptoms, and both were
inferior to lisdexamfetamine
[56].
However, more randomized, placebo-controlled studies of NDRIs in children and
adolescent depression are needed.
3.4. NaSSAs
In a US Federal Drug Administration (FDA) report on the efficacy
of mirtazapine in thetreatment of pediatric depression, results of two
randomized, placebo-control trials of the NaSSA were published [57]. No statistically
significant difference between mirtazapine and placebo was found in either
study; there is no evidence that mirtazapine is effective for the treatment
child and adolescent depression.
3.5. TCAs
In the previously mentioned CIHR funded
study of antidepressant use among children and adolescents in Quebec, TCAs were
the most frequently dispensed products among children (50.9%) [3]. Nevertheless, there have been few RCTs of
the efficacy of TCAs in children and adolescents. Studies thus far have demonstrated
TCAs are not significantly superior to placebo in the treatment of pediatric
depression or anxiety disorders. An RCT comparing imipramine, paroxetine, and
placebo for the treatment of adolescent depression, response to TCA
(imipramine) treatment was not significantly different from placebo across any
of the seven depression-related variables assessed, moreover study withdrawal
due to adverse events occurred in 31.5% of patients treated with imipramine,
nearly half of which experienced adverse cardiac events such as tachycardia or
arrhythmia [28]. Results from a
subsequent meta-analysis assessing the efficacy of TCAs and SSRIs in pediatric
populations found TCAs held no significant benefit over placebo in the
treatment of depression
[15].
In the treatment of children and
adolescents with anxiety disorders, clomipramine treatment showed no benefit
over placebo for the reduction of anxiety symptoms, although authors noted that
placebo response was unusually high [31]. In
a meta-analysis of pharmacological RCTs for the treatment of OCD in children
and adolescents, TCA treatment (clomipramine) was found to have a significantly
greater effect than SSRI treatments in the reduction of OCD symptoms [9]. However, authors posit that
clomipramine remains less “User-Friendly” in pediatric populations than the
SSRIs and due do frequent adverse events and concerns over potential
arrhythmogenic events, and suggest that the TCA should not be recommended as a
first line treatment for OCD in uncomplicated cases [9].
However, in a review of 6 RCTs for the
treatment of ADHD in pediatric populations, TCAs (desipramine, clomipramine,
and nortriptyline) outperformed placebo in the reduction of core ADHD symptom
severity and there were no serious adverse events reported in any of the
included trials[58].
However, Otasowie and colleagues stipulate that the effect of desipramine on
the cardiovascular system remains an important clinical concern and therefore
evidence supporting the clinical use of desipramine for the treatment of ADHD
in pediatric populations is low. Of interest, in the first randomized
controlled trial of amitriptyline versus gabapentin for pediatric neuropathic
pain, both medications proved similarly effective for decreasing pain scores
and improving sleep with no difference in adverse events reported [59].
3.6. MAOIs
There are few recent RCT of MAOIs in the treatment of child and
adolescent psychiatric disorders. In one of the earliest studies of
antidepressant drug treatment for child and adolescent depression, a
double-blind cross-over trial showed that MAOI phenelzine and chlordiazepoxide
(a benzodiazepine) were superior to phenobarbitone (a barbiturate) and a placebo [60]. However, in a
recent multisite, randomized, variable dose study to evaluate a Selegiline
Transdermal System (STS) for treatment of depression in pediatric patients,
neither selegiline nor placebo was found to be statistically superior [61].
There is
literature regarding small RCTs that suggest MAOIs may be safe and effective
for ADHD in children and adolescents. Two studies comparing MAOI selegiline to
methylphenidate for treatment of ADHD found no significant differences between
the two medications, and that selegiline was well tolerated [62,63]. When compared to placebo in a
double-blind crossover study of pediatric ADHD and comorbid Tourette’s
syndrome, post hoc analyses revealed a substantial effect by selegiline in the
group that received the active drug first in the crossover condition [64]. More recently,
authors of a placebo-controlled RCT found that while selegiline did not
specifically reduce symptoms of impulsivity, it was not associated with
negative side effects, and may be a preferred treatment for individuals who
present with the primarily inattentive subtype of ADHD [65]. Conversely, in a double-blind cross-over
study, an alternate MAOI, tranylcypromine, was efficaciously indistinguishable
from dextroamphetamine (a CNS stimulant) in the treatment of child and
adolescent ADHD
[66].
4. RCTs versus Naturalistic Studies
The “Gold Standard” of evidence-based
medical research is the double-blind, randomized, placebo-controlled study [67]. Participants either receive
the intervention, substance or treatment in question, or no treatment or
placebo, and neither researcher nor volunteer knows who belongs to which group.
The defining feature of RCTs is the random assignment of participants to these
conditions, and it is regarded as indispensable to ensure the observed effects
can be attributed exclusively to the applied therapy [68]. RCTs are therefore
intended to rule out bias and provide explicit evidence of a treatments efficacy [67]. The
main controversy of RCTs is the concern over the external validity of RCTs:
whether the results of RCTs are representative of clinical practice [68]. The strict control inherent
in RCTs gives rise to idealized conditions, promoting the study of isolated
disorders and restricted symptomology that rarely exists in real world clinical
practice. How germane the results of RCTs are to everyday practice cannot be
assessed without measurements of outcomes in the field [16].
