[Depressive symptomatology and sleep apnea syndrome]

The sleep apnea syndrome (SAS), which is defined by more than 5 apneas or hypopneas per hour of sleep (9), is quite a frequent affection which concerns 1.4 to 10% of general population (1.7). The major daytime complaints of the SAS are daytime sleepiness, memory and attention disorders, headaches and asthenia especially in the morning, and sexual impotence (9). The nocturnal manifestations are dominated by sonorous and generally long standing snoring, increased by dorsal decubitus and intake of alcohol, with repeated interruptions by respiratory arrests. These manifestations are always noted but rarely spontaneously reported. The sleep, non refreshing, is agitated and perturbed by numerous awakenings. The findings of the clinical examination are poor: obesity is found in 2/3 of the cases and arterial hypertension in 1/2 of the cases (20). Polygraphic recording during sleep only permits an absolute diagnosis. This frequent affection is a real problem of public health because of its numerous complications (3, 10, 12, 13, 18, 21). Symptoms of depression are often found when a patient with a SAS is examined and conversely, symptoms which evoke a SAS can be found in the clinical examination of depressed patients. We decided so to study the thymic and anxious status of 24 patients investigated for a SAS and submitted to a polygraphic recording during sleep. Four clinical parameters were studied: DSM III-R diagnosis criteria, Montgomery and Asberg Depression Rating Scale (MADRS), Hamilton Anxiety Rating Scale (HARS) and thymasthenia rating scale of Lecrubier, Payan and Puech. We also reported Total Sleep Time (TST = 6.5 +/- 1.5), Apnea Hypopnea Index (AHI = 26.7 +/- 21.6), number (2.1 +/- 2.8/h) and duration (174.2 +/- 150.8 s/h) of hypoxic events. Results showed that among 24 patients, 8 were depressed according to DSM III-R diagnosis criteria and had MADRS > 25, 22 were anxious, 11 had a major anxiety (HARS > 15) and 15 presented thymasthenia (SET > 15). Significative correlations existed between anxiety and depression (r = 0.82; p < 0.0001), depression and thymasthenia (r = 0.77; p < 0.0001) and thymasthenia and anxiety (r = 0.75; p < 0.0001). Among the 8 depressed patients a correlation existed between AHI and depression (r = 0.72; p = 0.04), but no correlation was found between depression and hypoxic events. These results were comparable to those of Guilleminault (10), Reynolds (21), Kales (12), Bliwise (3), Klonoff (13) and Millman (18) who studied relations between SAS and depression. The evaluation of thymasthenia gave a more precise typology of the depressive state associated to SAS: the type of the mood disorder is more "blunted" and "anhedonic" than "sorrowful", particularly characterised by asthenia, lack of energy, reduction of interests (leisures, libido, work), loss of initiative, difficulties to organise tasks, fall of performances and reduction of pleasure usually felt in pleasant events (15). The physic symptomatology dominated the psychic one. The sleep disorganization, more than metabolic consequences of apneas, could be involved in this associated depressive state. Other neuropsychiatric troubles can be associated to the SAS. In fact, cognitive troubles (2, 8, 14, 16, 19, 22, 24) and personality disorders (12, 18) have been described. Our data confirm previous observations suggesting a frequent association between SAS, depression, fatigue and anxiety. Clinicians should consequently be aware that a depression with severe complaints of fatigue should deserve an investigation oriented towards SAS. Conversely, when a SAS is diagnosed, it is necessary to look for a possible depression in order to set up the most appropriate treatment. The frequency of SAS, like depression's one, increases with age. Prescription and consummation of sedative psychotropic drugs increase too with age. Since respiratory depressant effects of these drugs have been clearly demonstrated, it is important to evoke SAS when depressive and/or anxious states are diagnosed and not to aggravate it. An efficacious treatment of SAS can also cure the associated depressive state, but this one can persist. It is necessary, in this case, to select a non sedative antidepressant.