Schizophrenia cognitive impairment

Emrich HM, Leweke EM, Schneider U. Towards a cannabinoid hypothesis of schizophrenia cognitive impairments due to dysregulation of the endogenous cannabinoid system. Pharmacol. Biochem. Behav. 56, 803-807 (1997). 

Johnstone EC, Crow TJ, Frith CD, Stevens J and Kreel L (1976). Cerebral ventricular size and cognitive impairment in chronic schizophrenia. Lancet, 1, 924-926. 

Schizophrenia is characterized by three partially independent symptom clusters. These symptom clusters are designated positive symptoms, negative symptoms and cognitive impairments [1], The positive symptoms are the most dramatic and are manifestations of psychosis. 

Controlled clinical investigations with careful titration of doses in normal subjects demonstrate that ketamine produces negative symptoms, such as withdrawal and the subtle cognitive impairments associated with schizophrenia [25]. As is the case for schizophrenia, these symptoms occur without clouding of consciousness or frank dementia. Positive symptoms with auditory hallucinations and fully... 

Much of the current knowledge about cognitive impairment in schizophrenia... 

Egan. M.F., Goldberg, T.E., Gscheidle, T., et a . Relative risk for cognitive impairments in siblings of patients with schizophrenia. Biol. Psychiatry 50, 98-107, 2001. 

Sedation, ataxia, and cognitive impairment may occur with higher BZD dosages. Other adverse effects reported in the treatment of schizophrenia include the following ... 

Sedation, ataxia, and cognitive impairment occur more frequently with high BZD dosages. Other adverse effects reported when BZDs were used to treat schizophrenia include behavioral disinhibition, exacerbation of psychosis, and increase in anxiety and depression ( 163, 188, 189,190, 191,192, 193,194 and 195, 351). Concomitant use of a BZD and the atypical antipsychotic clozapine may increase the risk of sedation, dizziness and collapse with loss of consciousness ( 196). Respiratory compromise has also been reported with this combination (395, 396). 

Much remains to be discovered about the underlying pathophysiology of schizophrenia and there is still a great need for medicinal chemists to develop more selective drugs that are devoid of clinically limiting side-effects and also address the cognitive impairment symptoms. 

Wade et al. (1987) pointed out that Huntington s and Parkinson s diseases provide a related model for TD, including the development of cognitive impairments (see Koshino et al., 1986 Breggin, 1993, for similar discussions). They studied 54 patients who were diagnosed with mania or schizophrenia with TD and concluded that TD is one expression of a... 

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