Denosologization of biological psychiatry or the specificity of 5-HT disturbances in psychiatric disorders

Strain-specific effects of antidepressants on escape deficits induced by inescapable shock

The effects of several antidepressants (desmethylimipramine, amitriptyline and bupropion) on escape deficits induced by inescapable shock were assessed in four strains of mice. The extent of the escape interference engendered by inescapable shock varied across strains of mice. These deficits of escape performance were differentially affected by the drug treatments across strains. Repeated administration of desmethylimipramine eliminated the escape interference in A/J, but did not affect the performance in Balb/cByJ, C57BL/6J or CD-1 mice. Bupropion, in contrast, had a modest effect only in CD-1 mice. Unlike these compounds, the 5-HT reuptake blocker, amitriptyline, was found to influence escape performance irrespective of whether the drug was acutely or chronically applied. It is suggested that (a) the relative contributions of various mechanisms subserving the escape interference may vary across strains of mice, hence accounting for the strain-specific effects of the drug treatments, and (b) various antidepressants influence performance by affecting different components of the behavioral output, some of which may be apparent after acute treatment while others are expressed only after repeated treatment with the compound.

Growth hormone response to desmethylimipramine in depressed and suicidal adolescents

Desipramine 75 mg i.m. was given in the morning to 20 adolescents with major depressive disorder and 23 normal controls. Depressed adolescents secreted significantly less growth hormone (GH) over the next 2 h than did normal adolescents, although a substantial proportion of the differences were accounted for by the depressed adolescents who had a specific suicidal plan or attempt during the episode. Severity of depression or the presence of other depressive symptoms did not predict GH secretion within the depressed group. Age, sex and maturational factors in the control of GH are discussed. It is concluded that these differences in GH secretion probably reflect differences in CNS beta-adrenergic and/or serotonergic function. Suicidality and depression may have different psychobiological correlates in adolescents.

L-tryptophan: a rational anti-depressant and a natural hypnotic?

L-tryptophan is an essential amino acid which is the metabolic precursor of serotonin. Because of the evidence that serotonin deficiency may be an aetiological factor in some sorts of affective disorder and that serotonin is important in the biochemistry of sleep, L-tryptophan has been suggested as a "rational" anti-depressant and as a "natural" hypnotic. This paper reviews the biochemistry and pharmacology of L-tryptophan as well as the literature of the clinical trials that have been conducted with it and suggests that, by itself, L-tryptophan may be useful in mild cases of depression accompanied by endogenous features and cases of bipolar disorder resistant to standard treatments. It also potentiates the monoamine oxidase inhibitors and possibly the serotonergic tricyclic drugs. L-tryptophan may improve the depressed mood of Parkinsonian patients and has a clinically useful hypnotic action. There is evidence it may be useful in organic mental disorders induced by levodopa. Dosage schedules, contraindications and complications are discussed.

Involvement of serotonin system in bulimia

Platelet 3H-imipramine binding was investigated in 8 patients affected by bulimia according to DSM III criteria, and in 7 healthy volunteers. The Bmax +/- SD (fmol/mg protein) was 356 +/- 53 in patients, and 1144 +/- 134 in controls. The Kd +/- SD (nM) was 1.35 +/- 0.44 in patients, and 1.90 +/- 0.72 in controls. There was a significant difference (p less than 0.0001) in Bmax values in the two groups, whereas no significant difference was observed in Kd values. This study suggests the possible involvement of the indoleamine system in bulimia.