A delusional disorder may develop from a preexisting paranoid personality disorder.
Beginning in early adulthood, individuals with a paranoid personality disorder have a pervasive distrust and suspiciousness of others and their motives.
Early symptoms of delusional disorder may include
- Feeling exploited;
- Being preoccupied with the loyalty or trustworthiness of friends;
- Reading threatening meanings into benign remarks or events;
- Bearing grudges for a long time; and
- Responding readily to perceived slights.
Behaviour is not obviously bizarre or odd.
Individuals with delusional disorder tend to function relatively well, except when their delusions cause problems.
For example, they may have marital problems if they are incorrectly convinced their spouse is being unfaithful.