There exist a group of patients commonly seen in primary care as well as psychiatric settings that exhibit admixtures of depressive and anxiety symptoms that fluctuate over time on a subacute or chronic basis. They are variously referred to as anxious depressives, mixed anxiety depressives, and atypical depressives. A longitudinal perspective is necessary to determine the temporal relationship between the depressive and anxiety symptoms. When anxiety symptoms antedate depressive manifestations —and this is often the case in young individuals—then the likelihood is that this is a neurotic illness complicated by depression. Patients who have suffered from many years of generalized anxiety or full-blown panic attacks gradually get demoralized and disgusted with themselves; insomnia in the first half of the night leads to a tendency to feel fatigued and hypersomnolent in the morning, hence the origin of several of the symptoms that are considered to be atypical depressive manifestations. Even in the original British reports (13,17), these atypical depressive patients with neurasthenic symptoms were ba­sically considered anxiety neurotics. In these patients studied in our sleep lab­oratory, polysomnographic findings have failed to reveal REM sleep findings characteristic of primary depressive illness, and instead have shown features observed in anxiety disorders (i.e., multiple awakenings in the first half of the night). Hence our contention that a subgroup of atypical depressives is more appropriately described as atypical anxiety disorder, and would therefore benefit from monoamine oxidase inhibitors or alprazolam. Other depressives with atyp­ical features conform to the subaffective dysthymic pattern and are more likely to respond to noradrenergic tricyclics and lithium carbonate (1); these patients represent genuine forms of primary mood disorder and are unrelated to anxiety disorders. In other words, there seem to be at least two types of atypical depression (7), of which one with anxious depressive features is more accurately classified as an anxiety disorder. When anxiety symptoms occur in the setting of depressive manifestations — and this is often the case in older individuals—one must give preference to the diagnosis of a primary depressive illness. As emphasized in DSM-III (6), an anxiety disorder rarely, if ever, begins after the age of 40. Unfortunately, this fact is sometimes forgotten and manifestations indicative of autonomic nervous system hyperactivity are automatically ascribed to a neurotic illness. Indeed, once physical illness is excluded, the diagnosis of an anxiety state, rather than primary depressive illness, is initially entertained by many primary care physi­cians. What complicates differential diagnosis is the fact that some of these pa­tients completely deny the subjective psychological symptoms of mood disorder, e.g., depression, anhedonia, lowering of self-esteem, guilt, suicidal ideation, etc. Among the masked depressives studied in our sleep laboratory, about a dozen were middle aged or elderly patients (in their late 40s or older) who presented with such symptoms as sudden awakening with intense autonomic arousal and the fear of dying in their sleep. None of these patients had experienced panic attacks in their younger years or had premorbidly exhibited neurotic patterns. Elderly individuals with no psychiatric illness showed modest shortening of their REM latency. But even after taking this fact into consideration, the patients we studied with fear of dying in their sleep and other autonomic manifestations of anxiety had sleep EEG findings characteristic of primary depression. It would appear that the mere presence of anxiety attacks is not diagnostic of anxiety neurosis in that such attacks appearing for the first time after age 40 may represent affective equivalents. Melancholic patients presenting in this way are typically agitated and experience intense apprehension; they may even harbor delusions regarding calamities to themselves and their loved ones, which confirms the diagnosis. These agitated melancholias should be treated like other primary depressives. The use of benzodiazepines, if needed, should be purely on a symp­tomatic basis and limited to short periods of time to supplement standard an­tidepressant therapy.

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