In juxtaposition to RCTs, naturalistic
studies are carried out under the natural conditions of clinical practice.
Naturalistic studies are prospective “Non-Interventional” observational studies
of phenomena or retrospective analyses of existing data from previously
conducted studies, such as follow-up studies of previously treated participants
or chart review data [69].
Naturalistic studies of antidepressants have been employed to study a broader
range of clinically afflicted participants. Most RCTs have strict inclusion and
exclusion criteria that limit participation based on comorbidities, illness
severity, or medication history. Naturalistic studies, however, study
antidepressant agents in the “Real World” treatment of disorders without
excluding patients suffering from suicidal ideation or behaviour or any
co-morbidities, which so often occur in naturalistic samples. In this respect,
naturalistic studies can provide more generalizable results in comparison to
RCT efficacy trials
[8].
Therefore, RCTs and naturalistic studies serve different purposes and provide
answers to different domains of research questions. Helmchen (2011) [69] reasons
that naturalistic studies could be appreciated in conjunction with RCTs, as
they can provide additional valuable knowledge to compliment the results of
RCTs. Naturalistic studies provide the opportunity to observe clinician
prescribing behaviours, undesirable medication effects and adherence under real
world conditions, and the realistic course of treatment [69]. Long term naturalistic
prospective studies in pediatric patients represent an important source of
information for routine care regarding the effectiveness, safety, and
tolerability of treatment over extended periods under routine clinical
conditions
[16].
5. Naturalistic Studies of Antidepressant
Drug Treatment in Children and Adolescents
5.1. SSRIs
In an open, naturalistic study of 211
children and adolescents in Sweden, SSRIs were found to be the most prescribed
antidepressant drug treatment, sertraline being the most common (67% of SSRIs).
The indication for which antidepressant treatment is most commonly prescribed
in the pediatric population was depression (69%), OCD second (14%), anxiety
disorders (11%), dysthymic disorder (2%) and eating disorder (1%; [11]. A similar
perspiration pattern was found in a study of antidepressant tolerability in anxious
and depressed youth at high risk for bipolar disorder. SSRIs were also the most
had been prescribed for 66% of these youths, 38% had taken bupropion, and 5%
duloxetine
[70].
57% of these high risk youth had an adverse reaction to antidepressant treatment
that led to discontinuation, the most common cause being increased
irritability, followed by aggression. Younger patients were more likely to
experience antidepressant-induced adverse events and the authors observed
trends toward higher irritability and motor hyperactivity in patients who
subsequently developed adverse events with antidepressant treatment [70].
The most widely ‘real world’ studied
SSRI in pediatric psychiatric populations is fluoxetine. In a naturalistic
1-year follow-up study of 87 children and adolescents who had participated in
an 8-week RCT of fluoxetine for depression conducted by Emslie and colleagues
(1998) [19], symptom response to
fluoxetine was superior to placebo. Of those treated with fluoxetine, 81%
recovered within 12 months with an average time to recovery of over 2 months
(69.4 days) and for those with recurrence, occurring at average 6 months (176.6
days) following recovery
[19].
Similarly, in a naturalistic study on the efficacy and safety of fluoxetine in
young patients (11-23 years), patients showed improvement in their symptomology
over time, including suicidality, and adverse events of the naturalistic study
were lower when compared to controlled trials [71]. In another naturalistic 1-year follow-up
study, results showed that when combined with Cognitive Behavioural Therapy
(CBT), fluoxetine treatment reaches maximum benefit earlier (18 weeks) than
either treatment alone (30 weeks for fluoxetine, 36 weeks for CBT), and that 9
months of treatment was superior to 12 weeks irrespective of treatment arm [72]. These
results confirm those of a previous naturalistic study on combined fluoxetine
and psychosocial therapy [73]. Most recently, fluoxetine was determined
effective for the acute treatment of social anxiety disorder in children and
adolescents, and it well tolerated except for mild and transient headaches and
gastrointestinal side effects. Very few (5%) of the patients discontinued the
fluoxetine because of side effects (increase in irritability) [74].
In another study on relation between
dosage, serum concentration, and clinical outcome in children and adolescents
treated with sertraline, no significant association between the serum
concentration and the reported therapeutic response or the occurrence of side
effects, however there was a trend that side effects occurred more frequently
and with greater severity in adolescents than in children [75]. In a naturalistic study
examining the effectiveness and safety of paroxetine for children and
adolescents with panic disorder, the SSRI was well tolerated and effective for
83% of patients and there were no treatment interruptions due to side effects [76],
replicating the results of Wagner and colleagues’ RCT (77.6% response rate;
2004)
[25]. However, in a naturalistic study assessing the
long-term treatment of panic disorder with clonazepam (a benzodiazepine) or
paroxetine, there was a significant advantage with clonazepam over paroxetine
with respect to the frequency and nature of adverse events [77]. In an analysis of 23
cases of pediatric obsessive compulsive disorder treated with citalopram, over
75% showed a marked or moderate improvement in OCD symptoms [78],
a response rate higher than those reported in RCTs (56.1%) [79],
and any adverse effects were minor and transient.
