MENTAL DISEASES. – Morbid states also called frenopathies, psychopathies, psychoses, which manifest themselves in acute or chronic form with disturbances of psychic activity, whether intellectual (noopsychic), affective, instinctive, or emotional ( thymosic), when the brain is structurally altered or functionally impaired by exogenous morbid causes (trauma, tumors, toxic infections, endocrine disorders, emotions, etc.) or endogenous ones (degenerative, atavistic, hereditary); the latter often determining a congenital debility and a reduced resistance in the nervous centers, predisposing the individual to the action of exogenous causes, so that not infrequently the two types interpenetrate and combine in the genesis of psychopathies.
As regards the causal value of emotions, a careful examination of the patient and his antecedents always reveals the pre-existence of a psychopathic constitution or of the mental illness itself already in progress for some time, so that the psychic trauma assumes the value of a revealing element or that of a co-cause in the determination of a reactive psychosis sprouting on a constitutionally predisposed terrain. The most intimate causes and the pathological anatomy of mental diseases, except for a few, are uncertain and imprecise, and for some even unknown; this uncertainty affects their classification, which varies greatly according to the concepts upheld by different schools. In general terms, a first generic distinction is admitted between organic forms and functional forms, based on the concept of the existence or absence of a demonstrable anatomical alteration supporting their symptomatology.
By way of a generally orientative title, the classification based on clinical and etiological criteria adopted by the Statistical Office of Rome for the reporting of mental diseases is given here; it is based on that of Kraepelin, also founded on clinical and etiological criteria. Many others exist, since each author, studying mental diseases from his own point of view, arrives at different nomenclatures and frameworks, which, however, often differ more in external form than in substance. *Frenasthenia* (v.) or *oligophrenia* (with or without evident brain lesions); *psychopathic personalities* (moral insanity, paranoia and querulous delusion, prison psychosis, sexual psychopathies, psycho-neuroses such as hysteria, neurasthenia, phobia, etc.); *epileptic psychoses*; *affective psychoses* (depressive, manic, manic-depressive); *dementia praecox* (schizophrenia, in its various forms); *endogenous toxic psychoses* (linked to internal factors: endocrine, constitutional, metabolic); *exogenous toxic psychoses* (from voluntary or medicinal intoxications); *infectious psychoses* (in relation to syphilis, tuberculosis, typhoid, encephalitic viruses, etc.); *senile psychoses* (involutional, arteriosclerotic, etc.); *psychoses from organic encephalopathies* (trauma, tumors, etc.).
The uncertainty of causes and the consequent imprecision in classification inevitably reflect on the therapy of psychoses, which, very often, particularly for the more obscure ones, is limited to a purely symptomatic level. On the other hand, it cannot be denied that, particularly in recent years, significant progress has been made in treatment and appreciable results have been achieved through recent *shock* methods (insulin, electric, cardiovascular, acetylcholinic, etc.), mainly in schizophrenia and dysthymias; with the malariotherapy of progressive paralysis. With these methods of treatment, it is often possible, if not to achieve true cures, to obtain improvements such that many psychopaths, previously doomed to chronicity, can be restored to family life and society, even to productive work. The prognosis remains unfavorable for cases with a severe course, resistant to any intervention, and in degenerative and involutional psychopathic conditions. In forms considered to be functional, particularly psycho-neuroses (hysteria, psychasthenia, anxious forms, neurasthenia or alarm syndrome, etc.) and where emotional psychological factors prevail, *psychotherapy* (v.) is widely used, possibly in conjunction with drug treatments, as well as *narcoanalysis* (v.) and prolonged sleep, recently introduced into therapy. Most recent of all is the surgical treatment of psychopathies, which, with *lobotomy*, *lobectomy*, *topectomy*, aims to isolate or even destroy more or less extensive regions of the cerebral cortex; it derives, developed and expanded in its applications, from *prefrontal leucotomy* first performed by Moniz in 1936 and still in use. These operations are now frequently performed, with varying results, in the treatment of obsessive psychosis, cyclothymia in general, schizophrenia, epilepsy, and post-encephalitic syndromes. No less important than treatment is the prophylaxis of mental diseases, especially with regard to alcoholic psychoses and neurosyphilis, carried out through appropriate propaganda, outpatient visits, repeated health and biological controls, with the aim of preventing and detecting psychopathies, particularly toxic and infectious ones, in their initial phase, when treatment is most effective and progression can be more easily halted before it becomes irreversible.
As regards the state of intelligence, the modalities of character, and moral responsibility in mental diseases, see the respective entries, in particular the various "psychoses."