Indications for Chronotherapy.
Chronotherapy has been found to benefit most forms of depression including:

Unipolar Depression
Depression with melancholic features
Bipolar Depression
Fall/Winter Depression (Seasonal Affective Disorder)

In addition to these diagnostic indications, chronotherapy is also useful in the following circumstances:

When there is a need for a rapid antidepressant response; in other words, when someone needs to get better quickly

Inability to tolerate, or preference to avoid medication.
Most often, chronotherapy is used along with antidepressant or mood-stabilizing medication. It can, however, be used on it's own, especially when several different forms of chronotherapy are used in combination.

This option allows for a fully non-pharmacologic treatment for those who are sensitive to, or need to minimize medication side-effects; for example, those with other medical illnesses, the elderly, and for antepartum and post-partum depressions.

Contraindications to the use of Chronotherapy

Psychotic Depression.
People who are experiencing hallucinations or delusions while depressed (or when manic) should not receive chronotherapy.

Mixed States (the simultaneous co-occurance of both manic and depressive states) or depressive states with significant anxiety or other manic symptoms (relative contraindication).
Chronotherapy, like all other biological forms of antidepressant treatment, can cause emotional side effects. About 7% of patients treated with wake therapy will develop hypomanic symptoms. Patients experiencing manic or significant anxiety symptoms as part of their depression are at a higher risk of having this reaction. It is therefore contraindicated in this group.

Certain eye conditions may limit the use of bright light treatment.
Retinal problems, macular degeneration and the use of photosensitizing medications may complicate or prevent the use of light treatment.

The presence of epilepsy or a seizure disorder is a relative contraindication for wake therapy.
The use of antipsychotic drugs, sleep medications (sedatives), or certain anti-anxiety agents can interfere with the action of wake therapy and may need to be discontinued or temporarily suspended.