Since 1863 psychiatry is dominated by the nosological conceptual paradigm that was further stimulated by the introduction of the DSM-III. This has resulted in an ignorance of the European psychiatric diagnostic tradition and a loss of the necessary critical observations and descriptions of psychopathology. This unfortunate process may be observed in the diagnosis of psychiatric disorders in mentally retarded patients where entities such as atypical psychoses, unstable mood disorder and motivational deficit syndrome are not recognized in general. The enormous increase of neuroscienti-fic knowledge, particularly the impact of genetic and intracellular mechanisms in the pathophysiology of psychiatric disorders, warrants the use of a more dimensional and functional psychiatric paradigm. It concerns the effect of gene transcription on the expression of neurotransmitters and receptors that may account for an increased vulnerability or a relapsing course. A so called anticipatory treatment approach is therefore advocated.

This review addresses the hypothesis that polyunsaturated fatty acids (PUFA), particularly those of the n-3 family, play essential roles in the maintenance of energy balance and glucose metabolism. The data discussed indicate that dietary PUFA function as fuel partitioners in that they direct glucose toward glycogen storage, and direct fatty acids away from triglyceride synthesis and assimilation and toward fatty acid oxidation. In addition, the n-3 family of PUFA appear to have the unique ability to enhance thermogenesis and thereby reduce the efficiency of body fat deposition. PUFA exert their effects on lipid metabolism and thermogenesis by up-regulating the transcription of the mitochondrial uncoupling protein-3, and inducing genes encoding proteins involved in fatty acid oxidation (e.g. carnitine palmitoyltransferase and acyl-CoA oxidase) while simultaneously down-regulating the transcription of genes encoding proteins involved in lipid synthesis (e.g. fatty acid synthase). The potential transcriptional mechanism and the transcription factors affected by PUFA are discussed. Moreover, the data are interpreted in the context of the role that PUFA may play as dietary factors in the development of obesity and insulin resistance. Collectively the results of these studies suggest that the metabolic functions governed by PUFA should be considered as part of the criteria utilized in defining the dietary needs for n-6 and n-3 PUFA, and in establishing the optimum dietary ratio for n-6 : n-3 fatty acids.