[Drug-related increase of intelligence level. Considerations and a double-blind-study with flunarizin (sibelium) (author's transl)].

Fluid and crystallized intelligence are two second-order factors that are differentiated within the intelligence model by R.B.Cattell. Fluid intelligence is considered to be a biological capacity relatively independent of environmental influences. Crystallized intelligence, however, is connected to accultured skills and knowledge. The capacity of fluid intelligence decreases by non-optimal states of general activation, functional psychosis (physically founded reversible psychosis) or defect-syndromes (physically founded irreversible psychosis). Fluid intelligence can increase by drugs only, if the functional psychosis is diminished or if the state of activation is optimized. There is no drug-effect on crystallized intelligence but an indirect influence via fluid intelligence. The hypothesis of the drug-related increase of fluid intelligence as a correlate to the diminuition accompanying the functional psychosis should be confirmed by a clinical experiment. Therefore two samples of 20 patients each with a functional psychosis following cerebral blood-flow disturbances received flunarizine (Sibelium) and placebo respectively during a double-blind study lasting 12 weeks. Under the activ substance to be applied for amelioration of peripheral and central blood-flow the measured values of fluid intelligence increased six weeks after starting therapy, while there were no changes under placebo. In the end of the investigation the measured intellectual capacity had increased by 50 per cent under flunarizine.