Depression clinical features

Identify symptoms and clinical features of major depressive disorder. 

The American Psychiatric Association diagnostic criteria are listed in Table 19.1. Table 19.2 describes the clinical features and Table 19.3 lists medical illnesses and drugs that can cause depressive symptoms. 

The nature of the neurochemical impairment underlying depressive illness remains elusive. There is a great deal of evidence supporting roles for the 5-HT system and the HPA axis. However the evidence is less clear that an abnormality in one system alone can explain the full extent of the clinical features of depressive illness. Subtle abnormalities in the interactions between the HPA axis and the serotonergic system may lead to profound alterations in the functioning of both systems, and it may be this that results in the range of symptoms found in mood disorders. 

Clinicians must be aware of this rare but potentially serious problem. It may be difficult to distinguish serotonin syndrome from the clinical features of depression, adverse effects, and withdrawal effects. 

Clinical features of weakness, ataxia, drowsiness, and short-term memory loss can be seen within 30-60 minutes. Coma and respiratory depression are rare but can occur with the ultrashort-acting agents like triazolam and midazolam. Diagnosis is made from the patient history. 

Poisoning with opiates such as morphine, pethidine, and heroin is increasingly common as opiate abuse becomes more widespread. The drugs are often injected or inhaled. The cardinal clinical features are coma, pin-point pupils and respiratory depression, which strongly suggest opiate poisoning. 

The first report on cortisol levels in PTSD was that of Mason et al. who found that the mean 24-h urinary excretion of cortisol was significantly lower in combat Vietnam veterans with PTSD compared to psychiatric patients in four other diagnostic groups (Mason et al. 1986). The authors noted surprise at the fact that cortisol levels were low, since certain clinical features such as depression and anxiety [in PTSD] might have been expected to be associated with increased activity of the pituitary-adrenal cortical system. Since this initial observation, the majority of the evidence supports the conclusion that cortisol alterations in PTSD are different from those observed in acute and chronic stress, and major depression, but more importantly, that the HPA axis appears to be regulated differently. 

A 76-year-old woman, who had a history of hypertension, valvular heart disease (mitral regurgitation) with chronic atrial fibrillation, chronic obstructive airways disease, diverticular disease of the sigmoid colon, and generalized anxiety disorder, developed severe hypotension with a tachycardia after taking alprazolam for 7 days. She also had severe weakness, depressed mood, and impaired gait and balance, without clinical features of neuromuscular disease. 

LITHIUM CENTRALLY ACTING ANTI HYPERTENSIVES 1. Methyldopa may reduce the effect of antidepressants 2. Case reports of lithium toxicity when co-ingested with methyldopa. It was noted that lithium levels were in the therapeutic range 1. Methyldopa can cause depression 2. Uncertain at present 1. Methyldopa should be avoided in patients with depression 2. Avoid co-administration if possible if not, watch closely for clinical features of toxicity and do not rely on lithium levels... 

FLUOXETINE, FLUVOXAMINE, PAROXETINE BZDs - ALPRAZOLAM, DIAZEPAM, MIDAZOLAM t in plasma concentrations of these BZDs. Likely t sedation and interference with psychomotor activity Alprazolam, diazepam and midazolam are subject to metabolism by CYP3A4. Fluvoxamine, fluoxetine and possibly paroxetine are inhibitors of CYP3A4 sertraline is a weak inhibitor. SSRIs are relatively weak compared with ketoconazole, which is possibly 100 times more potent as an inhibitor Warn patients about risks associated with activities that require alertness. Consider use of alternatives such as oxazepam, lorazepam and temazepam, which are metabolized by glucuronidation >- For signs and symptoms of CNS depression, see Clinical Features of Some Adverse Drug Interactions, Central nervous system depression... 

The clinical features of overdose with etiichlorvynol resemble those due to poisoning with other hypnotics, but coma is often prolonged and accompanied by severe respiratory depression. Ethchlorvynol has a pungent odour which is often detected in the stomach contents. A qualitative test for ethchlorvynol in stomach contents is given on p. 6. A gas chromatographic mediod for the quantification of ethchlorvynol in plasma is given on p. 17. 

Older classifications of psychiatric disorder divided diseases into psychoses and neuroses. The term psychosis is still widely used to describe a severe mental illness with the presence of hallucinations, delusions or extreme abnormalities of behaviour including marked overactivity, retardation and catatonia, usually accompanied by a lack of insight. Psychotic disorders therefore include schizophrenia, severe forms of depression and mania. Psychosis may also be due to illicit substances or organic conditions. Clinical features of schizophrenia may be subdivided into positive symptoms, which include hallucinations, delusions and thought disorder and negative symptoms such as apathy, flattening of affect and poverty of speech. 

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