Study of ITI-1284 as Monotherapy Treatment in Patients With Generalized Anxiety Disorder

Inclusion Criteria:

* Provide written informed consent before the initiation of any study specific procedures;
* At Screening, meet Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR) diagnostic criteria for moderate or severe GAD (current GAD) as confirmed by the Investigator or Sponsor-approved rater using the Structured Clinical Interview for DSM-5 Clinical Trials Version (SCID-5-CT), and meets all of the following at Screening and Baseline:

  * HAM-A Total score of ≥ 22;
  * HAM-A Items 1 (anxious mood) and 2 (tension) scores ≥ 2;
  * CGI-S score of ≥ 4;
* History of inadequate response (\< 50% improvement in anxiety symptoms as measured by the modified Antidepressant Treatment Response Questionnaire \[ATRQ\] for GAD) to at least 2 of the following GAD-approved treatments: paroxetine, venlafaxine XR, duloxetine, escitalopram, or buspirone taken at an adequate dose (that is, at least a minimum total daily dose of paroxetine 20 milligram \[mg\], venlafaxine XR 75mg, duloxetine 60 mg, escitalopram 10mg, or buspirone 20 mg) and duration (ie, for at least 6 weeks prior to Screening) for the treatment of ongoing GAD symptoms.

Exclusion Criteria:

* Within the patient's lifetime, has one of the following confirmed DSM-5-TR psychiatric diagnoses:

  * Schizophrenia, Schizoaffective Disorder, Schizophreniform Disorder or other psychotic disorder;
  * Bipolar Disorder;
* MADRS total score \> 18 at Screening or Baseline;
* In the opinion of the Investigator, the patient has a significant risk for suicidal behavior during his/her participation in the study or

  * At Screening, the patient scores "yes" on Suicidal Ideation Items 4 or 5 of the C-SSRS within 6 months prior to Screening or, at Baseline, the patient scores "yes" on Suicidal Ideation Items 4 or 5 since the Screening Visit;
  * At Screening, the patient has had 1 or more suicidal attempts within the 2 years prior to Screening;
  * At Screening or Baseline MADRS Item 10 score ≥ 5; or
  * The patient is considered to be an imminent danger to him/herself or others based on the assessment of the Investigator;
* Lifetime history of failure to respond to \> 3 of the approved treatments for GAD (ie, paroxetine, venlafaxine XR, duloxetine, escitalopram, or buspirone) at an adequate dose (that is, at least a minimum total daily dose of paroxetine 20 mg, venlafaxine XR 75mg, duloxetine 60 mg, escitalopram 10mg, or buspirone 20 mg) and for an adequate duration (ie, at least 6 weeks)