Even when on medication, some people may still experience weaker episodes, or have a complete manic or depressive episode.
The following behaviors can lead to depressive or manic relapse:
Discontinuing or lowering one's dose of medication, without consulting one's physician.
Being under- or over-medicated. Generally, taking a lower dosage of a mood stabilizer can lead to relapse into mania. Taking a lower dosage of an antidepressant, may cause the patient to relapse into depression, while higher doses can cause destabilization into mixed-states or mania.
Taking hard drugs – recreationally or not – such as cocaine, alcohol, amphetamines, or opiates. These can cause the condition to worsen.
An inconsistent sleep schedule can destabilize the illness. Too much sleep (possibly caused by medication) can lead to depression, while too little sleep can lead to mixed states or mania.
Caffeine can cause destabilization of mood toward irritability, dysphoria, and mania. Anecdotal evidence seems to suggest that lower dosages of caffeine can have effects ranging from anti-depressant to mania-inducing.
Inadequate stress management and poor lifestyle choices. If un-medicated, excessive stress can cause the individual to relapse. Medication raises the stress threshold somewhat, but too much stress still causes relapse.
Relapse can be managed by the sufferer with the help of a close friend, based on the occurrence of idiosyncratic prodromal events. That is, by noticing which moods, activities / behaviors or thinking process / thought content typically occur at the outset of their episodes. They can then take pre-planned steps to slow or reverse the onset of illness, or take action to prevent the episode causing damage to important aspects of their life.