Pharmacotherapy of early-onset depression. Update and new directions

Although an increased recognition of depressive disorders in youth represents a positive conceptual change over the past decades, there still is a very limited amount of research on useful treatment interventions. The paucity of data is particularly keen for the use of psychotropic drugs. For example, by applying the criteria suggested by the International Psychopharmacology Algorithm Project, there barely are enough first-grade ("Level A," meaning at least two RCTs) data supporting the short-term efficacy of antidepressants (the SSRIs) in the treatment of juvenile depression. And yet, limited data have not translated into limited use in routine clinical practice. In fact, the use of antidepressant medications has increased exponentially over the last decade, a change that is especially conspicuous for individuals less than 18 years of age. The perceived safety of the SSRIs and other novel antidepressants is partly at the root of their increased popularity. Data regarding their safety are likewise quite limited, however, and essentially are nonexistent for longer-term use. Based on the reviewed data, a medication algorithm for the treatment of early-onset depression can be suggested (Fig. 1). The algorithm underscores the need for adequate evaluation and diagnostic assessment, with particular attention to comorbid conditions (such as a bipolar diathesis) that may dictate alternative treatment strategies. In general, psychotherapy is the initial approach to juvenile MDD, with medication use reserved for more severe cases or those not responding to psychotherapy alone. Given that only two types of psychotherapy and two SSRIs have adequate controlled short-term efficacy data, all but the initial steps must be undertaken guided by clinical judgment and an individualized risk-benefit analysis. An algorithm such as this one, based on the very limited efficacy and safety data available, may be viewed as setting priorities for a comprehensive research agenda, more than dictating rigid treatment guidelines. In closing, it can be suggested that future research on the pharmacotherapy of early-onset depressive disorder pay particular attention to the following three aspects: 1. Too many drugs, too few data: Rapid advances in drug development have led to a plethora of available antidepressant agents. It is clear that there are many more agents available than can be adequately studied at present. Because many such agents are mechanistically similar, if not identical, it may be wise to focus research efforts on truly novel agents, particularly those (such as the CRH receptor antagonists, or those affecting neurosteroidogenesis) whose action is based on preclinical and clinical pathophysiologic disease paradigms. 2. Longitudinal follow-up and maintenance studies: Essentially all reviewed treatment studies have been short-term trials. There is a marked paucity of longer-term follow-up data, or of naturalistic and "real-world" effectiveness studies. For example, one of the few studies addressing maintenance pharmacotherapy for early-onset depression has demonstrated surprisingly high recurrence rates, even for those subjects actively on maintenance medication. 3. Long-term safety: Clinicians and parents alike often face difficult decisions regarding the long-term exposure of antidepressant drugs on the developing brain. Although no definitive long-term safety data are likely to become available anytime soon, real risks, such as suicide, and potential sequelae of long-term exposure to the underlying illness itself need all to be part of any decision-making process. Preclinical studies have shown that brain-derived neurotrophic factor (BDNF) levels can be upregulated by antidepressants, and low BDNF factors have been associated with atrophic brain changes in recurrent forms of adult MDD. Although these observations require specific application to juvenile forms of the disorder, they raise the exciting prospect that the natural course of the illne