Treatment of schizophrenia and related disorders

1. A method for treating a psychotic disorder in a patient, in need thereof comprising:

(i) administering an amount of antipsychotic therapeutic agent to the patient; and

(ii) administering an amount of histamine H 3 antagonist; to said patient in need of treatment for a psychotic disorder;

wherein the histamine H 3 receptor antagonist is a compound of formula:

or a pharmaceutically acceptable salt thereof, wherein:

R 1 is alkyl, C 3 -C 5 cycloalkyl, or (C 3 -C 5 cycloalkyl)methyl;

R 2a , R 2b , R 2c , R 2d , R 2e , and R 2f each are independently hydrogen, methyl, or fluoromethyl;

R 3a , R 3b , R 3c , and R 3d are each independently hydrogen, alkyl, fluoroalkyl, fluoroalkoxy, alkoxy, thioalkoxy, halogen, or nitrile, with the proviso that when one or more of R 3a , R 3b , R 3c , and R 3d are alkyl, then at least one of R 3a , R 3b , R 3c , and R 3d is fluoroalkyl, fluoroalkoxy, alkoxy, thioalkoxy, halogen, or nitrile;

L, is a bond, oxygen, sulfur, carbonyl, alkylene, alkylcarbonyl, alkylamino, —C(═N-Oalkyl)-, NR 4 , —C(═O)NR 4 —, or —NR 4 C(═O)—;

L 2 is a bond, oxygen, sulfur, carbonyl, alkylene, alkylcarbonyl, alkylamino, —C(═N-Oalkyl)-, NR 5 , —C(═O)NR 5 —, or —NR 5 C(═O)—;

Cy 1 is aryl, cycloalkyl, cycloalkenyl, heteroaryl, or heterocycle;

Cy 2 is aryl, cycloalkyl, cycloalkenyl, heteroaryl or heterocycle, wherein the heteroaryl or heterocycle moiety has 1, 2, or 3 heteroatoms selected from nitrogen, oxygen, and sulfur, provided that at least one heteroatom is nitrogen; and

R 4 and R 5 at each occurrence is hydrogen or alkyl;

provided that Cy 2 is not

2. The method of claim 1 , wherein the amounts of (i) and (ii) together are effective in treating a psychotic disorder.

3. The method of claim 1 , wherein L 1 is a bond; L 2 is a bond; R 3a , R 3b , R 3c , and R 3d are all hydrogen; Cy 1 is phenyl, and Cy 2 is aryl, cycloalkyl, cycloalkenyl, heteroaryl or heterocycle, wherein the heteroaryl or heterocycle moiety has 1, 2, or 3 heteroatoms selected from nitrogen, oxygen, and sulfur, provided that at least one heteroatom is nitrogen.

4. The method of claim 3 , wherein Cy 2 is pyridazinone.

5. The method of claim 1 , wherein the histamine H 3 receptor antagonist is 2-{4′-[(3aR,6aR)-5-methylhexahydropyrrolo[3,4-b]pyrrol-1(2H)-yl]-1,1′-biphenyl-4-yl}pyridazin-3(2H)-one.

6. The method of claim 1 , wherein the histamine H 3 receptor antagonist is 2-{5-[4-((3aR,6aR)-5-methyl-hexahydro-pyrrolo[3,4-b]pyrrol-1-yl)-phenyl]-pyridin-2-yl}-2H-pyridazin-3-one.

7. The method of claim 2 , wherein the amount of (ii) is a sub efficacious amount.