5.2. SNRIs
There were no available naturalistic studies assessing SNRIs in
child and adolescent psychiatry.
5.3. NDRIs
There were no available naturalistic studies
assessing NDRIs in child and adolescent psychiatry.
5.4. NaSSAs
There were no available naturalistic studies assessing NaSSAs in
child and adolescent depression. One naturalistic study of mirtazapine in
pediatric populations was found for the treatment of associated symptoms of
autism and other Pervasive Developmental Disorders (PDDs). Overall, mirtazapine
was well tolerated but showed only modest effectiveness (34.6%) for treating
the associated symptoms of autistic disorder and other PDDs [80]. The minimal adverse
events reported consisted of increased appetite, irritability, and transient
sedation
5.5. TCAs
The only naturalistic study on TCAs in child and adolescent
psychiatry focused on the predictability and stability of desipramine
concentrations in pediatric samples. Authors found wide between-patient
variability in serum desipramine levels at the same dose, however future
within-subject blood levels were highly predictable by knowing current levels,
current dose, and the future dose [81]. No naturalistic studies were available
for the efficacy and safety of other TCA agents in child and adolescent
psychiatry.
5.6. MAOIs
There were no available naturalistic studies assessing MAOIs in
child and adolescent psychiatry.
6. Discussion
To date, greater focus has been paid to
the methodological and ethical considerations of RCTs than on naturalistic
studies [67,69,82]. Helmchem (2011) [69] purposes
this is because RCTs are interventional in nature and pose greater potential
somatic and psychosomatic risks, whereas naturalistic studies are observational
with an analytic focus. Generally, naturalistic trials pose no individual
benefit to the participant, and therefore are assumed to have fewer or no risks [69].
It is important to
appreciate, however, that in all classes of scientific study there are inherent
risks, no matter how salient. The major methodological and ethical
considerations of naturalistic studies are the method and content of informed
consent, psychological burdens of questionnaires and/or interviews,
psychological consequences of the observational procedures, and the
confidentiality of recorded data. Two additional areas of great concern in
naturalistic studies are the potential of stigmatization by case selection and
dealing with incidental findings.
Most patients in naturalistic settings
are not pharmacologically naïve and do not remain on the same antidepressant
dosage for the duration of treatment, which may result in cross-tolerance or
change side-effect reporting [83].
Therefore, while RCTs may be criticized over their external validity, a main
argument against naturalistic studies regards threats to internal validity.
However, according to Leichsenring (2004) [84],
RCTs and naturalistic studies do not differ in their internal or external
validity. The author purposes that in RCTs, laboratory hypotheses and
laboratory modifications of therapy are tested, whereas in naturalistic
studies, field hypotheses and field therapies are tested (2004). As such, RCTs
should not be considered to provide a higher level of evidence than
naturalistic studies, but rather that each domain of research provides the
necessary evidence for their domain of application. Nevertheless, the use of
additional design elements can help minimize possible threats to internal
validity of naturalistic studies. According to both Leichsenring (2004) and
Helmchen (2011)
[69,84],
a high-level prospective naturalistic study should use systematic and
standardized observations at multiple time points and a schedule for data
analysis determined prior to commencement. In addition, non-random comparison
groups, matching or stratifying of groups, use of reliable and valid diagnostic
procedures and outcome measures, pre- and post-assessments, and follow-up
studies all contribute to a scientifically sound naturalistic study [84].
7. Conclusion
The purpose of this report was to
conduct review of antidepressant medications, their applications, and the
controlled and naturalistic assessment to date in pediatric populations, in order
to effectively inform a proposal for a realistic and comprehensive prospective
naturalistic study of antidepressant medication in child and adolescent
psychiatry. Antidepressant agents have successfully been applied in the
treatment of many pediatric psychiatric disorders, such as depression, anxiety
disorders, OCD, and ADHD, as demonstrated by RCTs. Of which the most evidence
has been gathered on the antidepressant class SSRIs. However, there is little
knowledge of the effectiveness of antidepressant treatments in pediatric
psychiatry services in naturalistic “Real World” settings [11,85]. Given the
wide-ranging application of antidepressants in everyday care, the efficacy
rates in clinical trials may not be replicated in clinical practice. Therefore,
it is imperative to conduct effectiveness studies of antidepressants in
treatment-as-usual for children and adolescents, to complement RCTs. Further
naturalistic studies are necessary to ensure that children are not exposed to
unnecessary risk, and to determine the most appropriate agents and doses in
children of different ages with different diagnoses [11]. Although there are inherent limitations of
naturalistic studies, a number of strategies have been highlighted to bolster
internal validity, such as non-random comparison groups and stratifying of
groups. Given the paucity of naturalistic studies in diagnostically
heterogeneous pediatric populations, the results of studies of this kind will
help us better understand the efficacy, tolerability, and safety of antidepressant
agents in children and adolescents.
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