Light and Ion Maintenance In Treatment for Depression (LIMIT-D): Feasibility Study

Prior treatment

• History of alcohol or substance use disorder, with a severity of at least moderate or severe, within 6 months before screening.
• Use of photosensitizing medication (thioridazine, chloroquine, 8-methoxypsoralen) within 1 week of baseline visit.
• Initiated formal psychotherapy (e.g., cognitive-behavioural therapy) within 3 months of Visit 1, or who plan to initiate psychotherapy during the study.

Other illness

• Any psychiatric diagnosis other than MDD that is considered the primary diagnosis, including Bipolar I or Bipolar-II (lifetime). Note that comorbid anxiety disorders (e.g., generalized anxiety disorder, social anxiety disorder) will not be excluded if the anxiety disorder is not the primary diagnosis.
• Diagnosis of MDD with seasonal pattern (i.e., seasonal affective disorder, SAD) or with psychotic features (lifetime).
• Significant personality disorder diagnosis \[e.g., antisocial\] by MINI and clinical assessment.
• Significant neurological disorders, head trauma, or other unstable medical conditions.
• Regular use of psychotropic medication other than an antidepressant or benzodiazepines (e.g., antipsychotics, mood stabilizers); Note - Stimulant medications for Attention-Deficit Hyperactivity Disorder are allowed if dose is stable in past month.
• History of severe antidepressant discontinuation effects.
• Retinal disease or other eye condition (e.g., macular degeneration) precluding the use of bright light treatment.

Other

• High suicidal risk, defined by clinician judgment.
• Continued use of any other evidence-based treatment for depression.

• Diagnostic and Statistical Manual (DSM-5) criteria for MDD, as determined by the Structured Clinical Interview for DSM-5 (SCID).
• Taking a first-line antidepressant at approved doses (Table 1), with dose unchanged in the past month.
• Participant desire to discontinue antidepressant treatment because of adverse effects or other reasons;
• In remission as defined by score ≤10 on the clinician-rated Montgomery-Asberg Depression Rating Scale (MADRS) at both the screening visit and baseline visit, at least 2 weeks apart.
• Willing and able to complete self-report and online assessments including sufficient fluency in English or French.