Methods

1. A method for the treatment of acute depression or acute anxiety comprising administering to a patient in need thereof, a therapeutically effective amount of a Compound of Formula I:

wherein:

X is —N(H)—, —N(CH 3 )— or −O—;

L is O;

Z is —O—;

in free, or pharmaceutically acceptable salt form;

wherein the patient shows an acute response to treatment within less than 3 weeks.

2. The method according to claim 1 , wherein X in the compound of Formula I is —N(H)—, or —N(CH 3 )—.

3. The method according to claim 2 , wherein X in the compound of Formula I is —N(H)—.

4. The method according to claim 1 , wherein the Compound of Formula I is:

5. The method according to claim 4 , wherein the Compound of Formula I is in the form of the tosylate salt.

6. The method according to claim 1 , wherein the method comprises once daily administration of a unit dosage comprising the compound of Formula I in tosylate salt form in an amount equivalent to 1 to 100 mg of free base, and a pharmaceutically acceptable diluent or carrier.

7. The method according to claim 1 , wherein the condition to be treated is acute anxiety.

8. The method according to claim 1 , wherein the condition to be treated is acute depression.

9. The method according to claim 1 , wherein the condition to be treated is treatment resistant depression.

10. The method according to claim 1 , wherein the Compound of Formula I is in combination with an effective amount of an additional anxiolytic or antidepressant agent.

11. The method according to claim 10 , wherein the anxiolytic or antidepressant agent is selected from one or more compounds in free or pharmaceutically acceptable salt form, selected from selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), and atypical antipsychotics.

12. The method according to claim 1 , wherein the method enhances mTOR signaling.

13. The method according to claim 1 , wherein the method reduces neuroinflammation.

14. The method according to claim 1 , wherein the compound of Formula I is administered intra-nasally, subcutaneously, intravenously, orally, sub-lingually, intra-peritoneally, or buccally.

15. The method according to claim 1 , wherein the method further comprises the concurrent administration of an NMDA receptor antagonist.

16. The method according to claim 1 , wherein the method further comprises the concurrent administration of a NMDA receptor allosteric modulator.

17. The method according to claim 1 , wherein the patient has not responded to, or has not responded adequately to, or who suffers undesirable side effects from, treatment with another antidepressant agent.

18. The method according to claim 1 , wherein the Compound of Formula I is administered as monotherapy.

19. The method according to claim 1 , wherein the method does not put the patient at risk for sedation, dissociation, abuse, misuse, or suicidal ideation, or does not result in hypertension within four hours after administration of a dose of the Compound of Formula I.

20. The method according to claim 7 , wherein the acute anxiety is selected from-short-duration anxious episode associated with generalized anxiety disorder, panic disorder, specific phobias, or social anxiety disorder, and social avoidance.

21. The method according to claim 8 , wherein the acute depression is selected from acute major depressive episode, acute short-duration depressive episode, and acute recurrent brief depressive episode.

22. The method according to claim 9 , wherein the treatment resistant depression is depression which has not responded to treatment with an antidepressant agent selected from a selective serotonin reuptake inhibitor (SSRI), a serotonin reuptake inhibitor (SRI), a tricyclic antidepressant, a monoamine oxidase inhibitor, a norepinephrine reuptake inhibitor (NRI), a dopamine reuptake inhibitor (DRI), an SRI/NRI, an SRI/DRI, an NRI/DRI, an SRI/NRI/DRI (triple reuptake inhibitor), a serotonin receptor antagonist, or any combination thereof.

23. The method according to claim 17 , wherein the patient has not responded to, or has not responded adequately to, or who suffers undesirable side effects from, treatment with another antidepressant agent selected from a selective serotonin reuptake inhibitor (SSRI), a serotonin reuptake inhibitor (SRI), a tricyclic antidepressant, a monoamine oxidase inhibitor, a norepinephrine reuptake inhibitor (NRI), a dopamine reuptake inhibitor (DRI), an SRI/NRI, an SRI/DRI, an NRI/DRI, an SRI/NRI/DRI (triple reuptake inhibitor), and a serotonin receptor antagonist.

24. The method according to claim 1 , wherein the patient shows an acute response to treatment within 1 to 7 days.

25. The method according to claim 1 , wherein the patient shows an acute response to treatment within less than 1 week.

26. The method according to claim 1 , wherein the patient shows an acute response to treatment within less than 2 days.