Orexin receptor antagonists

1. A compound of formula

Wherein:

(i) Y 1 , Y 2 , Y 3 and Y 4 are independently a carbon or a nitrogen atom, wherein no more than one of Y 1 , Y 2 , Y 3 and Y 4 is a nitrogen atom;

(ii) W is selected from:

and

(iii) X is selected from:

2. The compound of claim 1 , wherein Y 1 is nitrogen.

3. The compound of claim 1 , wherein Y 4 is N.

4. The compound of claim 1 , wherein W is

5. The compound of claim 1 , wherein X is

6. The compound of claim 1 , wherein the compound is 2-(5,6-Dimethoxypyridin-3-yl)-4-(2,4,6-trifluorobenzyl)-2H-pyrido[2,3-e][1,2,4]thiadiazin-3(4H)-one 1,1-dioxide.

7. A pharmaceutical composition comprising the compound of claim 1 .

8. A method of treating, ameliorating, controlling or reducing the risk of a neurological or psychiatric disorder in a subject in need thereof, comprising administering to the subject an effective amount of the compound of claim 1 , wherein the neurological or psychiatric disorder is a movement disorder, an anxiety disorder, a panic disorder, a cognitive impairment or Alzheimer's disease.

9. A method of treating insomnia in a subject in need thereof, comprising administering to the subject an effective amount of the compound of claim 1 .

10. A method of treating migraine, cluster headache or other headache disorders in a subject in need thereof, comprising administering to the subject an effective amount of the compound of claim 1 .

11. A method of treating obesity in a subject in need thereof, comprising administering to the subject an effective amount of the compound of claim 1 .

12. A method of treating a binge eating disorder, a compulsive disorder or an impulse control disorder in a subject in need thereof, comprising administering to the subject an effective amount of the compound of claim 1 .