year 2000 for atypical depression, but were not as efficacious as MAOIs, and have fallen out of favor with prescribers due to the less tolerable side effects of TCAs and more adequate therapies being available. One pilot study suggested that psychotherapy such as cognitive behavioral therapy (CBT) may have equal efficacy to MAOIs for a subset of patients with atypical depression, although the sample size was small and statistical significance was not reached. These are talk therapy sessions with psychiatrists or clinical psychologists to help the individual identify troubling thoughts or experiences that may affect their mental state, and develop corresponding coping mechanisms for each identified issue. Epidemiology True prevalence of atypical depression is difficult to determine. Several studies conducted in patients diagnosed with a depressive disorder show that about 40% exhibit atypical symptoms, with four times more instances found in female patients. Research also supports that atypical depression tends to have an earlier onset, with teenagers and young adults more likely to exhibit atypical depression than older patients. Patients with atypical depression have shown to have higher rates of neglect and abuse in their childhood as well as alcohol and drug disorders in their family. Overall, rejection sensitivity is the most common symptom, and due to some studies forgoing this criterion, there is concern for underestimation of prevalence. Research Atypical depression was first thought of as a disorder separate from typical depression in 1959, when doctors E.D. West and P. J. Dally were studying the effects of iproniazid, an MAOI, on patients with depression. They found consistencies among the patients who responded well to the drug in comparison to those who didn't. These patients, who were displaying symptoms of "anxiety hysteria with secondary depression", responded notably well to the iproniazid. In general, atypical depression tends to cause greater functional impairment than other forms of depression. Atypical depression is a chronic syndrome that tends to begin earlier in life than other forms of depression—usually beginning in the teenage years. Similarly, patients with atypical depression are more likely to have anxiety disorders, (such as generalized anxiety disorder, obsessive-compulsive disorder), bipolar disorder, or personality disorders (such as borderline personality disorder, avoidant personality disorder). Recent research suggests that young people are more likely to experience hypersomnia while older people are more likely to experience polyphagia. Medication response differs between chronic atypical depression and acute melancholic depression. Some studies suggest that the older class